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Zhang, Chenhao, Xin Nie, Weilong Kong, Xiaoxiao Deng, Tong Sun, Xuhui Liu, and Yangsheng Li. "Genome-Wide Identification and Evolution Analysis of the Gibberellin Oxidase Gene Family in Six Gramineae Crops." Genes 13, no. 5 (May 12, 2022): 863. http://dx.doi.org/10.3390/genes13050863.
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The plant hormones gibberellins (GAs) regulate plant growth and development and are closely related to the yield of cash crops. The GA oxidases (GAoxs), including the GA2ox, GA3ox, and GA20ox subfamilies, play pivotal roles in GAs’ biosynthesis and metabolism, but their classification and evolutionary pattern in Gramineae crops remain unclear. We thus conducted a comparative genomic study of GAox genes in six Gramineae representative crops, namely, Setaria italica (Si), Zea mays (Zm), Sorghum bicolor (Sb), Hordeum vulgare (Hv), Brachypodium distachyon (Bd), and Oryza sativa (Os). A total of 105 GAox genes were identified in these six crop genomes, belonging to the C19-GA2ox, C20-GA2ox, GA3ox, and GA20ox subfamilies. Based on orthogroup (OG) analysis, GAox genes were divided into nine OGs and the number of GAox genes in each of the OGs was similar among all tested crops, which indicated that GAox genes may have completed their family differentiations before the species differentiations of the tested species. The motif composition of GAox proteins showed that motifs 1, 2, 4, and 5, forming the 2OG-FeII_Oxy domain, were conserved in all identified GAox protein sequences, while motifs 11, 14, and 15 existed specifically in the GA20ox, C19-GA2ox, and C20-GA2ox protein sequences. Subsequently, the results of gene duplication events suggested that GAox genes mainly expanded in the form of WGD/SD and underwent purification selection and that maize had more GAox genes than other species due to its recent duplication events. The cis-acting elements analysis indicated that GAox genes may respond to growth and development, stress, hormones, and light signals. Moreover, the expression profiles of rice and maize showed that GAox genes were predominantly expressed in the panicles of the above two plants and the expression of several GAox genes was significantly induced by salt or cold stresses. In conclusion, our results provided further insight into GAox genes’ evolutionary differences among six representative Gramineae and highlighted GAox genes that may play a role in abiotic stress.
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He, Liang, Lu, Wang, Liu, Ma, Zuo, Sun, Chen, and Mao. "Genome-Wide Identification and Expression Analysis of GA2ox, GA3ox, and GA20ox Are Related to Gibberellin Oxidase Genes in Grape (Vitis Vinifera L.)." Genes 10, no. 9 (September 5, 2019): 680. http://dx.doi.org/10.3390/genes10090680.
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Gibberellin (GAs) plays the important role in the regulation of grape developmental and growth processes. The bioinformatics analysis confirmed the differential expression of GA2, GA3, and GA20 gibberellin oxidase genes (VvGA2oxs, VvGA3oxs, and VvGA20oxs) in the grape genome, and laid a theoretical basis for exploring its role in grape. Based on the Arabidopsis GA2oxs, GA3oxs, and GA20oxs genes already reported, the VvGA2oxs, VvGA3oxs, and VvGA20oxs genes in the grape genome were identified using the BLAST software in the grape genome database. Bioinformatics analysis was performed using software such as DNAMAN v.5.0, Clustalx, MapGene2Chrom, MEME, GSDS v.2.0, ExPASy, DNAsp v.5.0, and MEGA v.7.0. Chip expression profiles were generated using grape Affymetrix GeneChip 16K and Grape eFP Browser gene chip data in PLEXdb. The expression of VvGA2oxs, VvGA3oxs, and VvGA20oxs gene families in stress was examined by qRT-PCR (Quantitative real-time-PCR). There are 24 GAoxs genes identified with the grape genome that can be classified into seven subgroups based on a phylogenetic tree, gene structures, and conserved Motifs in our research. The gene family has higher codon preference, while selectivity is negative selection of codon bias and selective stress was analyzed. The expression profiles indicated that the most of VvGAox genes were highly expressed under different time lengths of ABA (Abscisic Acid) treatment, NaCl, PEG and 5 °C. Tissue expression analysis showed that the expression levels of VvGA2oxs and VvGA20oxs in different tissues at different developmental stages of grapes were relatively higher than that of VvGA3oxs. Last but not least, qRT-PCR (Real-time fluorescent quantitative PCR) was used to determine the relative expression of the GAoxs gene family under the treatment of GA3 (gibberellin 3) and uniconazole, which can find that some VvGA2oxs was upregulated under GA3 treatment. Simultaneously, some VvGA3oxs and VvGA20oxs were upregulated under uniconazole treatment. In a nutshell, the GA2ox gene mainly functions to inactivate biologically active GAs, while GA20ox mainly degrades C20 gibberellins, and GA3ox is mainly composed of biologically active GAs. The comprehensive analysis of the three classes of VvGAoxs would provide a basis for understanding the evolution and function of the VvGAox gene family in a grape plant.
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Phong, Ong Xuân, Lý Khánh Linh, La Việt Hồng, Đỗ Tiến Phát, and Phạm Bích Ngọc. "BIẾN NẠP VÀ ĐÁNH GIÁ CÁC DÒNG XOAN TA (Melia azedarach L.) MANG GEN GA20-OXIDASE ĐƯỢC ĐIỀU KHIỂN BỞI PROMOTER GmPrP2." TNU Journal of Science and Technology 227, no. 14 (September 15, 2022): 113–20. http://dx.doi.org/10.34238/tnu-jst.6356.
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Cây xoan ta là một cây lâm nghiệp có nhiều công dụng, ở Việt Nam cây xoan được trồng khá phổ biến. Trong nghiên cứu này cấu trúc mang gen GA20ox mã hoá cho enzyme GA20-oxidase đóng vai trò quan trọng trong quá trình sinh tổng hợp GA ở tế bào thực vật đã được chuyển vào cây xoan ta bằng vector GmPrP2:GA20ox. Kết quả kiểm tra sự có mặt của gen GA20ox bằng kỹ thuật PCR có 15 dòng mang gen. Các dòng xoan mang gen chuyển được đánh giá mức độ biểu hiện ở cấp độ phân tử bằng kỹ thuật RT-PCR cho kết quả gen GA20ox đã hoạt động. Đánh giá sinh trưởng các dòng mang gen chuyển sau 8 tuần tuổi thì dòng T16, T20 và T22 có chiều cao và số đốt tăng 150 - 200% so với đối chứng. Giải phẫu đốt thân thứ 8 cho thấy mật độ sợi xylem và số tế bào trên sợi xylem của các dòng mang gen chuyển đều cao hơn dòng đối chứng, còn độ dày thành tế bào các dòng tương tự nhau. Những kết quả này bước đầu chứng minh vai trò của promoter GmPrP2 với gen GA20ox đối với quá trình tăng trưởng và cải thiện sinh khối ở cây thân gỗ.
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Ma, Jikai, and Huogen Li. "The Formation of Shapes: Interplay of Genes during Leaf Development Processes." Forests 13, no. 10 (October 20, 2022): 1726. http://dx.doi.org/10.3390/f13101726.
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Leaf shape, as one of the clearest manifestations of plant morphology, shows considerable variation owing to genetics and the environment. Leaf initiation occurs in the peripheral zone of the SAM and goes through the three overlapping phases of leaf primordium initiation, leaf dorsiventral development, and leaf marginal meristem establishment. Transcription factors, such as KNOX, WOX, and CUC; hormone-regulating genes, such as GA2ox, GA20ox, and PIN1; and miRNAs such as miR164/165 are tightly involved in leaf shaping through the generation of intricate cooperative networks in different temporal phases and specific tissue zones. Here, we briefly discuss the critical interplay occurring between certain genes and the pivotal role these play in the leaf developmental network and phytohormone regulation, including AS1/AS2–KNOX–GA20ox–GA, miR164–NAM/CUC–PIN1–auxin, and CUC–BAS1/CYP734A–BR, and we attempt to summarize several basic insights into the mechanisms of leaf shape regulation.
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Sun, Xiaorong, Jinshuai Shu, Ali Mohamed Ali Mohamed, Xuebin Deng, Xiaona Zhi, Jinrui Bai, Yanan Cui, et al. "Identification and Characterization of EI (Elongated Internode) Gene in Tomato (Solanum lycopersicum)." International Journal of Molecular Sciences 20, no. 9 (May 5, 2019): 2204. http://dx.doi.org/10.3390/ijms20092204.
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Internode length is an important agronomic trait affecting plant architecture and crop yield. However, few genes for internode elongation have been identified in tomato. In this study, we characterized an elongated internode inbred line P502, which is a natural mutant of the tomato cultivar 05T606. The mutant P502 exhibits longer internode and higher bioactive GA concentration compared with wild-type 05T606. Genetic analysis suggested that the elongated internode trait is controlled by quantitative trait loci (QTL). Then, we identified a major QTL on chromosome 2 based on molecular markers and bulked segregant analysis (BSA). The locus was designated as EI (Elongated Internode), which explained 73.6% genetic variance. The EI was further mapped to a 75.8-kb region containing 10 genes in the reference Heinz 1706 genome. One single nucleotide polymorphism (SNP) in the coding region of solyc02g080120.1 was identified, which encodes gibberellin 2-beta-dioxygenase 7 (SlGA2ox7). SlGA2ox7, orthologous to AtGA2ox7 and AtGA2ox8, is involved in the regulation of GA degradation. Overexpression of the wild EI gene in mutant P502 caused a dwarf phenotype with a shortened internode. The difference of EI expression levels was not significant in the P502 and wild-type, but the expression levels of GA biosynthetic genes including CPS, KO, KAO, GA20ox1, GA20ox2, GA20ox4, GA3ox1, GA2ox1, GA2ox2, GA2ox4, and GA2ox5, were upregulated in mutant P502. Our results may provide a better understanding of the genetics underlying the internode elongation and valuable information to improve plant architecture of the tomato.
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Zheng, Feng, Yahan Wang, Dachuan Gu, and Xuncheng Liu. "Histone Deacetylase HDA15 Restrains PHYB-Dependent Seed Germination via Directly Repressing GA20ox1/2 Gene Expression." Cells 11, no. 23 (November 26, 2022): 3788. http://dx.doi.org/10.3390/cells11233788.
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Seed germination is essential for the colonization of the land plants. Light is a major environmental factor affecting seed germination, which is predominantly regulated by photoreceptor phytochrome B (PHYB). PHYB is activated by red light (designated as PHYB-on) whereas it is inactivated by far-red light (referred as PHYB-off). We previously reported that Arabidopsis histone deacetylase HDA15 interacts with phytochrome-interacting factor1 (PIF1) to repress seed germination under PHYB-off conditions. Here, we show that HDA15 plays a negative role in regulating seed germination under PHYB-on conditions. Overexpression of HDA15 in Arabidopsis restrains PHYB-dependent seed germination, while gibberellin (GA) relieves the repressive role of HDA15 under PHYB-off conditions. We further show that HDA15 directly binds to GA20ox1 and GA20ox2, two key GA biosynthesis genes and represses their expression by removal of histone H3 and H4 acetylation. Moreover, the levels of HDA15 transcript and HDA15 protein are up-regulated in the phyB mutant. Collectively, our work proposes that HDA15 acts as a negative regulator of PHYB-dependent seed germination by directly repressing GA20ox1/2 gene expression.
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Ding, Qiangqiang, Feng Wang, Juan Xue, Xinxin Yang, Junmiao Fan, Hong Chen, Yi Li, and Han Wu. "Identification and Expression Analysis of Hormone Biosynthetic and Metabolism Genes in the 2OGD Family for Identifying Genes That May Be Involved in Tomato Fruit Ripening." International Journal of Molecular Sciences 21, no. 15 (July 28, 2020): 5344. http://dx.doi.org/10.3390/ijms21155344.
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Phytohormones play important roles in modulating tomato fruit development and ripening. The 2-oxoglutarate-dependent dioxygenase (2OGD) superfamily containing several subfamilies involved in hormone biosynthesis and metabolism. In this study, we aimed to identify hormone biosynthesis and metabolism-related to 2OGD proteins in tomato and explored their roles in fruit development and ripening. We identified nine 2OGD protein subfamilies involved in hormone biosynthesis and metabolism, including the gibberellin (GA) biosynthetic protein families GA20ox and GA3ox, GA degradation protein families C19-GA2ox and C20-GA2ox, ethylene biosynthetic protein family ACO, auxin degradation protein family DAO, jasmonate hydroxylation protein family JOX, salicylic acid degradation protein family DMR6, and strigolactone biosynthetic protein family LBO. These genes were differentially expressed in different tomato organs. The GA degradation gene SlGA2ox2, and the auxin degradation gene SlDAO1, showed significantly increased expression from the mature-green to the breaker stage during tomato fruit ripening, accompanied by decreased endogenous GA and auxin, indicating that SlGA2ox2 and SlDAO1 were responsible for the reduced GA and auxin concentrations. Additionally, exogenous gibberellin 3 (GA3) and indole-3-acetic acid (IAA) treatment of mature-green fruits delayed fruit ripening and increased the expression of SlGA2ox2 and SlDAO1, respectively. Therefore, SlGA2ox2 and SlDAO1 are implicated in the degradation of GAs and auxin during tomato fruit ripening.
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Teshome, Shiferaw, and Mulugeta Kebede. "Analysis of regulatory elements in GA2ox, GA3ox and GA20ox gene families in Arabidopsis thaliana: an important trait." Biotechnology & Biotechnological Equipment 35, no. 1 (January 1, 2021): 1603–12. http://dx.doi.org/10.1080/13102818.2021.1995494.
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Ashikari, Motoyuki, Akie Sasaki, Miyako Ueguchi-Tanaka, Hironori Itoh, Asuka Nishimura, Swapan Datta, Kanako Ishiyama, et al. "Loss-of-function of a Rice Gibberellin Biosynthetic Gene, GA20 oxidase (GA20ox-2), Led to the Rice ‘Green Revolution’." Breeding Science 52, no. 2 (2002): 143–50. http://dx.doi.org/10.1270/jsbbs.52.143.
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Yue, Jing, Heyu Yang, Shaohui Yang, and Jiehua Wang. "TDIF overexpression in poplars retards internodal elongation and enhances leaf venation through interaction with other phytohormones." Tree Physiology 40, no. 1 (December 19, 2019): 60–72. http://dx.doi.org/10.1093/treephys/tpz126.
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Abstract As a member of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION-related (CLE) peptide family, tracheary element differentiation inhibitory factor (TDIF) plays crucial roles in vascular meristem maintenance by promoting cell proliferation and inhibiting xylem cell differentiation. In Populus trichocarpa, six TDIF-encoding genes are all expressed in vascular tissues, and in Arabidopsis PtTDIFpro:GUS lines, the expression driven by PtTDIF promoters were predominantly detected in stem vascular bundles, initiating leaves and leaf veins. Although exogenous application of two poplar TDIF peptides did not evidently affect the shoot growth in vitro, overexpression of PtTDIF genes in hybrid poplar severely retarded the internodal elongation by upregulating the expression of GA2ox and GA20ox genes and thus decreasing the level of endogenous gibberellins (GAs), which phenotypic defect could be rescued by exogenously applied GA3. In addition, TDIF overexpression unexpectedly induced a more complex venation pattern in poplar leaves, which was underpinned by the elevated expression of WOX4 and WOX13 genes. Upon TDIF treatment, the DR5:GUS poplar leaves revealed a higher GUS activity and in TDIF-overexpressing leaves, the transcript abundances of several PIN-FORMED (PIN) genes, especially that of PIN1, were increased, which implied an integration of TDIF and auxin in mediating this process. Collectively, data of this work presented novel activities of TDIF involved in internode elongation and leaf vein formation, thus revealing the divergent functions of TDIF in perennial tree species from those in annual herbaceous Arabidopsis.
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Li, Lu, Jiaqi Wang, Jiajun Chen, Zhihua Wang, Mirza Faisal Qaseem, Huiling Li, and Aimin Wu. "Physiological and Transcriptomic Responses of Growth in Neolamarckia cadamba Stimulated by Exogenous Gibberellins." International Journal of Molecular Sciences 23, no. 19 (October 6, 2022): 11842. http://dx.doi.org/10.3390/ijms231911842.
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(1) The phytohormones gibberellins (GAs) play a crucial role in plant growth and development, such as seed germination, flowering, fruiting, and stem elongation. Although many biological roles of GAs have been studied intensively, the molecular mechanisms of GAs in woody plants are still unclear. (2) In this study, we investigated the effects of exogenous application of GAs on Neolamarckia cadamba. (3) The height and biomass of N. cadamba increased after 7 days of GA treatment, especially on the second internode. Transcriptome analysis showed that although the majority of genes involved in the GA signaling pathway were up-regulated, the expression of GA20 oxidase (GA20ox) and GA3 oxidase (GA3ox) was down-regulated in the 3 days GA-treated group compared to the CK group. The expression of the cell elongation-related basic helix-loop-helix genes bHLH74 and bHLH49 was up-regulated in the GA-treated group compared with the CK group. Transcriptional expression levels of transcription factors involved in hormone signaling were changed, mainly including bHLH, ethylene response factor (ERF), and WRKY families. In addition, the transcriptional expression level of the key enzymes engaged in the phenylalanine pathway was downregulated after GA treatment. (4) In brief, our findings reveal the physiological and molecular mechanisms of exogenous GA treatment stimulation in N. cadamba.
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Gombé-Apondza, Guy-Roger Cyriac. "Syntagme qualificatif en akwá, langue bantu (C22) parlée en République du Congo." Cahiers Africains de rhétorique 1, no. 2 (December 30, 2022): 24–36. http://dx.doi.org/10.55595/ga2022.
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The present work describes, based on European structuralism, the qualifying phrase in Akwá, a language classified by the linguistic literature in zone C and group C20. The qualifying phrase is obviously a phrase with qualifying determination, fundamentally constituted around two elements, which are the qualified, and the qualifying. Depending on whether it is unmarked or marked, this syntagm can be made up of elements, which follow one another without a relator or can belinked to one another by means of a copula verb or a functional of the prepositive type. Keywords: phrase, qualifying phrase, qualified, qualifying, akwá.
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Qu, Yinquan, Xiaolin Chen, Xia Mao, Peng Huang, and Xiangxiang Fu. "Transcriptome Analysis Reveals the Role of GA3 in Regulating the Asynchronism of Floral Bud Differentiation and Development in Heterodichogamous Cyclocarya paliurus (Batal.) Iljinskaja." International Journal of Molecular Sciences 23, no. 12 (June 17, 2022): 6763. http://dx.doi.org/10.3390/ijms23126763.
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Cyclocarya paliurus is an important medical plant owing to the diverse bioactive compounds in its leaves. However, the heterodichogamy with female and male functions segregation within protandry (PA) or protogyny (PG) may greatly affect seed quality and its plantations for medicinal use. To speculate on the factor playing the dominant role in regulating heterodichogamy in C. paliurus, based on phenotypic observations, our study performed a multi comparison transcriptome analysis on female and male buds (PG and PA types) using RNA-seq. For the female and male bud comparisons, a total of 6753 differentially expressed genes (DEGs) were detected. In addition, functional analysis revealed that these DEGs were significantly enriched in floral development, hormone, and GA-related pathways. As the dominant hormones responsible for floral differentiation and development, gibberellins (GAs) in floral buds from PG and PA types were quantified using HPLC-MS. Among the tested GAs, GA3 positively regulated the physiological differentiation (S0) and germination (S2) of floral buds. The dynamic changes of GA3 content and floral morphological features were consistent with the expression levels of GA-related genes. Divergences of GA3 contents at S0 triggered the asynchronism of physiological differentiation between male and female buds of intramorphs (PA-M vs. PA-F and PG-F vs. PG-M). A significant difference in GA3 content enlarged this asynchronism at S2. Thus, we speculate that GA3 plays the dominant role in the formation of heterodichogamy in C. paliurus. Meanwhile, the expression patterns of GA-related DEGs, including CPS, KO, GA20ox, GA2OX, GID1, and DELLA genes, which play central roles in regulating flower development, coincided with heterodichogamous characteristics. These results support our speculations well, which should be further confirmed.
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Mubarok, Husni, Panjisakti Basunanda, and Tri Joko Santoso. "Tolerance of T2 Generation ‘Kitaake’ Rice (Oryza sativa L.) CRISPR/Cas9-OsGA20ox-2 Mutant Strains to Drought Condition." Ilmu Pertanian (Agricultural Science) 4, no. 3 (November 29, 2019): 123. http://dx.doi.org/10.22146/ipas.37032.
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Rice (Oryza sativa L.) is important staple crop in Indonesia. Food demand that continues to rise while inadequate land could be managed by assembling superior cultivar using CRISPR-Cas9 system method. Editing the genome by mutating the GA20ox-2 gene could improve both crop yield and ability to thrive in marginal land (drought). This experiment aims to obtain non-transgenic mutant plants (non Cas9 and hpt genes), gain information on GA20ox-2 gene expression levels, and study the tolerance levels of the CRISPR /Cas9-OsGA20ox-2 mutant lines 'Kitaake' T2 generation against drought conditions. Planting material using a mutant gene GA20ox 2 ‘Kitaake’ (K23.1, K15, K29.1, K19.1) and wild-type comparison. From 20 plants, respectively the K23.1, K15, K29.1, and K19.1 lines have 50%, 50%, 0%, and 45% of non-transgenic plants. DNA mutations in the form of deletion 44 bases (K23.1, K29.1, K19.1) and insertion of two bases (K15) are transcribed into RNA. The transcription results in a number of lower amino acids compare to its wild type (389 amino acids). The lines K23.1, K29.1, K19.1 have 373 amino acids and the K15 line has 300 amino acids (frameshift). Differences in the number of amino acids result in different phenotypic expressions. K15 mutant line has lower plant height and leaf length than the other mutant lines and wild type. The decrease does not decrease the potential of the crop. Mutations in the K15 line did not indicate better tolerant response to drought stress than other mutant lines and wild type in both vegetative and generative phase.
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Pang, Yongqi, Jintong Li, Bishu Qi, Mi Tian, Lirong Sun, Xuechen Wang, and Fushun Hao. "Aquaporin AtTIP5;1 as an essential target of gibberellins promotes hypocotyl cell elongation in Arabidopsis thaliana under excess boron stress." Functional Plant Biology 45, no. 3 (2018): 305. http://dx.doi.org/10.1071/fp16444.
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Aquaporins play essential roles in growth and development including stem elongation in plants. Tonoplast aquaporin AtTIP5;1 has been proposed to positively regulate hypocotyl elongation under high concentrations of boron (high-B) in Arabidopsis thaliana (L.) Heynh. However, the mechanism underlying this process remains unanswered. Here, we show that paclobatrazol, an inhibitor of GA biosynthesis, significantly suppressed the hypocotyl cell elongation of wild-type (WT) seedlings, and more strongly suppressed that of AtTIP5;1 overexpressors under high-B stress. Two AtTIP5;1 null mutants displayed arrested elongation of cells in the upper part of hypocotyls compared with the WT in the presence of high-B or GA3. Moreover, paclobatrazol treatment completely inhibited the increases in AtTIP5;1 transcripts induced by high-B, whereas GA3 application upregulated AtTIP5;1 expression in the WT. In addition, treatment with high-B remarkably elevated the expression levels of GA3ox1, GA20ox1 and GA20ox2 – key biosynthesis genes of GAs – in WT seedlings. The GA3 and GA4 content also increased in WT seedlings grown in MS medium containing high-B. Additionally, application of high-B failed to enhance AtTIP5;1 expression in the double mutant rga-24–gai-t6 of DELLA genes. Together, these results suggest that AtTIP5;1 is an essential downstream target of GAs. High-B induces the accumulation of GAs, which activates AtTIP5;1 through modulation of the DELLA proteins Repressor of ga1–3 and GA-insensitive, further promoting hypocotyl elongation in A. thaliana.
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Ling, Li-Zhen, and Shu-Dong Zhang. "Comparative proteomic analysis between mature and germinating seeds in Paris polyphylla var. yunnanensis." PeerJ 10 (May 11, 2022): e13304. http://dx.doi.org/10.7717/peerj.13304.
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The long dormancy period of Paris polyphylla var. yunnanensis seeds affects the supply of this scarce plant, which is used as an important traditional Chinese medicine. Mature seeds with a globular embryo and germinating seeds with developed embryo were used to explore the mechanisms of seed germination in this species. The protein profiles between the mature and germinating seeds were compared using the isobaric tags for relative and absolute quantification (iTRAQ) approach. Of the 4,488 proteins identified, a total of 1,305 differentially expressed proteins (DEPs) were detected. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of these DEPs indicated that metabolic pathways and the biosynthesis of secondary metabolites were the two top pathways. Additionally, phytohormone quantification shows that the abscisic acid (ABA) level significantly decreased, whereas the GA3 level dramatically increased among nine endogenous gibberellins (GAs), resulting in a significant increase of the GA3/ABA ratio in germinating seeds. The biosynthesis pathways of carotenoid as a precursor for ABA production and GA were further analyzed, and showed that proteinic expressions of the candidate genes in the two pathways did not correlate with the transcriptional abundances. However, 9-cis-epoxycarotenoid dioxygenase (NCED), a rate limited enzyme for ABA biosynthesis, was significantly decreased in mRNA levels in germinating seeds. By contrast, gibberellin 20-oxidase (GA20ox), a key enzyme GA biosynthesis, exhibited the major increase in one copy and a slight decrease in three others at the protentional level in germinating seeds. Gibberellin 2-oxidase (GA2ox), an inactivate enzyme in bioactive GAs, has the tendency to down-regulate in mRNA or at the proteinic level in germinating seeds. Altogether, these results suggested that the analyses of ABA and GA levels, the GA3/ABA ratio, and the expressional patterns of their regulatory genes may provide a novel mechanistic understanding of how phytohormones regulate seed germination in P. polyphylla var. yunnanensis.
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Dong, Yuhui, Mengjiao Guan, Lixia Wang, Lei Yuan, Xiudong Sun, and Shiqi Liu. "Transcriptome Analysis of Low-Temperature-Induced Breaking of Garlic Aerial Bulb Dormancy." International Journal of Genomics 2019 (August 7, 2019): 1–16. http://dx.doi.org/10.1155/2019/9140572.
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The long history of asexual reproduction of garlic using garlic cloves has resulted in virus accumulation and genetic depression. Propagation of garlic seedlings by tissue culture can both eliminate viruses and improve breeding efficiency. Aerial bulbs are the first-choice materials for breeding virus-free garlic seedlings under external conditions, but they show dormancy just like garlic bulbs. However, low temperatures can quickly break dormancy. In this research, we used a high-throughput sequencing method to sequence aerial bulbs during dormancy and after low-temperature-induced breaking of dormancy to screen out the key differentially expressed genes (DEGs) associated with low temperature and to provide a theoretical basis for exploring the molecular mechanism of low-temperature-induced breaking of aerial bulb dormancy. The high-throughput transcriptome sequencing results showed that 6,675 DEGs were upregulated and 36,596 DEGs were downregulated in the aerial bulbs given low-temperature treatment. Then, 19,507 DEGs were assigned KEGG annotations, among which most DEGs were annotated to the metabolism pathway (11,817 genes, accounting for 60.58%), followed by the genetic information processing pathway (4,521 genes, accounting for 23.18%). The DEGs were mostly concentrated in pathways such as protein processing in the endoplasmic reticulum, plant-pathogen interaction, plant hormone signal transduction, and ribosome biogenesis in eukaryotes, with significant enrichment. The key DEGs related to calcium signaling, hormonal signaling, and transcription factors were screened out, including CaM, CDPK, and CML in accessory pathways of calcium signaling; GA20ox, GAI1, and GA2ox in accessory pathways of hormonal signaling; and transcription factor genes such as MYB, AP2/ERF, bHLH, MADS, and bZIP. qRT-PCR verification results were consistent with the sequencing results, indicating that the transcriptome sequencing data were accurate and reliable. Our results provide a theoretical basis for breaking the dormancy of aerial bulbs with low-temperature treatment to produce virus-free seedlings and increase the output and quality of garlic.
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Bradshaw, Laura D., Michael Barrett, and Charles G. Poneleit. "Physiological Basis for Differential Bentazon Susceptibility Among Corn (Zea mays) Inbreds." Weed Science 40, no. 4 (December 1992): 522–27. http://dx.doi.org/10.1017/s0043174500058070.
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Experiments were conducted to confirm the bentazon susceptibility of corn inbred GA209 and determine the physiological basis of this susceptibility. Bentazon (1.1 to 4.4 kg ha-1) plus crop oil concentrate (1% by vol) did not cause visible injury or dry weight loss of corn inbred B73 but caused 66 to 89% visual injury and 62 to 70% dry weight reduction of GA209 1 wk after treatment. Bentazon (2.2 kg ha-1) inhibited variable chlorophyll fluorescence decay in GA209 and B73 8 h after treatment. Variable fluorescence decay recovered in B73, but not in GA209, 96 h after treatment. Absorption and translocation of14C from14C-bentazon was greater in GA209 than B73 during a 48-h time course. Both inbreds converted bentazon to a polar metabolite which formed 6-hydroxybentazon upon hydrolysis with β-glucosidase. However, 63% of absorbed14C from14C-bentazon remained in the parent form in GA209 compared to 25% in B73 over a 72-h time course. A decreased ability of GA209 to metabolize bentazon may explain bentazon sensitivity of this inbred compared to B73.
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Amin, Mitra, Roohangiz Naderi, Shahram Sedaghathoor, and Sepideh Kalatehjari. "Pre and post-harvest effect of gibberellic acid and salicylic acid on cut branches of Asparagus umbellatus." Ornamental Horticulture 28, no. 3 (September 2022): 323–31. http://dx.doi.org/10.1590/2447-536x.v28i3.2467.
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Abstract Asparagus umbellatus is one of the most popular cut foliage plants that widely used in decorations and bouquets. However, there was a lack of information concerning Asparagus postharvest handling. Therefore, in this study, two growth regulators gibberellic acid (GA) and salicylic acid (SA) on concentrations of 0, 100, 200, and 400 μM were applied in two stages viz., pre and postharvest, separately and in combination. Experimental traits including; chlorophyll content, electrolyte leakage, solution uptake, microbial population, relative water content (%), malondialdehyde content, catalase, superoxide dismutase, and peroxidase activity along with plant vase life were evaluated. The results showed that the application of GA and SA lead to significantly extension of the vase life compared to the control. Vase life difference between control (9.34 days) and the superior treatment i.e. GA200+SA200 (14.07 days) was more than 50%. Also, the pre-harvest foliar application of GA and SA increased the vase life slightly compared to the application in vase solution. The extended vase life in the per-harvest experiment was obtained using SA100+GA100 and SA200+GA200 treatments.
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Temam, Stéphane, James F. Spicer, Carlos Gomez-Roca, Yann Berge, Jean-Pierre Jeannon, Jean-Charles Soria, Sophia Soehrman Brossard, et al. "Exploratory pharmacodynamics (PD) trial to investigate the mechanism of action of RG7160 (GA201), a novel dual-acting, monoclonal antibody (mAb) designed to enhance antibody-dependent cellular cytotoxicity (ADCC), compared with cetuximab (C) in neoadjuvant head and neck squamous cell carcinoma (HNSCC)." Journal of Clinical Oncology 30, no. 15_suppl (May 20, 2012): 5522. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.5522.
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5522 Background: GA201 efficacy was superior to C in orthotopic xenograft models in terms of activity and PD. In a phase I study, objective responses and long lasting stable disease were observed in heavily pre-treated patients (pts). Methods: HNSCC pts (T2-4, any N, M0) received i.v. neo-adjuvant 700/1400 mg GA201 or C (as per SPC), on D1 and 8. Tumor biopsies were taken at baseline (BL) and pre-surgery. The primary objective was determination of changes in tumor immune cell infiltration after treatment. Peripheral CD3+, CD16+, CD56+ cells, plasma cytokines, tumor EGFR and 18F-FDG-PET avidity were also studied. Results: To date, 39 pts (15/10 vs 14 pts for 700/1400 GA201 vs C, respectively) were evaluable for the primary objective and 4 pts are on-going. Patient characteristics at BL were as follows: median age, 57/62 vs 62 years; gender, 11/10 vs 12 male; tumor size ≤ 4 cm, 7/3 vs 3 pts. A greater proportion of pts receiving GA201 compared to C had metabolic tumor reduction (> 25% of SUVmax) (10/15 at 700 mg [1 pathological CR], 7/10 at 1400 mg GA201 vs 7/14 C pts) and symptomatic relief (6/12 at 700 mg, 6/7 at 1,400 mg GA201 vs 2/10 C pts). Table shows changes in PD markers. Conclusions: GA201 treatment, compared to C, exhibited more extensive tumor immune cell infiltration and a greater metabolic response. Consistent with the proposed mechanism of action of GA201, peripheral NK cells dropped and a unique cytokine profile was observed. The data support the immunomodulatory superiority of GA201 - a mAb designed to enhance ADCC compared to C. [Table: see text]
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Bradshaw, Laura D., Michael Barrett, and Charles G. Poneleit. "Inheritance of Bentazon Susceptibility in a Corn (Zea mays) Line." Weed Science 42, no. 4 (December 1994): 641–47. http://dx.doi.org/10.1017/s0043174500077080.
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Greenhouse experiments were conducted to determine if the inheritance of bentazon susceptibility in the corn inbred ‘GA209’ is a recessive single gene trait Bentazon was applied at 4.4 kg ai ha-1plus 1% by vol crop oil concentrate in all experiments. This treatment caused 96 and 30% visual injury and 86 and 50% dry weight loss for corn inbreds GA209 and ‘Ky226,’ respectively. Corn inbreds ‘B73,’ ‘T61,’ Mo17,’ ‘Pa91,’ and ‘CI66’ showed less than 18% injury and 10% dry weight loss and were considered tolerant of bentazon. Single crosses and reciprocal single crosses of GA209 with the other inbreds were considered bentazon tolerant with approximately 10% stunting and tissue necrosis and 20% dry weight reduction resulting from bentazon. Bentazon susceptibility was not maternally inherited. Apparent single recessive gene control of bentazon susceptibility of GA209 was observed for F2 and backcross segregations. However, subsequent analyses of F3 and selfed-backcross populations indicated that two genes, probably located on the same chromosome, controlled the bentazon susceptibility. Duplicate dominant epistasis provided the best fit for injury and dry weight reduction segregations in populations derived from the cross of inbreds GA209 and B73.
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Gebre, Endale, Peter Hedden, Karl Kunert, and Urte Schlüter. "Isolation, Characterization, and Expression of the Ricesd-1(GA20ox) Gene Ortholog inEragrostis tef." Journal of Crop Improvement 27, no. 5 (September 3, 2013): 507–27. http://dx.doi.org/10.1080/15427528.2013.797945.
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Boonkaew, Tippawan, Chareerat Mongkolsiriwatana, Ananya Vongvanrungruang, Kornsorn Srikulnath, and Surin Peyachoknagul. "Characterization of GA20ox genes in tall and dwarf types coconut (Cocos nucifera L.)." Genes & Genomics 40, no. 7 (March 23, 2018): 735–45. http://dx.doi.org/10.1007/s13258-018-0682-4.
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Mancao, Christoph, Lilla Di Scala, Paul Delmar, Stéphane Temam, Jean-Charles Soria, James F. Spicer, Mark McGurk, et al. "Correlative biomarker analysis of sequential tumor biopsies in a ph I mode of action (MoA) study in neoadjuvant head and neck squamous cell carcinoma (HNSCC) patients (pts) treated with RG7160 (GA201), a novel dual-acting, monoclonal antibody (mAb) designed to enhance antibody-dependent cellular cytotoxicity (ADCC), with cetuximab (C) as reference." Journal of Clinical Oncology 31, no. 15_suppl (May 20, 2013): 3035. http://dx.doi.org/10.1200/jco.2013.31.15_suppl.3035.
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3035 Background: GA201 is a novel humanized anti-epidermal growth factor receptor (EGFR) mAb with a dual MoA: glycoengineered to enhance ADCC on top of inhibition of EGFR signaling. In an open-label, multi-center trial of pts with HNSCC, an exploratory biomarker analysis of sequential tumor biopsies was performed to investigate the single/duplex marker correlation structure. Methods: Pts received 2 doses of 700 or 1,400 mg GA201 or C (day 1, 8). Tumor biopsies were taken at baseline (BL) and pre-surgery (day 15). Immunohistochemistry immune-cell counts (single/duplex markers), EGFR-pathway markers and intra-tumoral cytokines (LUMINEX) were assessed. Advanced exploratory statistical methods were used to analyse inter-relationship between BL and on treatment markers, and with response (as determined by FDG-PET). Results: All immune markers (single and duplex) presented highly heterogeneous median values at BL, but cluster analysis emphasized their strong inter-correlation. These markers were unrelated to the BL tumor EGFR and pERK expression. Strongest bivariate correlation was seen between (CD16, CD68), (CD3, 4, 8) and (CD4, NKp46). GA201 treatment induced positively correlated dynamic changes (chg) between (CD8, CD68), while C did so for (CD4, CD16) and (CD16, CD68). Strong and negative correlation between (CD56chg, PETchg) was seen only in pts treated with 1,400 mg GA201. Intra-tumoral cytokines like CXCL12 showed good correlation with BL CD3, 16 and 68 infiltration. Principle component analysis also confirmed a good association between most BL immune markers and was able to differentiate strongest PET responders in the 700 mg GA201 cohort. Conclusions: Multivariate statistical methods were used to demonstrate strong interdependencies between immune-effector markers and to highlight their promising associations with response to GA201 treatment, likely due to ADCC processes in the tumors. Clinical trial information: NCT01046266.
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Li, Zanzan, Jinyu Hu, Hang Tang, Liping Cao, Yuhang Chen, Qiaosheng Guo, and Changlin Wang. "Temperature and Photoperiod Change the Flowering Process in Prunella vulgaris by Inducing Changes in Morphology, Endogenous Hormones, Carbon/Nitrogen Metabolites, and Gene Expression." Journal of the American Society for Horticultural Science 147, no. 2 (March 2022): 73–81. http://dx.doi.org/10.21273/jashs05144-21.
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The spicas of Prunella vulgaris are widely used in the medical, beverage, and ornamental fields. Temperature and photoperiod are the two main ecological factors that determine the transformation of many plants from vegetative growth to reproductive growth. To explore the response of P. vulgaris flowering to temperature and photoperiod induction, we adopted vernalization long-day, vernalization short-day, nonvernalization long-day, and nonvernalization short-day treatments. The results showed that the morphology (total number of leaves, number of branches, number of leaves per branch, and branch length) of the vernalization treatment groups was significantly different from that of other nonvernalization groups, and the photosynthetic pigments, net photosynthetic rate, water use efficiency, stomatal conductance, intercellular CO2 concentration, and transpiration rate increased in the vernalization treatment group. However, the gibberellin 3 (GA3), indole-3-acetic acid and zeatin riboside (ZR) contents were significantly increased under the short-day treatments groups, and the results were the same for the expression of endogenous hormone synthesis genes, except for abscisic acid (ABA). The flowering-related genes soc1, elf3, svp, ga20ox, and cry1 were highly expressed under the vernalization short-day. Therefore, the induction of vernalization is more conducive to the increase in the photosynthetic rate. Temperature and photoperiod synergistically induced the synthesis and accumulation of starch, sugar, amino acids, and protein and affected the content of endogenous hormones and the expression of genes involved in their synthesis. GA3 and ZR had thresholds for their regulation of the flowering process in P. vulgaris, and high concentrations of ABA promoted flowering. Temperature and photoperiod coordinate the expression of the flowering-related genes soc1, elf3, svp, ga20ox, and cry1, thereby affecting the flowering process in P. vulgaris.
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Güzel, Melih, and Özlem Akpınar. "KOMAGATAEIBACTER HANSENII GA2016 İLE BAKTERİYEL SELÜLOZ ÜRETİMİ VE KARAKTERİZASYONU." GIDA / THE JOURNAL OF FOOD 42, no. 5 (2017): 620–33. http://dx.doi.org/10.15237/gida.gd17040.
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Cervantes-Ruiperez, Andres, Ben Markman, Salvatore Siena, Carles Pericay, Giuseppe Aprile, John A. Bridgewater, Antonio Cubillo, et al. "The GAIN-C study (BP25438): Randomized phase II trial of RG7160 (GA201) plus FOLFIRI, compared to cetuximab plus FOLFIRI or FOLFIRI alone in second-line KRAS wild type (WT) or mutant metastatic colorectal cancer (mCRC)." Journal of Clinical Oncology 30, no. 15_suppl (May 20, 2012): TPS3637. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.tps3637.
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TPS3637 Background: GA201 is a novel, dual-acting, humanized, glycoengineered IgG1 anti-EGFR monoclonal antibody, with enhanced antibody-dependent cellular cytotoxicity (ADCC) activity in combination with signal inhibition. GA201 demonstrates significantly enhanced in vitro/vivo activity compared to cetuximab (cet) both as a single agent and in combination with irinotecan, in both KRAS mutant and BRAF mutant models and promising clinical activity in ph I and neo-adjuvant trials (Paz Ares et al, JCO 2011) including KRAS mutant mCRC. A randomized ph II program was launched: one study in NSCLC and GAIN-C in mCRC (NCT01326000), which is presented here. Methods: Main inclusion criteria are progression on 1L containing oxaliplatin, ECOG 0-1, and adequate hematological and liver function. Main exclusion criteria: prior anti-EGFR treatment. A total of 160 patients in 2L mCRC (stratified for EGFR expression, disease progression before or after 6 months after starting 1L, prior treatment with bevacizumab Y vs N) will be randomized to receive either GA201 (day 1, 8 of cycle 1 then q2W) or cet (qW) + FOLFIRI q2W (KRAS WT) or to receive GA201+ FOLFIRI or FOLFIRI alone (KRAS mutant). Collection of archival tumor plus a mandatory fresh tumor biopsy at baseline were implemented because ph I data showed that EGFR expression is not concordant between the two specimen types and to optimize assessment of potential immune related biomarkers. The fresh tumor biopsy will be centrally analyzed for EGFR (immunohistochemistry) and KRAS status. Primary objective is progression free survival; secondary endpoints are to define objective response rates, the safety profile, pharmacokinetics and pharmacodynamics. A comprehensive biomarker program (blood and tumor), mainly immune-phenotyping, immunohistochemistry in tumor samples (Ventana) and immune functional tests (including adaptive responses) were set up to investigate potential predictive biomarkers and the mode of action of GA201. Study is ongoing worldwide in 9 countries with the safety run-in phase completed in Nov 2011. Recruitment is planned to be completed by end of April 2012.
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Spicer, James F., Enriqueta Felip, Lionel Bosquée, Vanesa Gregorc, Iker Lopez Calderero, Pablo Martinez, Ana Montes, et al. "GAIN-(L): Efficacy and biomarker findings of RG7160 (GA201), a novel, dual-acting monoclonal antibody (mAb) designed to enhance antibody-dependent cellular cytotoxicity (ADCC), in combination with first-line cisplatin and pemetrexed in metastatic nonsquamous NSCLC." Journal of Clinical Oncology 30, no. 15_suppl (May 20, 2012): 7544. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.7544.
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7544 Background: GA201, a humanized, engineered IgG1 anti-Epidermal Growth Factor Receptor (EGFR) mAb designed to enhance ADCC, has shown promising clinical activity in phase I and in the neoadjuvant treatment of head and neck cancer. This phase Ib study (NCT01185847) aimed to determine the safety, pharmacokinetics (PK), activity and recommended phase II dose (RP2D) of GA201 in combination with chemotherapy in non-squamous NSCLC. Methods: Successive cohorts received GA201 1000 mg or 1400 mg (IV d1, d8 then 2-weekly (q2W)) in combination with chemotherapy at standard doses. Data cut off was 7 months after enrolling the last patient. Results: 14 patients (4 female) with performance status 0-1 were enrolled. No maximum tolerated dose was reached. Most common adverse events (AEs – all grades) included rash (100%), hypomagnesaemia (71%), infusion-related reactions (64%), mucosal inflammation (57%) and anemia (50%). AEs of ≥ grade 3 included rash (71%), skin fissure (21%), dry skin (14%), paronychia (14%), and asthenia (14%). Median timeto improvement of rash grade 3 was 11 days. AEs led to dose reduction for 4 patients and discontinuation for 1 patient. There were 6 confirmed partial responses (43%, 5 in 1400 mg cohort) and 7 patients (50%) with stable disease >=9 weeks. Duration of response ranged between 5 and 42 weeks (3 patients still ongoing). Preliminary biomarker analysis shows a correlation between tumor-infiltrating CD16+ immune cells and target lesion shrinkage at first tumor assessment [R(spear)=-0.65 (p=0.02)]; no apparent correlation between EGFR H-score and response was found. PK data supports 1400 mg as the RP2D (d1, d8 then q2W). Conclusions: The RP2D of GA201 in combination with chemotherapy was established to be 1400 mg. The incidence of EGFR associated rash was high and guidelines to reduce its severity were implemented with a noted improvement in tolerability. Promising antitumor activity was observed. Biomarker data support the mode of action of GA201 via ADCC. A randomized phase II trial of this combination is ongoing and fully recruited.
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Santoso, T. J., K. R. Trijatmiko, S. N. Char, B. Yang, and K. Wang. "Targeted mutation of GA20ox-2 gene using CRISPR/Cas9 system generated semi-dwarf phenotype in rice." IOP Conference Series: Earth and Environmental Science 482 (May 29, 2020): 012027. http://dx.doi.org/10.1088/1755-1315/482/1/012027.
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Yoshida, Hideki, Sayaka Takehara, Masaki Mori, Reynante Lacsamana Ordonio, and Makoto Matsuoka. "Evolution of GA Metabolic Enzymes in Land Plants." Plant and Cell Physiology 61, no. 11 (October 13, 2020): 1919–34. http://dx.doi.org/10.1093/pcp/pcaa126.
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Abstract Gibberellins (GAs) play key roles in various developmental processes in land plants. We studied the evolutionary trends of GA metabolic enzymes through a comprehensive homology search and phylogenetic analyses from bryophytes to angiosperms. Our analyses suggest that, in the process of evolution, plants were able to acquire GA metabolic enzymes in a stepwise manner and that the enzymes had rapidly diversified in angiosperms. As a good example of their rapid diversification, we focused on the GA-deactivating enzyme, GA 2-oxidase (GA2ox). Although the establishment of a GA system first occurred in lycophytes, its inactivation system mediated by GA2oxs was established at a much later time: the rise of gymnosperms and the rise of angiosperms through C19-GA2ox and C20-GA2ox development, respectively, as supported by the results of our direct examination of their enzymatic activities in vitro. Based on these comprehensive studies of GA metabolic enzymes, we discuss here that angiosperms rapidly developed a sophisticated system to delicately control the level of active GAs by increasing their copy numbers for their survival under different challenging environments.
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Junttila, O., R. W. King, A. Poole, G. Kretschmer, R. P. Pharis, and L. T. Evans. "Regulation in Lolium temulentum of the Metabolism of Gibberellin A20 and Gibberellin A1 by 16,17-Dihydro GA5 and by the Growth Retardant, LAB 198 999." Functional Plant Biology 24, no. 3 (1997): 359. http://dx.doi.org/10.1071/pp96031.
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The ring D-modified gibberellin [GA], 16,17-dihydro GA5, can retard stem growth in Lolium temulentum L. while promoting flowering (Evans et al., 1994, Planta193, 107–114). Using [1,2,3-3 H]GA20 to study the final biosynthetic step to GA1 (a known effector of shoot elongation in higher plants), it was shown that C-3b-hydroxylation of GA20 to GA1 is blocked by 16,17-dihydro GA5 but is little affected by GA5. Another late-stage biosynthetic inhibitor, the acylcyclohexanedione, LAB 198 999, also blocked GA1 formation. Furthermore, endogenous levels of GA20 built up after application of 16,17-dihydro GA5. Consequently, growth retardation by 16,17-dihydro GA5 and LAB 198 999 is likely to be the result of their inhibition of GA20 3b-hydroxylation to GA1. Another fate for GA20 in Lolium is its C-2b-hydroxylation to growth-inactive GA29. This conversion was also inhibited by 16,17-dihydro GA5 but less so by LAB 198 999. The analogous step involving 2b-hydroxylation of GA1 to GA8 appeared to be insensitive to either growth retardant. When [3H]GA20 was injected into the cavity within the young intact sheathing leaves, there was an appreciable metabolism of this GA20 to GA1 and thence to GA8 (ca 10% and 30% respectively within 5 h). For excised shoot tips, however, [3H]GA20 was converted rapidly and virtually completely to GA29 in 3–5 h. Interestingly, with these excised shoot tips, GA3 and GA5 as well as 16,17-dihydro GA5 when applied via the agar strongly inhibited 2b-hydroxylation of GA20 to GA29. In contrast, while 16,17-dihydro GA5 blocked GA20 metabolism to GA29 in intact sheath/stem tissue, this conversion was not inhibited by GA5. These differences in structural specificity for GAs which inhibit 2b-hydroxylation as opposed to 3b-hydroxylation are in accordance with these two Ring-A hydroxylation steps being catalysed by different enzymes. Finally, the differences in GA20 metabolism between intact versus excised tissue raise the possibility that tissue wounding with excision enhanced the activity of the GA20 2b-hydroxylase(s).
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Tan, Z. G., and Y. L. Qian. "Light Intensity Affects Gibberellic Acid Content in Kentucky Bluegrass." HortScience 38, no. 1 (February 2003): 113–16. http://dx.doi.org/10.21273/hortsci.38.1.113.
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Turfgrasses grown under low light conditions generally exhibit increased shoot elongation. Gibberellic acids (GAs), GA1 in particular, promote stem elongation in grass species. GA20 is the immediate precursor of GA1. However, a direct quantitative measurement of GA1 and GA20 has not been reported for turfgrass under different light intensities. This study was conducted in a greenhouse to quantify the endogenous levels of GA1 and GA20 of `KenblueTimes', `Livingston', and `NuGlade' Kentucky bluegrass (Poa pratensis L.) under two light intensities with and without trinexapacethyl (TE) application. GA1 and GA20 content in leaf tissue were analyzed using gas chromatography-mass spectrometry with deuterium-labeled GA1 and GA20 as internal standards. Light reduction of 73% under greenhouse conditions increased GA1 by 44% to 47% and GA20 by 16% to 50%. `NuGlade' had a GA1 content 20% lower than that of `Kenblue', suggesting that the dwarf characteristics of `NuGlade' may be related to its low GA1 content. The application of TE (0.1 kg·ha-1) reduced GA1 concentration by 47%, but increased GA20 concentration by 146%, supporting the contention that TE inhibited GA1 biosynthesis by blocking the conversion of GA20 to GA1. Chemical names used: 4-(cyclopropyl- -hydroxy-methylene)-3,5-dioxo-cyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl); gibberellic acid (GA).
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Studzinska, Aneta K., David S. Gardner, James D. Metzger, David Shetlar, Robert Harriman, and T. Karl Danneberger. "The Effect of PcGA2ox Overexpression on Creeping Bentgrass (Agrostis stolonifera L.): Performance under Various Light Environments." HortScience 47, no. 2 (February 2012): 280–84. http://dx.doi.org/10.21273/hortsci.47.2.280.
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Turf grown in shade exhibits increased stem elongation. Dwarfism could improve turfgrass quality by reducing elongation. The purpose of this study was to examine the effect of GA2-oxidase (GA2ox) overexpression on creeping bentgrass (Agrostis stolonifera L.) performance under restricted light conditions and low mowing heights. Greenhouse studies were conducted at The Ohio State University, Columbus, OH, from 1 Sept. to 31 Oct. in both 2008 and 2009. Two experimental lines, Ax6548 and Ax6549, transformed with CP4 EPSPS and PcGA2ox gene; and a nontransformed control (NTC) was subjected to four light environments: full sun, reduced red to far red light ratio (R:FR), neutral shade [reduced photosynthetic photon flux (PPF)], and canopy shade (reduced PPF and R:FR). Turf was evaluated every 10 days for color and percent coverage. GA2ox overexpression resulted in darker green color in both transgenic lines under all light treatments as compared with NTC plants. No differences in overall turfgrass coverage were noted in full sun conditions among the lines. A significant decrease in turf coverage occurred for all shade treatments regardless of line. However, Ax6549 decreased the least. Overall data indicated that GA2ox overexpression can improve quality of turfgrass under reduced light conditions.
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Xu, Congping, Ying Zhang, Qiang Han, and Xiangyang Kang. "Molecular Mechanism of Slow Vegetative Growth in Populus Tetraploid." Genes 11, no. 12 (November 27, 2020): 1417. http://dx.doi.org/10.3390/genes11121417.
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Tetraploid plants often have altered rates of vegetative growth relative to their diploid progenitors. However, the molecular basis for altered growth rates remains a mystery. This study reports microRNA (miRNA) and gene expression differences in Populus tetraploids and counterpart diploids using RNA and miRNA sequencing. The results showed that there was no significant difference between young leaves in the expression of vegetative growth-related miRNAs. However, as leaves aged, the expression of auxin- and gibberellin-related miRNAs was significantly upregulated, while the expression of senescence-related miRNAs was significantly downregulated. The dose effect enhanced the negative regulation of the target genes with ARFs, GA20ox, GA3ox, and GAMYB being downregulated, and TCP and NAC being upregulated. As a result, the chloroplast degradation of tetraploid leaves was accelerated, the photosynthetic rate was decreased, and the synthesis and decomposition ability of carbohydrate was decreased.
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Ito, Kouichi, Naoko Ito, Sudhir K. Yadav, Shradha Suresh, Yong Lin, and Suhayl Dhib-Jalbut. "Effect of switching glatiramer acetate formulation from 20 mg daily to 40 mg three times weekly on immune function in multiple sclerosis." Multiple Sclerosis Journal - Experimental, Translational and Clinical 7, no. 3 (July 2021): 205521732110323. http://dx.doi.org/10.1177/20552173211032323.
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Background Many RRMS patients who had been treated for over 20 years with GA 20 mg/ml daily (GA20) switched to 40 mg/ml three times-a-week (GA40) to reduce injection-related adverse events. Although GA40 is as effective as GA20 in reducing annualized relapse rate and MRI activity, it remains unknown how switching to GA40 from GA20 affects the development of pathogenic and regulatory immune cells. Objective To investigate the difference in immunological parameters in response to GA20 and GA40 treatments. Methods We analyzed five pro-inflammatory cytokines (IL-1β, IL-23, IL-12, IL-18, TNF-α), and three anti-inflammatory/regulatory cytokines (IL-10, IL-13, and IL-27) in serum. In addition, we analyzed six cytokines (IFN-γ, IL-17A, GM-CSF, IL-10, IL-6, and IL-27) in cultured PBMC supernatants. The development of Th1, Th17, Foxp3 Tregs, M1-like, and M2-like macrophages were examined by flow cytometry. Samples were analyzed before and 12 months post switching to GA40 or GA20. Results Pro- and anti-inflammatory cytokines were comparable between the GA40 and GA20 groups. Development of Th1, Th17, M1-like macrophages, M2-like macrophages, and Foxp3 Tregs was also comparable between the two groups. Conclusions The immunological parameters measured in RRMS patients treated with GA40 three times weekly are largely comparable to those given daily GA20 treatment.
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Çayan, Selin, Gölge Sarıkamış, Canan Yüksel Özmen, Umut Kibar, Eren Özden, and Ali Ergül. "The influence of exogenous gibberellic acid (GA3) and 24-epibrassinolide (24-EpiBL) on seed germination and the expression of genes involved in GA and BR synthesis/signalling in pepper (Capsicum annuum L.)." Acta Scientiarum Polonorum Hortorum Cultus 20, no. 5 (October 29, 2021): 15–23. http://dx.doi.org/10.24326/asphc.2021.5.2.
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Gibberellins (GAs) and brassinosteroids (BRs) are the plant hormones involved in various physiological processes including seed germination. In this study, the effects of exogenous gibberellic acid (GA3) and 24-epibrassinolide (24-EpiBL) treatments on the expression of key genes involved in GA and BR syntheis/signalling during seed germination were investigated in pepper (Capsicum annuum L).
The expressions of BES1 and BRI1 involved in BR synthesis/signalling pathway as well as GA3OX1 and GA20OX1 associated with gibberellic acid biosynthesis in plants were determined. Exogenous GA3 treatments increased BES1 expression and the highest increase was determined with 10⁻⁸ M BR + 100 µM GA3 (P<0.05). On the contrary, the expression of BRI1 gene was significantly decreased by 10-8 M BR + 100 µM GA3 (P<0.05). The expression of GA3OX1 gene was induced with BR and GA3 treatments (P<0.05). GA20OX1 gene expression was generally higher compared to the expression of GA3OX1 and significantly increased by the GA3 treatments. Our findings are expected to bring an insight to the influence of BRs during seed germination together with the expression of associated genes.
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Delord, Jean-Pierre, Josep Tabernero, Rocio Garcia-Carbonero, Andres Cervantes-Ruiperez, Carlos Alberto Gomez-Roca, Yann Berge, Jaume Capdevila, et al. "Long-term efficacy and pharmacodynamic parameter analysis in pretreated KRAS-mutant metastatic colorectal carcinoma (mCRC) patients treated with RG7160 (GA201), an antibody-dependent cellular cytotoxicity (ADCC)-enhanced monoclonal anti-EGFR antibody." Journal of Clinical Oncology 31, no. 4_suppl (February 1, 2013): 379. http://dx.doi.org/10.1200/jco.2013.31.4_suppl.379.
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379 Background: EGFR-positive, KRAS-mutant mCRC patients (pts) do not benefit from anti-EGFR treatment. In this pt population we investigated the efficacy of single-agent GA201, a novel dual acting, anti-EGFR antibody which was glycoengineered to enhance ADCC on top of signaling blockage. This stimulation of immune effector cells may improve long term clinical outcomes. Methods: In an open-label, multicenter, non-randomized study, KRAS-mutant mCRC pts (1-2 prior chemotherapy lines) were treated with GA201 (1400 mg on day 1 and 8 then by 1400 mg q2W). The primary endpoint was to investigate tumor response. Here we report response rates, overall survival (OS) and pharmacodynamics analyses from archival, pre- and on-treatment biopsies and blood samples. Results: 25 pts received a median of 5 GA201 infusions (range 2–24), for up to 414 days. Median overall survival was 9.3 months (range 1.2 – 21.2). Best overall response was stable disease (40% of patients at 8 weeks), which was maintained in 24% of pts at 16 weeks, in 2 patients (8%) at 24 weeks and 1 pt (4%) at 42 weeks. Treatment-related adverse events were all manageable with rash (20% grade3), hypomagnesaemia (20% g3/4) and infusion-related reactions (4% g3) being the most common adverse events; none led to discontinuation or dose reduction. Comparison of pre- and post-treatment tumor biopsies evaluable for 11 pts revealed that tumor-infiltrating cell counts increased notably after one cycle of therapy (median composite immune reactive score of 1491 vs 898 cells/mm3 at baseline). In addition, it was noted that EGFR H-score in baseline tumor biopsies was notably higher than in archival tumors (median [range] 52 [13–161] vs 3 [1–81], respectively). High tumor immune cell infiltration at baseline might be associated with better treatment outcome and long-term survival. Conclusions: Encouraging OS is achieved with GA201 monotherapy in patients with KRAS-mutant tumors. The pharmacodynamics analyses support the hypothesis of triggering an enhanced long term immune response in this pretreated patient population. Clinical trial information: NCT00721266.
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Green, Jerry M. "Differential Tolerance of Corn (Zea mays) Inbreds to Four Sulfonylurea Herbicides and Bentazon." Weed Technology 12, no. 3 (September 1998): 474–77. http://dx.doi.org/10.1017/s0890037x00044171.
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Nine corn inbreds were selected from a test on 250 inbreds based on distinctly different response to herbicides. These inbreds showed up to 50,000-fold differences, which varied by inbred and herbicide. Only the inbred GA209 was sensitive to bentazon and the four sulfonylurea herbicides. GA209 and B90 were the most sensitive inbreds to the sulfonylurea herbicides. F2R was generally the most tolerant inbred. The pattern of herbicide tolerance varied greatly. For example, the relative tolerance of F2 to thifensulfuron was 12-fold more than to rimsulfuron while Mo17 was 56-fold more tolerant to rimsulfuron than thifensulfuron. F2 was fivefold more tolerant of chlorsulfuron than chlorimuron, whereas B80 was 100-fold the reverse. These inbreds provide a small subset of varieties to evaluate the large and inherent differences in herbicide tolerance of corn.
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Jung, Yu Jin, Jong Hee Kim, Hyo Ju Lee, Dong Hyun Kim, Jihyeon Yu, Sangsu Bae, Yong-Gu Cho, and Kwon Kyoo Kang. "Generation and Transcriptome Profiling of Slr1-d7 and Slr1-d8 Mutant Lines with a New Semi-Dominant Dwarf Allele of SLR1 Using the CRISPR/Cas9 System in Rice." International Journal of Molecular Sciences 21, no. 15 (July 31, 2020): 5492. http://dx.doi.org/10.3390/ijms21155492.
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The rice SLR1 gene encodes the DELLA protein (protein with DELLA amino acid motif), and a loss-of-function mutation is dwarfed by inhibiting plant growth. We generate slr1-d mutants with a semi-dominant dwarf phenotype to target mutations of the DELLA/TVHYNP domain using CRISPR/Cas9 genome editing in rice. Sixteen genetic edited lines out of 31 transgenic plants were generated. Deep sequencing results showed that the mutants had six different mutation types at the target site of the TVHYNP domain of the SLR1 gene. The homo-edited plants selected individuals without DNA (T-DNA) transcribed by segregation in the T1 generation. The slr1-d7 and slr1-d8 plants caused a gibberellin (GA)-insensitive dwarf phenotype with shrunken leaves and shortened internodes. A genome-wide gene expression analysis by RNA-seq indicated that the expression levels of two GA-related genes, GA20OX2 (Gibberellin oxidase) and GA3OX2, were increased in the edited mutant plants, suggesting that GA20OX2 acts as a convert of GA12 signaling. These mutant plants are required by altering GA responses, at least partially by a defect in the phytohormone signaling system process and prevented cell elongation. The new mutants, namely, the slr1-d7 and slr1-d8 lines, are valuable semi-dominant dwarf alleles with potential application value for molecule breeding using the CRISPR/Cas9 system in rice.
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Ferrero, Lucía V., Ivana L. Viola, Federico D. Ariel, and Daniel H. Gonzalez. "Class I TCP Transcription Factors Target the Gibberellin Biosynthesis Gene GA20ox1 and the Growth-Promoting Genes HBI1 and PRE6 during Thermomorphogenic Growth in Arabidopsis." Plant and Cell Physiology 60, no. 8 (July 11, 2019): 1633–45. http://dx.doi.org/10.1093/pcp/pcz137.
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Abstract Plants respond to a rise in ambient temperature by increasing the growth of petioles and hypocotyls. In this work, we show that Arabidopsis thaliana class I TEOSINTE BRANCHED 1, CYCLOIDEA, PCF (TCP) transcription factors TCP14 and TCP15 are required for optimal petiole and hypocotyl elongation under high ambient temperature. These TCPs influence the levels of the DELLA protein RGA and the expression of growth-related genes, which are induced in response to an increase in temperature. However, the class I TCPs are not required for the induction of the auxin biosynthesis gene YUCCA8 or for auxin-dependent gene expression responses. TCP15 directly targets the gibberellin biosynthesis gene GA20ox1 and the growth regulatory genes HBI1 and PRE6. Several of the genes regulated by TCP15 are also targets of the growth regulator PIF4 and show an enrichment of PIF4- and TCP-binding motifs in their promoters. PIF4 binding to GA20ox1 and HBI1 is enhanced in the presence of the TCPs, indicating that TCP14 and TCP15 directly participate in the induction of genes involved in gibberellin biosynthesis and cell expansion by high temperature functionally interacting with PIF4. In addition, overexpression of HBI1 rescues the growth defects of tcp14 tcp15 double mutants, suggesting that this gene is a major outcome of regulation by both class I TCPs during thermomorphogenesis.
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Ross, John J., Sandra E. Davidson, Carla M. Wolbang, Emma Bayly-Stark, Jennifer J. Smith, and James B. Reid. "Developmental regulation of the gibberellin pathway in pea shoots." Functional Plant Biology 30, no. 1 (2003): 83. http://dx.doi.org/10.1071/fp02108.
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To investigate gibberellin (GA) biosynthesis in mature tissue of pea (Pisum sativum L.) in the absence of potentially GA-producing meristematic tissue we grafted wild-type scions to rootstocks of the GA-deficient ls-1 mutant and later decapitated the shoot. After 2 d, decapitated shoots contained as much GA19 (a precursor of the bioactive GA1) as comparable tissue from intact plants, even though applied [14C]GA19 was metabolised rapidly during this time. These results show that the pool size of endogenous GA19 was maintained, probably by de novo GA19 synthesis. We also found that the LS gene, which catalyses an early step in GA biosynthesis, is expressed in mature tissue, as are the shoot-expressed GA 20-oxidase and GA 3-oxidase genes. Nevertheless, mature tissue contained very low levels of GA1 and GA20 compared with immature tissue. Levels of GA19, GA29 and GA8 were less affected by tissue age. Metabolism studies using 14C-labelled GAs indicated that mature tissue rapidly converted GA19 to GA20 and GA20 to GA1; the latter step was promoted by IAA. However, the 2-oxidation steps GA1 to GA8, GA20 to GA29 and GA29 to GA29-catabolite appear to proceed very rapidly in mature tissue (regardless of IAA content), and we suggest this is the reason why GA1 and GA20 do not accumulate. This is supported by the high level of expression of a key GA 2-oxidase gene in mature tissue.
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Modjtahedi, Helmout, and Suzanne Eccles. "GA201: A Novel Humanized and Glycoengineered Anti-EGFR Antibody—Letter." Clinical Cancer Research 20, no. 4 (February 15, 2014): 1053–54. http://dx.doi.org/10.1158/1078-0432.ccr-13-2124.
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Gerdes, Christian A., and Pablo Umaña. "GA201: A Novel Humanized and Glycoengineered Anti-EGFR Antibody—Response." Clinical Cancer Research 20, no. 4 (February 15, 2014): 1055. http://dx.doi.org/10.1158/1078-0432.ccr-13-2699.
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Song, Qiling, Ke Ji, Wenjuan Mo, Linkai Wang, Le Chen, Ling Gao, Wenfang Gong, and Deyi Yuan. "Dynamics of sugars, endogenous hormones, and oil content during the development of Camellia oleifera fruit." Botany 99, no. 8 (August 2021): 515–29. http://dx.doi.org/10.1139/cjb-2021-0019.
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Camellia oleifera Abel (‘Huashuo’) is an important woody oil species with high economic value. Low yield is the main factor restricting the rapid development of the tea-oil industry. The dynamics of sugars, oil, endogenous hormones, and the genes involved in these pathways, as well as the correlation with oil synthesis-related factors in Huashuo, were investigated. The results showed that oil content was positively correlated with sucrose and starch content but was negatively correlated with reducing sugar content. Pyruvate kinase (PK) and fructose-1,6-bisphosphate aldolase (FBA) of the glycolysis pathway could be beneficial for oil biosynthesis. Higher levels of acetyl CoA carboxylase (ACC), stearoyl-ACP desaturase (SAD), and WRINKLED1 (WRI1), as well as lower levels of omega-6 fatty acid desaturase 2 (FAD2) and lipoxygenase 5 (LOX5) could be responsible for the oil production. The higher expression of gibberellin 20 oxidase (GA20ox), lower expression of gibberellic acid insensitive (GAI), and the increase in 9-cis-epoxycarotenoid dioxygenase (NCED) at the mRNA level could contribute to oil accumulation. The results of this study could provide a reference for increasing the yield of plants related to Huashuo.
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Li, Wenqi, Yubing Yong, Yue Zhang, and Yingmin Lyu. "Transcriptional Regulatory Network of GA Floral Induction Pathway in LA Hybrid Lily." International Journal of Molecular Sciences 20, no. 11 (May 31, 2019): 2694. http://dx.doi.org/10.3390/ijms20112694.
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Background: The LA hybrid lily ‘Aladdin’ has both excellent traits of Longiflorum hybrids and Asiatic hybrids—such as big and vivid flower, strong stem, high self-propagation coefficient, and shorter low temperature time required to release bulb dormancy in contrast to Oriental hybrids. A genome-wide transcriptional analysis using transcriptome RNA-Seq was performed in order to explore whether there is a gibberellin floral induction pathway in the LA hybrid lily. Subsequently, gene co-expression network analysis was used to analyze the possible interactions of key candidate genes screened from transcriptome data. At the same time, a series of physiological, biochemical, and cultivation tests were carried out. Results: The content of five endogenous hormones changed sharply in the shoot apex during the treatment of 200 mg/L exogenous gibberellin and the ratio of ABA/GA3 dropped and stayed at a lower level after 4 hours’ treatment from the higher levels initially, reaching a dynamic balance. In addition, the metabolism of carbohydrates in the bulbs increase during exogenous gibberellin treatment. A total of 124,041 unigenes were obtained by RNA-seq. With the transcriptome analysis, 48,927 unigenes and 48,725 unigenes respectively aligned to the NR database and the Uniprot database. 114,138 unigenes, 25,369 unigenes, and 19,704 unigenes respectively aligned to the COG, GO, and KEGG databases. 2148 differentially expression genes (DEGs) were selected with the indicators RPKM ≥ 0, FDR ≤ 0.05 and |log2(ratio)| ≥ 2. The number of the upregulated unigenes was significantly more than the number of the downregulated unigenes. Some MADS-box genes related to flowering transformation—such as AGL20, SOC1, and CO—were found to be upregulated. A large number of gibberellin biosynthesis related genes such as GA2ox, GA3ox, GA20ox, Cytochrome P450, CYP81, and gibberellin signal transduction genes such as DELLA, GASA, and GID1 were significantly differentially expressed. The plant hormones related genes such as NCED3 and sugar metabolism related genes such as α-amylase, sucrose synthase hexokinase, and so on were also found expressing differentially. In addition, stress resistance related genes such as LEA1, LEA2, LEA4, serine/threonine protein kinase, LRR receptor-like serine/threonine protein kinase, P34 kinase, histidine kinase 3 and epigenetic related genes in DNA methylation, histone methylation, acetylation, ubiquitination of ribose were also found. Particularly, a large number of transcription factors responsive to the exogenous gibberellin signal including WRKY40, WRKY33, WRKY27, WRKY21, WRKY7, MYB, AP2/EREBP, bHLH, NAC1, NAC2, and NAC11 were found to be specially expressing. 30 gene sequences were selected from a large number of differentially expressed candidate genes for qRT-PCR expression verification (0, 2, 4, 8, and 16 h) and compared with the transcriptome expression levels. Conclusions: 200mg/L exogenous GA3 can successfully break the bulb’s dormancy of the LA hybrid lily and significantly accelerated the flowering process, indicating that gibberellin floral induction pathway is present in the LA lily ‘Aladdin’. With the GCNs analysis, two second messenger G protein-coupled receptor related genes that respond to gibberellin signals in the cell were discovered. The downstream transport proteins such as AMT, calcium transport ATPase, and plasma membrane ATPase were also discovered participating in GA signal transduction. Transcription factors including WRKY7, NAC2, NAC11, and CBF specially regulated phosphorylation and glycosylation during the ubiquitination degradation process of DELLA proteins. These transcription factors also activated in abscisic acid metabolism. A large number of transcription factors such as WRKY21, WRKY22, NAC1, AP2, EREB1, P450, and CYP81 that both regulate gibberellin signaling and low-temperature signals have also been found. Finally, the molecular mechanism of GA floral induction pathway in the LA hybrid lily ‘Aladdin’ was constructed.
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Rajasekaran, K., C. M. Sickler, R. L. Brown, J. W. Cary, and D. Bhatnagar. "Evaluation of resistance to aflatoxin contamination in kernels of maize genotypes using a GFP-expressing Aspergillus flavus strain." World Mycotoxin Journal 6, no. 2 (May 1, 2013): 151–58. http://dx.doi.org/10.3920/wmj2012.1497.
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Resistance or susceptibility of maize inbreds to infection by Aspergillus flavus was evaluated by the kernel screening assay. A green fluorescent protein-expressing strain of A. flavus was used to measure fungal spread and aflatoxin levels in real-time following fungal infection of kernels. Among the four inbreds tested, MI82 showed the most resistance and Ga209 the least. TZAR101 was also resistant to fungal infection, whereas Va35 was susceptible to fungal infection. However, Va35 produced lower aflatoxin levels compared to the susceptible line Ga209. Fluorescence microscopy indicated that the site of entry of the fungus into the kernel was consistently through the pedicel. Entry through the pericarp was never observed in undamaged kernels. In view of these results, incorporation or overexpression of antifungal proteins should be targeted to the pedicel and basal endosperm region in developing kernels. Once the fungus has entered through the pedicel, it spreads quickly through the open spaces between the pericarp and the aleurone layer, ultimately colonising the endosperm and scutellum and, finally, the embryo. A clear correlation was established between fungal fluorescence and aflatoxin levels. This method provides a quick, reliable means of evaluating resistance to A. flavus in undamaged kernels and provides breeders with a rapid method to evaluate maize germplasm.
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Maki, Sorua L., Melissa B. Riley, and Nihal C. Rajapakse. "Gibberellin Status of Spectral Filter-grown Chrysanthemum Plants." HortScience 31, no. 4 (August 1996): 581c—581. http://dx.doi.org/10.21273/hortsci.31.4.581c.
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Endogenous gibberellins of chrysanthemum [Dendranthema ×grandiflorum (Ramat)] cv. Bright Golden Anne were characterized in apices from plants grown under control and CuSO4 spectral filters. Expanding shoots were separated into young expanding leaves and apices. Methanolic extracts of young expanding leaves were purified by solvent partitioning, PVPP column chromatography and reversed-phase high performance liquid chromatography. Two bioactive regions corresponding to the HPLC retention times of GA1 and GA19 standards were detected in fractions using the recently-developed non-dwarf rice bioassay. Di-deuterated internal standards of GA12, GA53, GA19, GA20, and GA1 were added to similar extracts of shoot apices. The presence of endogenous GA53, GA19, GA20, and GA1 in chrysanthemum apices was confirmed by isotope dilution using gas chromatography-mass spectrometry-selected ion monitoring and Kovats retention indices. In a preliminary quantification study, GA20 and GA1 levels were found to be higher in apices from plants grown under control filters while GA19 levels were higher in apices grown under CuSO4 filters. The possibility that light transmitted through CuSO4 filters alters gibberellin levels in shoot apices is discussed.
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Maki, Sonja L., Sriyani Rajapakse, Robert E. Ballard, and Nihal C. Rajapakse. "Role of Gibberellins in Chrysanthemum Growth under Far Red Light-deficient Greenhouse Environments." Journal of the American Society for Horticultural Science 127, no. 4 (July 2002): 639–43. http://dx.doi.org/10.21273/jashs.127.4.639.
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Plants grown in far red (FR) light deficient environments are typically shorter because of short internodes, resembling plants treated with GA biosynthesis inhibitors. The role of GAs in the reduction of stem elongation of `Bright Golden Anne' chrysanthemum [Dendranthem ×grandiflora (Ramat.) Kitam. (syn. Chrysanthemum ×morifolium Ramat.)] grown in FR light deficient (-FR) environment was investigated by following the response of chrysanthemums grown in - FR environment to exogenous application of GA1, GA19, or GA20, and the metabolism of GA12 and GA19 in -FR or +FR environment. FR light deficient environment resulted in 25% to 30% shorter plants than in +FR environment. Final height of GA1- and GA20-treated plants followed a quadratic pattern while that of GA19 treated plants followed a linear pattern as the dosage increased from 0 to 50 μg/apex. The response to GA1 was the greatest followed by GA20 and GA19, regardless of the light environment. Application of GA1 (50 μg/apex) increased final height by 65% compared with no GA (0 μg/apex) application under either +FR or -FR light environment, suggesting the response to GA1, which is the active form, remained the same. Responses to GA19 and GA20 declined under -FR light. [14 C]GA12 and [14C]GA19 metabolized slowly in the -FR environment suggesting that the turnover of GAs may have caused in part the lower response to GA19. Although metabolism of GA1 under -FR environments was not investigated, observations with GA1 application experiments support that -FR environment may have enhanced inactivation of GA1. Chemical name used: gibberellic acid (GA).
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Croker, Steve J., Peter Hedden, and Wilhelm Rademacher. "185 Effects of Prohexadione-Ca on Gibberellin Levels in Young Apple Shoots." HortScience 35, no. 3 (June 2000): 422D—422. http://dx.doi.org/10.21273/hortsci.35.3.422d.
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Prohexadione-Ca (BAS 125 W) is a new growth retardant for the inhibition of excessive vegetative growth in apple and other plant species. From work with enzyme preparations, it is known that prohexadione-Ca mimics 2-oxoglutaric acid, the co-substrate of dioxygenases, which catalyze late steps in gibberellin (GA) biosynthesis. As a result, the formation of growth-active GAs is reduced. In order to have a better understanding of its effects in intact plants, we have analyzed the GA status of treated and untreated apple plantlets. In a typical experiment, the following results were obtained: Plants (cv. Jonagold on M9 at 19 cm of new shoot growth) were sprayed until run-off with an aqueous preparation containing 25 ppm of active ingredient. After 22 days of cultivation under greenhouse conditions, total new shoot growth of the controls and the treated plants was 55 cm and 44 cm, respectively. In the apical part of this material the following GAs (roughly ordered in biosynthetic sequence) were detected at the following levels (control/treated in microgram per kilogram dry weight): GA19 (31/62), GA29 (24/36), GA20 (11/20), GA1 (4/3), and GA8 (8/3). These results clearly demonstrate that prohexadione-Ca blocks primarily the hydroxylation of GA20 into GA1. This leads to reduced levels of the highly active GA1 and of GA8, its inactive metabolite, whereas GA20 and the other inactive precursors accumulate. The data support older observations obtained in vitro, which indicate that GA20 3β-hydroxylase and related dioxygenases are the primary targets of prohexadione-Ca and similar compounds.
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Dünisch, Oliver, Matthias Fladung, Satoshi Nakaba, Yoko Watanabe, and Ryo Funada. "Influence of overexpression of a gibberellin 20-oxidase gene on the kinetics of xylem cell development in hybrid poplar (Populus tremula L. and P. tremuloides Michx.)." Holzforschung 60, no. 6 (November 1, 2006): 608–17. http://dx.doi.org/10.1515/hf.2006.103.
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Abstract Gibberellins (GAs) are important regulators of shoot growth in trees. We studied the kinetics of xylem formation in hybrid poplar (Populus tremula L.×P. tremuloides Michx.) in which the key regulatory gene gibberellin acid 20 oxidase (GA20-oxidase) isolated from Arabidopsis is overexpressed. Increments in the height and radius of shoots were registered by high-resolution laser measurements. The anatomical and chemical structure of mature xylem cells was studied by light electron microscopy and UV spectrophotometry. Transgenic plants showed an increase in height growth, but a lower speed of cell elongation during primary growth compared to wild-type plants. During the first year of growth, transgenic plants showed a higher radius increment, an increase in the period of cell expansion of vessels and fibres and their final size, and a higher lignin content of the compound middle lamella between fibres compared to wild-type plants. In contrast, during the third year of growth, only a slight increase in the period of cell expansion of fibre cells was observed in transgenic compared to wild-type plants. Analyses of GA20-oxidase expression in leaves and shoots of 6-month- and 3-year-old plants of three different independent transgenic lines revealed a decrease in its expression only in shoots but not in leaves of the 3-year-old plants. The results indicate that overexpression of the GA20-oxidase gene in young shoots of transgenic poplar predominately affects cell expansion, while no GA20-oxidase expression was observed in shoots of 3-year-old transgenic plants, resulting in wild-type xylem cell development.