Journal articles: 'Lactucine'

1

Zidorn, Christian, Ernst-Peter Ellmerer, Werner Heller, Richard Greil, Manuela Guggenberger, Karl-Hans Ongania, and Hermann Stuppner. "A New Sesquiterpene Lactone Sulfate from Reichardia gaditana (Asteraceae)." Zeitschrift für Naturforschung B 62, no. 1 (January 1, 2007): 132–34. http://dx.doi.org/10.1515/znb-2007-0121.

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The new sesquiterpenoid 8-deoxy-15-(3′-hydroxy-2′-methyl-propanoyl)-lactucin 3′-sulfate (1) was isolated from the methanolic extract of roots of Reichardia gaditana L. The compound was isolated by silica gel column chromatography (CC) and repeated Sephadex LH-20 CC. Structure elucidation was accomplished by high-resolution mass spectrometry and by 1D- and 2D-NMR spectroscopy. The chemosystematic significance of the new compound is discussed in the context of sesquiterpenoids from other members of the Lactuceae tribe of the Asteraceae family.

2

Wang, Xin, Min Liu, Guo He Cai, Yan Chen, Xiao Chen Shi, Cong Cong Zhang, Bo Xia, et al. "A Potential Nutraceutical Candidate Lactucin Inhibits Adipogenesis through Downregulation of JAK2/STAT3 Signaling Pathway-Mediated Mitotic Clonal Expansion." Cells 9, no. 2 (January 31, 2020): 331. http://dx.doi.org/10.3390/cells9020331.

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The prevalence of obesity has increased dramatically worldwide in the past ~50 years. Searching for safe and effective anti-obesity strategies are urgently needed. Lactucin, a plant-derived natural small molecule, is known for anti-malaria and anti-hyperalgesia. The study is to investigate whether lactucin plays a key role in adipogenesis. To this end, in vivo male C57BL/6 mice fed a high-fat diet (HFD) were treated with 20 mg/kg/day of lactucin or vehicle by gavage for seven weeks. Compared with vehicle-treated controls, Lactucin-treated mice showed lower body mass and mass of adipose tissue. Consistently, in vitro 3T3-L1 cells were treated with 20 μM of lactucin. Compared to controls, lactucin-treated cells showed significantly less lipid accumulation during adipocyte differentiation and lower levels of lipid synthesis markers. Mechanistically, we showed the anti-adipogenic property of lactucin was largely limited to the early stage of adipogenesis. Lactucin-treated cells fail to undergo mitotic clonal expansion (MCE). Further studies demonstrate that lactucin-induced MCE arrests might result from reduced phosphorylation of JAK2 and STAT3. We then asked whether activation of JAK2/STAT3 would restore the inhibitory effect of lactucin on adipogenesis with pharmacological STAT3 activator colivelin. Our results revealed similar levels of lipid accumulation between lactucin-treated cells and controls in the presence of colivelin, indicating that inactivation of STAT3 is the limiting factor for the anti-adipogenesis of lactucin in these cells. Together, our results provide the indication that lactucin exerts an anti-adipogenesis effect, which may open new therapeutic options for obesity.

3

Imam, Khandaker Md Sharif Uddin, Yu Tian, Fengjiao Xin, Yingying Xie, and Boting Wen. "Lactucin, A Bitter Sesquiterpene from Cichorium intybus, Inhibits Cancer Cell Proliferation by Downregulating the MAPK and Central Carbon Metabolism Pathway." Molecules 27, no. 21 (October 29, 2022): 7358. http://dx.doi.org/10.3390/molecules27217358.

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Lung cancer, especially adenocarcinoma, is the second most occurring and highest fatality-causing cancer worldwide. Many natural anticancer compounds, such as sesquiterpene lactones (SLs), show promising anticancer properties. Herein, we examined Lactucin, an SL from the plant Cichorium intybus, for its cytotoxicity, apoptotic-inducing, cell cycle inhibiting capacity, and associated protein expression. We also constructed a biotinylated Lactucin probe to isolate interacting proteins and identified them. We found that Lactucin stops the proliferation of A549 and H2347 lung adenocarcinoma cell lines while not affecting normal lung cell MRC5. It also significantly inhibits the cell cycle at G0/G1 stage and induces apoptosis. The western blot analysis shows that Lactucin downregulates the MAPK pathway, cyclin, and cyclin-dependent kinases, inhibiting DNA repair while upregulating p53, p21, Bax, PTEN, and downregulation of Bcl-2. An increased p53 in response to DNA damage upregulates p21, Bax, and PTEN. In an activity-based protein profiling (ABPP) analysis of A549 cell’s protein lysate using a biotinylated Lactucin probe, we found that Lactucin binds PGM, PKM, and LDHA PDH, four critical enzymes in central carbon metabolism in cancer cells, limiting cancer cells in its growth; thus, Lactucin inhibits cancer cell proliferation by downregulating the MAPK and the Central Carbon Metabolism pathway.

4

Zheleva-Dimitrova, Dimitrina, Alexandra Petrova, Gokhan Zengin, Kouadio Ibrahime Sinan, Vessela Balabanova, Olivier Joubert, Christian Zidorn, Yulian Voynikov, Rumyana Simeonova, and Reneta Gevrenova. "Metabolite profiling and bioactivity of Cicerbita alpina (L.) Wallr. (Asteraceae, Cichorieae)." Plants 12, no. 5 (February 23, 2023): 1009. http://dx.doi.org/10.3390/plants12051009.

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Cicerbita alpina (L.) Wallr. is a perennial herbaceous plant in the tribe Cichorieae (Lactuceae), Asteraceae family, distributed in the mountainous regions in Europe. In this study, we focused on the metabolite profiling and the bioactivity of C. alpina leaves and flowering heads methanol-aqueous extracts. The antioxidant activity of extracts, as well as inhibitory potential towards selected enzymes, involving in several human diseases, including metabolic syndrome (α-glucosidase, α-amylase, and lipase), Alzheimer’s disease, (cholinesterases: AChE, BchE), hyperpigmentation (tyrosinase), and cytotoxicity were assessed. The workflow comprised ultra-high-performance liquid chromatography—high-resolution mass spectrometry (UHPLC-HRMS). UHPLC-HRMS analysis revealed more than 100 secondary metabolites, including acylquinic, acyltartaric acids, flavonoids, bitter sesquiterpene lactones (STLs), such as lactucin, dihydrolactucin, their derivatives, and coumarins. Leaves showed a stronger antioxidant activity compared to flowering heads, as well as lipase (4.75 ± 0.21 mg OE/g), AchE (1.98 ± 0.02 mg GALAE/g), BchE (0.74 ± 0.06 mg GALAE/g), and tyrosinase (49.87 ± 3.19 mg KAE/g) inhibitory potential. Flowering heads showed the highest activity against α-glucosidase (1.05 ± 0.17 mmol ACAE/g) and α-amylase (0.47 ± 0.03). The obtained results highlighted C. alpina as a rich source of acylquinic, acyltartaric acids, flavonoids, and STLs with significant bioactivity, and therefore the taxon could be considered as a potential candidate for the development of health-promoting applications.

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Zhang, Fu-Hua, Yu-Ling Yan, Ying Wang, and Zhen Liu. "Lactucin induces potent anti-cancer effects in HL-60 human leukemia cancer cells by inducing apoptosis and sub-G1 cell cycle arrest." Bangladesh Journal of Pharmacology 11, no. 2 (April 15, 2016): 478. http://dx.doi.org/10.3329/bjp.v11i2.26729.

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The main purpose of the present study was to examine the antitumor and apoptotic effects of lactucin in HL-60 human leukemia cancer cells. MTT assay was used to examine the cytotoxic effects of lactucin while as phase contrast, fluorescence and transmission electron microscopy techniques were used to evaluate the apoptotic effects of lactucin in these cells. Flow cytometry was used to assess the effects of lactucin on cell cycle phase distribution. The results indicate that lactucin induced potent, time– and dose-dependent antitumor effects. The microscopic techniques showed that lactucin induced characteristic features of apoptosis including cell shrinkage, membrane blebbing, appearance of vacuoles, swelling of mitochondria and endoplasmic reticulum. Viable cells are stained green, early apoptotic cells are stained yellow, while as late apoptotic cells are stained reddish orange. Flow cytometry revealed that lactucin induced sub-G1 cell cycle arrest.Video ClipsPhase contrast microscopy: <a href="https://www.youtube.com/v/xrTjOVvlTxQ">1</a> <a href="https://www.youtube.com/v/GxuMkGnkpSE">2</a> <a href="https://www.youtube.com/v/SfmdL2-O45Y">3</a> <a href="https://www.youtube.com/v/7vbJ9HMRTHU">4</a> <a href="https://www.youtube.com/v/u4aLzmlXF8s">5</a> <a href="https://www.youtube.com/v/ucl8DjPeV9c">6</a> <a href="https://www.youtube.com/v/uI932TJVfFY">7</a> <a href="https://www.youtube.com/v/5sMlUKbKMhc">8</a> <a href="https://www.youtube.com/v/-tx20gFHYnc">9</a>

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Kisiel, Wanda, and Klaudia Michalska. "Root Constituents of Cichorium pumilum and Rearrangements of Some Lactucin-like Guaianolides." Zeitschrift für Naturforschung C 58, no. 11-12 (December 1, 2003): 789–92. http://dx.doi.org/10.1515/znc-2003-11-1206.

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Abstract Two eudesmanolides, eight lactucin-like guaianolides and five phenolic compounds were isolated for the first time from roots of Cichorium pumilum, along with two previously reported eudesmane-type sesquiterpene lactones. Rearrangements of some lactucin-like guaianolides during isolation procedures were also discussed.

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van Herwijnen, Z. O., and J. C. Manning. "A review of the history and taxonomy of the enigmatic southern African endemic wild lettuce Lactuca dregeana DC. (Asteraceae: Lactuceae: Lactucinae)." South African Journal of Botany 108 (January 2017): 352–58. http://dx.doi.org/10.1016/j.sajb.2016.08.016.

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8

Peters, Angeline M., and Aart van Amerongen. "Relationship between Levels of Sesquiterpene Lactones in Chicory and Sensory Evaluation." Journal of the American Society for Horticultural Science 123, no. 2 (March 1998): 326–29. http://dx.doi.org/10.21273/jashs.123.2.326.

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In this pilot study, we investigated the relationship between levels of bitter sesquiterpene lactones and sensory evaluation of chicory (Cichorium intybus L.). The levels of two bitter sesquiterpene lactones—lactucopicrin and lactucin-like sesquiterpene lactones—were measured by ELISA in raw and cooked chicory samples from several cultivars. Data were compared with the results of a sensory evaluation on the flavor attributes bitterness, typical chicory flavor, and total flavor intensity of identical chicory samples. Linear regression analysis demonstrated that the levels of lactucin-like sesquiterpene lactones were significantly related to bitterness (P = 0.006) and total flavor intensity (P = 0.03) attributes in raw chicory samples. When cooked chicory samples were evaluated, the levels of lactucin-like sesquiterpene lactones were significantly related to bitterness (P = 0.002), typical chicory flavor (P < 0.001), and total flavor intensity (P = 0.009) attributes, while lactucopicrin levels were related to bitterness (P = 0.002) only. These results show that the ELISA can be useful to predict flavor attributes in chicory.

9

Mbofung, Gladys Y., Soon Gyu Hong, and Barry M. Pryor. "Phylogeny of Fusarium oxysporum f. sp. lactucae Inferred from Mitochondrial Small Subunit, Elongation Factor 1-α, and Nuclear Ribosomal Intergenic Spacer Sequence Data." Phytopathology® 97, no. 1 (January 2007): 87–98. http://dx.doi.org/10.1094/phyto-97-0087.

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Fusarium oxysporum f. sp. lactucae, causal agent of Fusarium wilt of lettuce, is a serious pathogen recently reported in Arizona. Sequence analysis of the mitochondrial small subunit (mtSSU), translation elongation factor 1-α (EF-1α) gene, and the nuclear ribosomal DNA intergenic spacer (IGS) region was conducted to resolve relationships among f. sp. lactucae isolates, F. oxysporum isolates from other hosts, and local non-pathogenic isolates. Analysis of mtSSU sequences provided limited phylogenetic resolution and did not differentiate the lactucae isolates from 13 other F. oxysporum isolates. Analysis of EF-1α sequences resulted in moderate resolution, grouping seven formae speciales with the lactucae isolates. Analysis of the IGS region revealed numerous sequence polymorphisms among F. oxysporum formae speciales consisting of insertions, deletions, and single nucleotide transitions and substitutions. Repeat sequence analysis revealed several duplicated subrepeat units that were distributed across much of the region. Based on analysis of the IGS sequence data, lactucae race 1 isolates resolved as a monophyletic group with three other formae speciales of F. oxysporum. In all analyses, lactucae race 2 isolates composed a separate lineage that was phylo-genetically distinct and distantly related to the lactucae race 1 isolates.

10

Wesołowska, A., A. Nikiforuk, K. Michalska, W. Kisiel, and E. Chojnacka-Wójcik. "Analgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice." Journal of Ethnopharmacology 107, no. 2 (September 2006): 254–58. http://dx.doi.org/10.1016/j.jep.2006.03.003.

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11

Castoldi, Renata, Hamilton César de O. Charlo, Tagli Dalpian, Danilo M. Melo, Adelita P. Botelho, and Leila T. Braz. "Identification of new Bremia lactucae races in lettuce in São Paulo state." Horticultura Brasileira 30, no. 2 (June 2012): 209–13. http://dx.doi.org/10.1590/s0102-05362012000200005.

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Lettuce is the most consumed leafy vegetable in Brazil. However, its production has faced increasing difficulties mainly due to the infestation of producing areas with Bremia lactucae, the causing agent of downy mildew, the worst disease in lettuce. The aim of this study was to identify B. lactucae races occurring in lettuce producing areas of São Paulo state, during 2008 and 2009. Lettuce leaf samples containing B. lactucae sporangia were collected in the major lettuce producing areas of São Paulo. Each sample was considered an isolate. After the multiplication of sporangia in the susceptible cultivar Solaris, with subsequent inoculation in the differentiating cultivars, the evaluations were performed on the same day of the first sporulation in the susceptible cultivar 'Cobham Green (DM 0)'. In 2008 one new B. lactucae code was identified. SPBl:05 was the denomination proposed to it. In 2009 one another B. lactucae code was identified, that is, 63/63/02/00, whose denomination was proposed to be SPBl:06.

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Farrara, Barry F., and Richard W. Michelmore. "Identification of New Sources of Resistance to Downy Mildew in Lactuca Spp." HortScience 22, no. 4 (August 1987): 647–49. http://dx.doi.org/10.21273/hortsci.22.4.647.

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Abstract More than 300 accessions of Lactuca spp. recently collected in the Mediterranean region and California were screened for resistance to downy mildew (Bremia lactucae Regel). Accessions were evaluated in the seedling stage with two isolates of B. lactucae, which together have virulence to all known resistance factors. Four accessions demonstrated complete resistance to both isolates, indicating that new resistance was present. This resistance was confirmed using further isolates of B. lactucae. None of these lines, however, was resistant to all the isolates used.

13

Luo, Yuqin, Weijun Yang, Abudujilili Abuduaini, and Haji Akber Aisa. "Preparation of Magnetic Nanoliposomes of Sesquiterpene-Rich Fraction from Cichorium glandulosum and Its Tissue Distribution in Mice." Evidence-Based Complementary and Alternative Medicine 2018 (October 18, 2018): 1–6. http://dx.doi.org/10.1155/2018/8549519.

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Objective. To prepare and study the distribution of magnetic nanoliposomes of Sesquiterpene-Rich Fraction from Cichorium glandulosum (SRF-MLN) (under magnetic field) in the main organs of mice. Methods. The SRF-MLN was prepared by ethanol injection-sonication precipitation method. The quality of its pharmaceutical properties was investigated by the active ingredient lactucin. The drug concentration and distribution of lactucin in different tissues and organs including whole blood, liver, heart, spleen, lung, and kidney were evaluated with Sesquiterpene-Rich Fraction from Cichorium glandulosum (SRF-LP) as a control. Results. The prepared SRF-MLN was spherical and monodispersed with an average particle diameter of 65 ± 1 nm, encapsulation efficiency of 91.3% ± 1.5% (RSD% = 1.5), and drug loading rate of 4.7% ± 0.3% (RSD% = 0.7). Dispersion coefficient PDI was 0.157 and Zeta potential was −17.5 mV. The lactucin concentration of SRF-MLN after 10 min of intravenous injection in heart, liver, spleen, lung, and kidney was significantly higher than that of SRF-LP group. The AUC0-12h values of liver tissue were obviously higher than other tissues and MRT was significantly prolonged under the action of the magnetic field (p<0.01). Conclusion. The prepared SRF-MLN can change the distribution of drugs in different tissues and organs, prolonging the action time of the drugs in the body, and it has certain specificity under the action of applied magnetic field.

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Ko, Heejin, Yu Jin Shon, Wonchul Lim, Tae-Gyu Nam, Wook Chul Kim, Nam Hee Kim, and Tae-Gyu Lim. "The Antimelanogenic Activity of the Extract of Heukharang Lettuce (Lactuca sativa L.) Leaf." Journal of Food Biochemistry 2024 (February 2, 2024): 1–12. http://dx.doi.org/10.1155/2024/6668222.

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Heukharang (Lactuca sativa L.), the artificially developed lettuce cultivar for enhancement of lactucin content, exhibits antioxidant activities and sleep-promoting effects. However, potential of Heukharang as a raw material for the skin-whitening agent has not been investigated yet. This study evaluated the effects of Heukharang extract (HHE) on α-melanocyte-stimulating hormone (α-MSH)-induced melanogenesis in vitro and in vivo models. Our findings revealed that HHE (25–100 μg/mL) effectively inhibited α-MSH-induced melanin synthesis in both 2D and 3D cell culture environments without compromising the viability of the B16F10 murine melanoma cell line. Furthermore, HHE suppressed intracellular tyrosinase activity, along with both gene and protein expression of tyrosinase (TYR) and tyrosinase-related protein (TRP)-1 and TRP-2. HHE downregulated the mRNA level of microphthalmia-associated transcription factor (MITF) and the phosphorylation of cAMP response element-binding (CREB) protein. The antimelanogenic activity of HHE (50 and 100 μg/mL) was also confirmed using a zebrafish embryo model, highlighting its efficacy in inhibiting α-MSH-induced melanogenesis through the downregulating CREB/MITF/TYR signaling pathways. Moreover, our study demonstrated that a corresponding amount of lactucin (5–20 μM) to the HHE inhibited and regulated melanogenesis. These results collectively suggest that HHE, enriched with lactucin, holds promise as a potential skin-whitening agent for nutricosmetic industries.

15

Fatemi, Samira, Danny Haelewaters, Hector Urbina, Samuel Brown, Makenna L. Houston, and M. Catherine Aime. "Sporobolomyces lactucae sp. nov. (Pucciniomycotina, Microbotryomycetes, Sporidiobolales): An Abundant Component of Romaine Lettuce Phylloplanes." Journal of Fungi 8, no. 3 (March 16, 2022): 302. http://dx.doi.org/10.3390/jof8030302.

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Shifts in food microbiomes may impact the establishment of human pathogens, such as virulent lineages of Escherichia coli, and thus are important to investigate. Foods that are often consumed raw, such as lettuce, are particularly susceptible to such outbreaks. We have previously found that an undescribed Sporobolomyces yeast is an abundant component of the mycobiome of commercial romaine lettuce (Lactuca sativa). Here, we formally describe this species as Sporobolomyces lactucae sp. nov. (Pucciniomycotina, Microbotryomycetes, and Sporidiobolales). We isolated multiple strains of this yeast from commercial romaine lettuce purchased from supermarkets in Illinois and Indiana; additional isolates were obtained from various plant phylloplanes in California. S. lactucae is a red-pigmented species that is similar in appearance to other members of the genus Sporobolomyces. However, it can be differentiated by its ability to assimilate glucuronate and D-glucosamine. Gene genealogical concordance supports S. lactucae as a new species. The phylogenetic reconstruction of a four-locus dataset, comprising the internal transcribed spacer and large ribosomal subunit D1/D2 domain of the ribosomal RNA gene, translation elongation factor 1-α, and cytochrome B, places S. lactucae as a sister to the S. roseus clade. Sporobolomyces lactucae is one of the most common fungi in the lettuce microbiome.

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Galatti, Francine de Souza, Renata Castoldi, Leila Trevisan Braz, and Rita de Cássia Panizzi. "Monitoramento de raças de Bremia lactucae em 2010 e 2011 no Estado de São Paulo." Summa Phytopathologica 38, no. 4 (December 2012): 271–79. http://dx.doi.org/10.1590/s0100-54052012000400001.

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A alface é uma das mais importantes hortaliças folhosas cultivadas no Brasil. Porém, com a intensificação da produção, a dificuldade em se cultivar essa hortaliça tem aumentado principalmente pela infestação das áreas de produção pelo fitopatógeno Bremia lactucae Regel, agente causador do míldio, uma das principais doenças da alface. O objetivo deste trabalho foi identificar raças de Bremia lactucae nos anos de 2010 e 2011 nos principais municípios produtores de alface do Estado de São Paulo. Para isso, coletaram-se folhas com esporângios de B. lactucae em municípios produtores de alface, sendo que cada amostra foi considerada um isolado, totalizando 56 e 96 nos anos de 2010 e 2011, respectivamente. Os esporângios coletados foram multiplicados na cultivar suscetível Solaris, com posterior inoculação nas cultivares diferenciadoras, realizando-se as avaliações no mesmo dia do aparecimento da primeira esporulação na cultivar suscetível 'Green Tower' (DM 0). No ano de 2010, identificou-se um novo código de B. lactucae em alface (63/31/03/00), correspondente a uma nova raça na qual se propôs a denominação de SPBl:07. No ano de 2011, outros dois códigos de B. lactucae foram identificados (31/63/51/00 e 31/63/9/00), aos quais se propôs as denominações de SPBl:08 e SPBl:09, respectivamente.

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Kunjeti, Sridhara G., Amy Anchieta, Frank N. Martin, Young-Joon Choi, Marco Thines, Richard W. Michelmore, Steven T. Koike, et al. "Detection and Quantification of Bremia lactucae by Spore Trapping and Quantitative PCR." Phytopathology® 106, no. 11 (November 2016): 1426–37. http://dx.doi.org/10.1094/phyto-03-16-0143-r.

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Bremia lactucae is an obligate, oomycete pathogen of lettuce that causes leaf chlorosis and necrosis and adversely affects marketability. The disease has been managed with a combination of host resistance and fungicide applications with success over the years. Fungicide applications are routinely made under the assumption that inoculum is always present during favorable environmental conditions. This approach often leads to fungicide resistance in B. lactucae populations. Detection and quantification of airborne B. lactucae near lettuce crops provides an estimation of the inoculum load, enabling more judicious timing of fungicide applications. We developed a quantitative polymerase chain reaction (qPCR)-based assay using a target sequence in mitochondrial DNA for specific detection of B. lactucae. Validation using amplicon sequencing of DNA from 83 geographically diverse isolates, representing 14 Bremia spp., confirmed that the primers developed for the TaqMan assays are species specific and only amplify templates from B. lactucae. DNA from a single sporangium could be detected at a quantification cycle (Cq) value of 32, and Cq values >35 were considered to be nonspecific. The coefficient of determination (R2) for regression between sporangial density derived from flow cytometry and Cq values derived from the qPCR was 0.86. The assay was deployed using spore traps in the Salinas Valley, where nearly half of U.S. lettuce is produced. The deployment of this sensitive B. lactucae-specific assay resulted in the detection of the pathogen during the 2-week lettuce-free period as well as during the cropping season. These results demonstrate that this assay will be useful for quantifying inoculum load in and around the lettuce fields for the purpose of timing fungicide applications based on inoculum load.

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Paugh, Kelley R., and Thomas R. Gordon. "The Population of Fusarium oxysporum f. sp. lactucae in California and Arizona." Plant Disease 104, no. 6 (June 2020): 1811–16. http://dx.doi.org/10.1094/pdis-06-19-1228-re.

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Fusarium wilt of lettuce, caused by Fusarium oxysporum f. sp. lactucae, is now found in all major lettuce producing regions in California and Arizona. The population structure of F. oxysporum f. sp. lactucae in California and Arizona was characterized based on somatic compatibility and sequences of the translation elongation factor 1-α gene (EF-1α) and rDNA intergenic spacer region (IGS). In this study, 170 isolates were tested for somatic compatibility based on heterokaryon formation, using complementary nitrate nonutilizing (nit) mutants. Five subgroups (A to E) of somatic compatibility group 0300 were identified. Isolates associated with the same subgroup had a strong complementation reaction, whereas reactions between isolates of different subgroups were weak or delayed. An isolate from the first known infestation of Fusarium wilt of lettuce in California was associated with subgroup A, which predominated among isolates in our collection. Isolates representative of each subgroup were confirmed to be associated with race 1, based on the reaction of differential lettuce cultivars. It is possible that somatic compatibility subgroups B to E of F. oxysporum f. sp. lactucae were derived from subgroup A, as a consequence of somatic mutations affecting compatibility. If so, subgroups of F. oxysporum f. sp. lactucae may represent an intermediate step in divergence that will lead to clearly separable compatibility groups. Sequences of EF-1α and IGS were both identical for 58 isolates of F. oxysporum f. sp. lactucae that represented all somatic compatibility subgroups and locations from which isolates were obtained, indicating that subgroups were derived from the same clonal lineage (VCG 0300).

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Dhar, Nikhilesh, Bullo Erena Mamo, Krishna V. Subbarao, Steven T. Koike, Alan Fox, Amy Anchieta, and Steven J. Klosterman. "Measurements of Aerial Spore Load by qPCR Facilitates Lettuce Downy Mildew Risk Advisement." Plant Disease 104, no. 1 (January 2020): 82–93. http://dx.doi.org/10.1094/pdis-03-19-0441-re.

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The lettuce downy mildew pathogen, Bremia lactucae, is an obligate oomycete that causes extensive produce losses. Initial chlorotic symptoms that severely reduce the market value of the produce are followed by the appearance of white, downy sporulation on the abaxial side of the leaves. These spores become airborne and disseminate the pathogen. Controlling lettuce downy mildew has relied on repeated fungicide applications to prevent outbreaks. However, in addition to direct economic costs, heterogeneity and rapid adaptation of this pathogen to repeatedly applied fungicides has led to the development of fungicide-insensitivity in the pathogen. We deployed a quantitative PCR assay-based detection method using a species-specific DNA target for B. lactucae coupled with a spore trap system to measure airborne B. lactucae spore loads within three commercial fields that each contained experimental plots, designated EXP1 to EXP3. Based upon these measurements, when the spore load in the air reached a critical level (8.548 sporangia per m3 air), we advised whether or not to apply fungicides on a weekly basis within EXP1 to EXP3. This approach saved three sprays in EXP1, and one spray each in EXP2 and EXP3 without a significant increase in disease incidence. The reduction in fungicide applications to manage downy mildew can decrease lettuce production costs while slowing the development of fungicide resistance in B. lactucae by eliminating unnecessary fungicide applications.

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Hulbert, S. H., T. W. Ilott, E. J. Legg, S. E. Lincoln, E. S. Lander, and R. W. Michelmore. "Genetic analysis of the fungus, Bremia lactucae, using restriction fragment length polymorphisms." Genetics 120, no. 4 (December 1, 1988): 947–58. http://dx.doi.org/10.1093/genetics/120.4.947.

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Abstract Restriction fragment length polymorphisms (RFLPs) were developed as genetic markers for Bremia lactucae, the biotrophic Oomycete fungus which causes lettuce downy mildew. By using 55 genomic and cDNA probes, a total of 61 RFLP loci were identified among three heterothallic isolates of B. lactucae. Of these 61 RFLP loci, 53 were heterozygous in at least one of the three strains and thus were informative for linkage analysis in at least one of two F1 crosses that were performed. Analysis of the cosegregation of these 53 RFLPs, eight avirulence loci and the mating type locus allowed the construction of a preliminary genetic linkage map consisting of 13 small linkage groups. Based on the extent of linkage detected among probes, the genome of B. lactucae can be estimated to be approximately 2000 cM. Linkage was detected between a RFLP locus and an avirulence gene, providing a potential starting point for chromosome walking to clone an avirulence gene. The high frequency of DNA polymorphism in naturally occurring isolates and the proper Mendelian segregation of loci detected by low copy number probes indicates that it will be possible to construct a detailed genetic map of B. lactucae using RFLPs as markers. The method of analysis employed here should be applicable to many other outbreeding, heterozygous species for which defined inbred lines are not available.

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Pasquali, Matias, Flavia Dematheis, Maria Lodovica Gullino, and Angelo Garibaldi. "Identification of Race 1 of Fusarium oxysporum f. sp. lactucae on Lettuce by Inter-Retrotransposon Sequence-Characterized Amplified Region Technique." Phytopathology® 97, no. 8 (August 2007): 987–96. http://dx.doi.org/10.1094/phyto-97-8-0987.

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Fusarium wilt of lettuce, caused worldwide by Fusarium oxysporum f. sp. lactucae, is an emerging seed-transmitted disease on Lactuca sativa. In order to develop a molecular diagnostic tool for identifying race 1 (VCG0300) of the pathogen on vegetable samples, an effective technique is presented. Inter-retrotransposon amplified polymorphism polymerase chain reaction (PCR), a technique based on the amplification of genomic regions between long terminal repeats, was applied. It was shown to be useful for grouping F. oxysporum f. sp. lactucae race 1 isolates. Inter-retrotransposon sequence-characterized amplified regions (IR-SCAR) was used to develop a specific set of PCR primers to be utilized for differentiating F. oxysporum f. sp. lactucae isolates from other F. oxysporum isolates. The specific primers were able to uniquely amplify fungal genomic DNA from race 1 isolates obtained in Italy, Portugal, the United States, Japan, and Taiwan. The primers also were specific to pathogen DNA obtained from artificially infected lettuce seed and naturally and artificially infected plants.

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Whitton, Jeannette, Robert S. Wallace, and Robert K. Jansen. "Phylogenetic relationships and patterns of character change in the tribe Lactuceae (Asteraceae) based on chloroplast DNA restriction site variation." Canadian Journal of Botany 73, no. 7 (July 1, 1995): 1058–73. http://dx.doi.org/10.1139/b95-115.

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The Lactuceae is perhaps the most easily recognizable tribe in the Asteraceae, distinguished by the presence of milky latex and of ligulate florets in the inflorescence. Three existing taxonomic treatments of the tribe establish subtribal classifications but fail to resolve relationships among major lineages. Our study of chloroplast DNA restriction site variation sampled 60 Lactuceae taxa. We detected 1268 mutations, 612 of which are phylogenetically informative. Despite the large amount of variation detected, little resolution of relationships among major lineages was obtained from parsimony analyses, although the monophyly of many groups is strongly supported. These results, when considered along with data from morphological analyses of other workers, suggest that rapid diversification played an important role in early stages of the tribe's evolution. Our examination of character change further reveals that as noted by other workers, restriction site variation is not evenly distributed across the chloroplast genome and that regions with higher levels of variation do not necessarily have higher amounts of homoplasy. This is somewhat surprising, since we found that amounts of homoplasy along terminal branches of our phylogenetic tree are related to levels of divergence. Key words: Asteraceae, chloroplast DNA, homoplasy, Lactuceae, phylogeny, restriction site variation.

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Zhang, Ningwen W., Koen Pelgrom, Rients E. Niks, Richard G. F. Visser, and Marieke J. W. Jeuken. "Three Combined Quantitative Trait Loci from Nonhost Lactuca saligna Are Sufficient to Provide Complete Resistance of Lettuce Against Bremia lactucae." Molecular Plant-Microbe Interactions® 22, no. 9 (September 2009): 1160–68. http://dx.doi.org/10.1094/mpmi-22-9-1160.

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The nonhost resistance of wild lettuce (Lactuca saligna) to downy mildew (Bremia lactucae) is based on at least 15 quantitative trait loci (QTL), each effective at one or more plant developmental stages. We used QTL pyramiding (stacking) to determine how many of these QTL from L. saligna are sufficient to impart complete resistance towards B. lactucae to cultivated lettuce, L. sativa. The alleles of four of the most promising QTL, rbq4, rbq5, rbq6+11, and rbq7 are effective at both the young and adult plant stages. Lines with these four QTL in all possible combinations were generated by crossing the respective backcross inbred lines (BIL). Using the 11 resulting lines (combiBIL), we determined that combinations of three QTL, rbq4, rbq5, and rbq6+11, led to increased levels of resistance; however, one QTL, rbq7, did not add to the resistance level when combined with the other QTL. One line, tripleBIL268, which contains the three QTL rbq4, rbq5, and rbq6+11, was completely resistant to B. lactucae at the young plant stage. This suggests that these three QTL are sufficient to confer the complete resistance of the nonhost L. saligna and any additional QTL in L. saligna are redundant. Histological analysis of B. lactucae infection in L. saligna, the BIL, and the combiBIL 48 h after inoculation revealed different microscopical phenotypes of resistance. The QTL differed with respect to the stage of the infection process with which they interfered.

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Fall, M. L., H. Van der Heyden, C. Beaulieu, and O. Carisse. "Bremia lactucae Infection Efficiency in Lettuce is Modulated by Temperature and Leaf Wetness Duration Under Quebec Field Conditions." Plant Disease 99, no. 7 (July 2015): 1010–19. http://dx.doi.org/10.1094/pdis-05-14-0548-re.

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More than 80% of Canadian lettuce production is located in the province of Quebec. Yet most of our knowledge on the epidemiology of lettuce downy mildew (Bremia lactucae) is derived from controlled-condition experiments or field experiments conducted in subtropical climates and, thus, cannot readily be applied to Quebec lettuce production. The influence of temperature and leaf wetness duration on the infection efficiency (IE) of B. lactucae was studied for 4 years (2003, 2004, 2012, and 2013) under field and growth-chamber conditions. IE was defined as the ratio of the number of lesions/leaf to the airborne conidia concentration (ACC). B. lactucae ACC was measured with rotating-arm samplers three times/week. In addition, 72 lettuce trap plants/sampling day were exposed to the potential airborne B. lactucae inoculum and disease intensity was assessed after 7 days of incubation in greenhouse. Under growth-chamber conditions, an ACC of 1 conidium/m3 was sufficient to cause 1 lesion/leaf, and IE ranged from 0.25 to 1.00. Under field conditions, an ACC of 10 to 14 conidia/m3 was required to cause 1 lesion/leaf, and IE ranged from 0.02 to 0.10, except in 2004, when IE ranged from 0.03 to 1.00. IE increased with increasing leaf wetness duration but decreased with increasing temperature. Also, considering an observed average temperature range from 10 to 20°C in the area of Quebec, 2 h of leaf wetness was sufficient for infection by B. lactucae. Therefore, under Quebec lettuce production conditions, a leaf wetness period of 2 h and an ACC of 10 to 14 conidia/m3 can be used as risk indicators to facilitate disease management decisions. Also, under typical Quebec weather conditions, measuring both morning and evening leaf wetness events could be used to improve the reliability of leaf wetness duration as a downy mildew risk indicator. Further research is needed to validate these risk indicators for integration into management strategies.

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Ilgün, Selen, Esra Küpeli Akkol, Mert Ilhan, Derya Çiçek Polat, Ayse Baldemir Kılıç, Maksut Coşkun, and Eduardo Sobarzo-Sánchez. "Sedative Effects of Latexes Obtained from Some Lactuca L. Species Growing in Turkey." Molecules 25, no. 7 (March 30, 2020): 1587. http://dx.doi.org/10.3390/molecules25071587.

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Lactuca L. species belong to the Asteraceae family and these plants are traditionally used for therapeutic purposes around the world. The dried milky latex of L. serriola is known as “lettuce oil” and is used as a sedative in Turkey. This study aimed to evaluate the sedative effects and analyze the chemical compositions of latexes obtained from some Lactuca species growing in Turkey. The sedative effects were evaluated through various behavioral tests on mice. For this purpose, latexes were obtained from L. glareosa Boiss., L. viminea (L.) J. Presl and C. P, L. mulgedioides (Vis and Panćić) Boiss. and Kotschy ex. Boiss., L. saligna L., and L. serriola L. The latex from L. saligna showed the highest sedative effects, whilst L. serriola and L. viminea latexes also displayed significant sedative effects compared to the control group at a dose of 100 mg/kg. However, the latexes from L. glareosa and L. mulqedioides did not exhibit any sedative effects on mice. Characteristic sesquiterpene lactones (lactucin, lactucopicrin, 11,13β-dihydrolactucin, and 11,13β-dihydrolactucopicrin) were determined qualitatively and quantitatively by high-performance liquid chromatography (HPLC). Lactucin was identified as the main component.

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Douglas, George W. "Nomenclatural changes in the Asteraceae of British Columbia. II. Astereae, Eupatoreae, Inuleae, Lactuceae, and Heliantheae." Canadian Journal of Botany 64, no. 11 (November 1, 1986): 2726–27. http://dx.doi.org/10.1139/b86-360.

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Castoldi, Renata, Hamilton CO Charlo, Danilo M. Melo, Willame S. Candido, Pablo F. Vargas, Tagli Dalpian, and Leila T. Braz. "Obtaining resistant lettuce progenies to downy mildew." Horticultura Brasileira 32, no. 1 (2014): 69–73. http://dx.doi.org/10.1590/s0102-05362014000100011.

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Lettuce is the most consumed leafy vegetable in Brazil. Its production, nonetheless, is increasing in difficulties mainly due to the infestation of producing areas with Bremia lactucae. Thus, the use of horizontal resistant cultivars is the most viable alternative in controlling progress of disease. So, the objective of this study was to obtain resistant lettuce progenies to the races of downy mildew: SPBl:01, SPBl:02, SPBl:03, SPBl:04, SPBl:05, SPBl:06 and SPBl:07. The breeding consisted of two stages: crossover of parentals to obtain the resistant lettuce progenies and endurance test of the progeny to B. lactucae races. The parentals used to obtain progenies with resistance factor R-18 and R-38 were: JAB 4-13-7 and JAB 4-13-7. The Pedigree method was used for obtaining the progeny, using as default selections the Hortência cultivar and JAB 4-13-7genotype. After selection and selfing of the plants in the field, the resistance or susceptibility test was realized, by inoculation of the progenies from the crosses, with mixture of distilled water + sporangia of B. lactucae races SPBl:01, SPBl:02, SPBl:03, SPBl:04, SPBl:05, SPBl:06 and SPBl:07 obtained from isolates collected in the years 2008-2010. Fifteen days after inoculation, the seedlings were selected as resistant or susceptible, discarding those presenting sporulation and necrotic spots caused by B. lactucae. Through the Pedigree method we found 69 progenies F3 with good agronomic characteristics. However, after resistance or susceptibility test, only 19 showed all the plants resistant to downy mildew.

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Koike, S. T., and O. E. Ochoa. "Downy Mildew Caused by Bremia lactucae on Strawflower (Helichrysum bracteatum) in California." Plant Disease 91, no. 3 (March 2007): 326. http://dx.doi.org/10.1094/pdis-91-3-0326a.

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In 2006, field-planted strawflower (Helichrysum bracteatum (Venten.) Andr.) grown for cutflowers in coastal San Mateo County was severely infected with a downy mildew disease. Initial symptoms consisted of irregularly shaped chlorotic lesions. Lesions were typically vein delimited, and in particular, did not cross the central longitudinal vein of the lanceolate leaves. Lesions were large and could exceed 6 cm long. Profuse white sporulation developed on the abaxial sides of the lesions. As disease progressed, lesions became gray brown and necrotic. Cutflower stems having symptomatic foliage were unmarketable. Hyaline conidiophores emerged from stomata, branched dichotomously, and had branch tips ending in swollen vesicles bearing sterigmata. Conidia were hyaline and ovoid to globose in shape. The pathogen was identified as Bremia lactucae Regel. To establish pathogenicity, strawflower plants were spray inoculated with a conidial suspension of 1 × 104 conidia/ml, incubated for 24 h in a dew chamber (18 to 20°C), and then maintained in a greenhouse (22 to 24°C). After 14 days, symptoms and signs of downy mildew developed on inoculated plants and the pathogen was confirmed to be B. lactucae. Untreated control plants did not develop downy mildew. Because lettuce (Lactuca sativa L.) is grown extensively in this coastal region, we investigated the pathogenicity of B. lactucae from strawflower on lettuce by inoculating a lettuce downy mildew differential series that includes 20 lettuce lines, four wild L. serriola lines, and strawflower. A conidial suspension of 1 × 106 conidia/ml was applied to all plants; plants were then incubated in a growth chamber with irradiation at 15°C. After 14 days, only the strawflower plants showed downy mildew lesions and sporulation. Collected from diseased field-grown strawflower, 100 downy mildew conidia were measured and had dimensions of 24.4 × 17.4 μm. These conidia were significantly longer than the B. lactuca conidia collected from lettuce (21.8 × 18.1 μm) grown in a nearby area (LSD [P = 0.05] = 2.2), though dimensions were within the reported length range for B. lactucae (12 to 31 μm) (2). To our knowledge, this is the first report of downy mildew caused by B. lactucae on strawflower in California. Inoculation studies indicate that these strawflower and lettuce pathogens from California likely belong to distinct formae speciales (2), though a B. lactucae isolate in Italy was able to infect both hosts (1). The pathogen has been reported on strawflower in Florida, Egypt, Italy, and the United Kingdom (1). References: (1) A. Garibaldi et al. Plant Dis. 87:315, 2003. (2) W. M. Morgan. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 682. CAB International, Wallingford, UK, 1981.

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Promwee, Athakorn, and Warin Intana. "Trichoderma asperellum (NST-009): A potential native antagonistic fungus to control Cercospora leaf spot and promote the growth of ‘Green Oak’ lettuce (Lactuca sativa L.) cultivated in the commercial NFT hydroponic system." Plant Protection Science 58, No. 2 (March 28, 2022): 139–49. http://dx.doi.org/10.17221/69/2021-pps.

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Leaf spot caused by Cercospora lactucae-sativae is one of the most damaging diseases of ‘Green Oak’ lettuce in Thailand. This study was conducted to estimate the effectiveness of Trichoderma asperellum NST-009, a native strain in Thailand, to manage the leaf spot disease and enhance the growth of ‘Green Oak’ lettuce in a nutrient film technique (NFT) hydroponic system. In vitro tests showed that T. asperellum NST-009 significantly inhibited the mycelial growth of C. lactucae-sativae by 72.50%, and its antifungal metabolite from the culture filtrate of T. asperellum NST-009 inhibited the mycelial growth of C. lactucae-sativae by 93.26%. In the hydroponics experiment, T. asperellum NST-009 reduced the disease severity index by 67.51% compared to the inoculated control and significantly stimulated the growth of the ‘Green Oak’ lettuce in terms of the plant height (8.62%), canopy width (16.67%), leaf number (18.39%), shoot fresh weight (25.71%), root fresh weight (39.26%), and total P in the leaves (31.45%) compared to the control. In addition, T. asperellum NST-009 was found to survive in both the lettuce leaves and roots at 100.00%.

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Weng, Hui, Luanying He, Jiakun Zheng, Qing Li, Xiuping Liu, and Dongliang Wang. "Low Oral Bioavailability and Partial Gut Microbiotic and Phase II Metabolism of Brussels/Witloof Chicory Sesquiterpene Lactones in Healthy Humans." Nutrients 12, no. 12 (November 28, 2020): 3675. http://dx.doi.org/10.3390/nu12123675.

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Free and glycosylated sesquiterpene lactones (SLs), which are abundant in leafy vegetables including Brussels/witloof chicory, possess health-promoting effects in vivo. However, the pharmacokinetics of dietary source of SLs remain largely unknown. In this open-label and single-dose trial, sixteen healthy volunteers consumed 150 g of Brussels/witloof chicory juice containing 48.77 μmol SLs in 5 min. Blood, urine, and fecal samples were collected before and after chicory consumption in 24 h. No SLs were detected in the serum, urine, and fecal samples before chicory consumption in all of the participants. Chicory consumption increased lactucin, 11β,13-dihydrolactucin, and their glucuronide/sulfate conjugates, rather than lactucopicrin and 11β,13-dihydrolactucopicrin, as well as glycosylated SLs in biological samples. The peak concentration of total SLs in serum reached 284.46 nmol/L at 1 h, while, in urine, this peak was 220.3 nmol between 2 and 6 h. The recovery of total SLs in blood, urine, and feces was 7.03%, 1.13%, and 43.76% of the ingested dose, respectively. Human fecal suspensions with intestinal microbiota degraded glycosylated SLs in chicory, and converted lactucopicrin and 11β,13-dihydrolactucopicrin to lactucin and 11β,13-dihydrolactucin, respectively. Collectively, Brussels/witloof chicory SLs are poorly bioavailable and they undergo partial gut microbial and phase II metabolism in humans.

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Kim, Ki-Joong, and Billie L. Turner. "Systematic Overview of Krigia (Asteraceae-Lactuceae)." Brittonia 44, no. 2 (April 1992): 173. http://dx.doi.org/10.2307/2806832.

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32

Bremer, Kåre, and Kare Bremer. "New Subtribes of the Lactuceae (Asteraceae)." Novon 3, no. 4 (1993): 328. http://dx.doi.org/10.2307/3391378.

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33

Park, Jae Hong. "Karyomorphology of Youngia koidzumiana ( Compositae ; Lactuceae )." Korean Journal of Plant Taxonomy 21, no. 2 (June 30, 1991): 117–21. http://dx.doi.org/10.11110/kjpt.1991.21.2.117.

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Park, Jae Hong, and Kyung Choi. "Karyomorphology of Lapsana species ( Compositae - Lactuceae )." Korean Journal of Plant Taxonomy 24, no. 4 (December 30, 1994): 247–57. http://dx.doi.org/10.11110/kjpt.1994.24.4.247.

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35

Stassen, Joost H. M., Erik den Boer, Pim W. J. Vergeer, Annemiek Andel, Ursula Ellendorff, Koen Pelgrom, Mathieu Pel, et al. "Specific In Planta Recognition of Two GKLR Proteins of the Downy Mildew Bremia lactucae Revealed in a Large Effector Screen in Lettuce." Molecular Plant-Microbe Interactions® 26, no. 11 (November 2013): 1259–70. http://dx.doi.org/10.1094/mpmi-05-13-0142-r.

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Breeding lettuce (Lactuca sativa) for resistance to the downy mildew pathogen Bremia lactucae is mainly achieved by introgression of dominant downy mildew resistance (Dm) genes. New Bremia races quickly render Dm genes ineffective, possibly by mutation of recognized host-translocated effectors or by suppression of effector-triggered immunity. We have previously identified 34 potential RXLR(-like) effector proteins of B. lactucae that were here tested for specific recognition within a collection of 129 B. lactucae-resistant Lactuca lines. Two effectors triggered a hypersensitive response: BLG01 in 52 lines, predominantly L. saligna, and BLG03 in two L. sativa lines containing Dm2 resistance. The N-terminal sequences of BLG01 and BLG03, containing the signal peptide and GKLR variant of the RXLR translocation motif, are not required for in planta recognition but function in effector delivery. The locus responsible for BLG01 recognition maps to the bottom of lettuce chromosome 9, whereas recognition of BLG03 maps in the RGC2 cluster on chromosome 2. Lactuca lines that recognize the BLG effectors are not resistant to Bremia isolate Bl:24 that expresses both BLG genes, suggesting that Bl:24 can suppress the triggered immune responses. In contrast, lettuce segregants displaying Dm2-mediated resistance to Bremia isolate Bl:5 are responsive to BLG03, suggesting that BLG03 is a candidate Avr2 protein.

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Scott, J. C., T. R. Gordon, D. V. Shaw, and S. T. Koike. "Effect of Temperature on Severity of Fusarium Wilt of Lettuce Caused by Fusarium oxysporum f. sp. lactucae." Plant Disease 94, no. 1 (January 2010): 13–17. http://dx.doi.org/10.1094/pdis-94-1-0013.

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The effect of temperature on Fusarium wilt of lettuce (Lactuca sativa), caused by Fusarium oxysporum f. sp. lactucae, was examined in a controlled environment. Nine lettuce cultivars planted in infested potting mix (500 or 5,000 CFU/g) were maintained under high/low diurnal temperature regimes of 26/18°C, 28/20°C, or 33/26°C. Three cultivars were resistant to Fusarium wilt under all test conditions, and thus were little affected by differences in inoculum level or temperature. The remaining cultivars were more susceptible and manifested more severe symptoms at the higher inoculum level and when maintained at higher temperatures. The tendency for the disease to be more severe under warmer conditions may be due, in part, to an effect of temperature on growth of the pathogen. Radial growth rates calculated for six isolates of F. oxysporum f. sp. lactucae were observed to increase from 10°C up to an apparent maximum near 25°C. The results of this study suggest that growers can reduce the risk of damage from Fusarium wilt by avoiding susceptible cultivars during the warmest planting periods. Further, isolates of F. oxysporum f. sp. lactucae were shown to have a distinctive colony morphology in culture, which made it possible to distinguish them from nonpathogenic strains.

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Supakitthanakorn, Salit, On-Uma Ruangwong, and Dheerawan Boonyawan. "Inactivation of Cercospora lactucae-sativa through Application of Non-Thermal Atmospheric Pressure Gliding Arc, Tesla Coil and Dielectric Barrier Discharge Plasmas." Applied Sciences 13, no. 11 (May 30, 2023): 6643. http://dx.doi.org/10.3390/app13116643.

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Cercospora leaf spot disease is a serious problem for lettuce cultivation worldwide. Cercospora lactucae-sativa, the causative agent of leaf spot disease on lettuce, was treated with non-thermal atmospheric pressure gliding arc (GA), tesla coil (TC) and dielectric barrier discharge (DBD) plasmas for the in vitro fungal inactivation of both mycelial growth and conidial germination. The fungus was exposed to the three plasmas individually for 5, 10, 15 and 20 min. The results showed that DBD plasma inactivated fungal growth during all exposure periods, and the highest inhibitory effect was caused by exposure to DBD plasma for 20 min, at 93.33% inhibition. The germination of fungal conidia was completely inactivated after exposure to all three non-thermal plasmas for 5 min, as observed 4 and 24 h after incubation. The pathogenesis of C. lactucae-sativa on lettuce after plasma treatments for 5 min was examined by spraying an inoculation of the treated conidia on lettuce. The results showed that all three plasmas reduced the disease incidence and severity compared to the non-treated control. Therefore, the non-thermal atmospheric pressure GA, TC and DBD plasmas have antifungal potential for the inactivation of C. lactucae-sativa, making them an interesting novel technology for plant disease control.

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Michalska, Klaudia, Katarzyna Pieron, and Anna Stojakowska. "Sesquiterpene Lactones and Phenolics from Roots of Leontodon hispidus subsp. hispidus." Natural Product Communications 13, no. 4 (April 2018): 1934578X1801300. http://dx.doi.org/10.1177/1934578x1801300403.

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The phytochemical investigation on roots of Leontodon hispidus L. subsp. hispidus, led to the isolation of nine sesquiterpene lactones including two eudesmanolides of santamarine type and three lactucin-like guaianolides together with four known phenolic compounds. The eudesmanolides – santamarine and 11 β,13-dihydrosantamarine, guaianolides – matricarin, deacetylmatricarin and deacetylmatricarin 8- O- β-glucopyranoside, and phenolics – syringaldehyde, 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-1-propanone, syringin and dihydroconiferin were found for the first time in Leontodon.

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Deng, Yonghong, Lincoln Scott, Devin Swanson, John K. Snyder, Nil Sari, and Hanzade Dogan. "Guaianolide Sesquiterpene Lactones From Cichorium Intybus (Asteraceae) [1]." Zeitschrift für Naturforschung B 56, no. 8 (August 1, 2001): 787–96. http://dx.doi.org/10.1515/znb-2001-0812.

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Ten guaianolides, including three previously unreported natural products, were isolated from the aerial parts of Cichorium intybus (Asteraceae), more commonly known as chicory. Two of the new compounds ( 8 and 9) were analogues of lactupicrin and 11/β,13-dihydrolactupicrin, respectively, with the C-15 oxidized to the aldehyde state. The third new natural product, which we have called mtybulide A (10), is an isomer of lactucin with the lactone closed to the C-8 oxygen rather than the C-6

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Souza, Jean de O., Tagli Dalpian, Leila T. Braz, and Margarete Camargo. "Novas raças de Bremia lactucae, agente causador do míldio da alface, identificadas no estado de São Paulo." Horticultura Brasileira 29, no. 3 (September 2011): 282–86. http://dx.doi.org/10.1590/s0102-05362011000300004.

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O objetivo deste trabalho foi relatar o surgimento de raças de Bremia lactucae, agente causal do míldio nas principais regiões produtoras de alface do estado de São Paulo. O estudo foi realizado no Laboratório de Melhoramento Genético de Hortaliças do Departamento de Produção Vegetal da UNESP, Campus de Jaboticabal. No período de 2006 e 2007, foram coletados 36 isolados de B. lactucae de diferentes regiões produtoras de alface no estado. Para identificação das raças foram utilizadas as cultivares diferenciadoras conforme o código "Sextet". Foram identificadas três novas raças, SPBl:02, SPBl:03 e SPBl:04 com os referidos comportamentos do fungo: (63/31/19/00), (63/63/19/00) e (63/63/03/00). Os genes Dm-14, Dm-17, Dm-18, Dm-37 e Dm-38 conferem resistência a essas novas raças identificadas.

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Pasquali, Matias, Flavia Dematheis, Giovanna Gilardi, Maria Lodovica Gullino, and Angelo Garibaldi. "Vegetative Compatibility Groups of Fusarium oxysporum f. sp. lactucae from Lettuce." Plant Disease 89, no. 3 (March 2005): 237–40. http://dx.doi.org/10.1094/pd-89-0237.

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Fusarium oxysporum f. sp. lactucae, the causal agent of Fusarium wilt of lettuce, has been reported in three continents in the last 10 years. Forty-seven isolates obtained from infected plants and seed in Italy, the United States, Japan, and Taiwan were evaluated for pathogenicity and vegetative compatibility. Chlorate-resistant, nitrate-nonutilizing mutants were used to determine genetic relatedness among isolates from different locations. Using the vegetative compatibility group (VCG) approach, all Italian and American isolates, type 2 Taiwanese isolates, and a Japanese race 1 were assigned to the major VCG 0300. Taiwanese isolates type 1 were assigned to VCG 0301. The hypothesis that propagules of Fusarium oxysporum f. sp. lactucae that caused epidemics on lettuce in 2001-02 in Italian fields might have spread via import and use of contaminated seeds is discussed.

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Sharaf, K., D. Lewinsohn, E. Nevo, and A. Beharav. "Virulence patterns ofBremia lactucae in Israel." Phytoparasitica 35, no. 1 (February 2007): 100–108. http://dx.doi.org/10.1007/bf02981064.

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Matheron, Michael E., and Martin Porchas. "Evaluation of Soil Solarization and Flooding As Management Tools for Fusarium Wilt of Lettuce." Plant Disease 94, no. 11 (November 2010): 1323–28. http://dx.doi.org/10.1094/pdis-04-10-0296.

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Fusarium wilt of lettuce caused by Fusarium oxysporum f. sp. lactucae continues to spread and cause economic losses in Arizona lettuce fields since the initial discovery of the disease in the state in 2001. Studies were initiated to assess the potential of summer soil solarization and flooding as management tools for Fusarium wilt of lettuce in southwestern Arizona production fields. In microplot studies, lettuce plant growth in soil naturally infested with F. oxysporum f. sp. lactucae that was solarized from 2 to 8 weeks was consistently greater than growth in nonsolarized soil. Growth of lettuce in flooded soil containing the pathogen occasionally was significantly higher than in nonflooded soil; however, the effect on plant growth and health was not as consistent as that recorded for solarized soil. In four trials within a field containing F. oxysporum f. sp. lactucae, the incidence of Fusarium wilt on lettuce sown in soil after solarization was reduced from 42 to 91% compared with disease in nonsolarized plots. There was no significant benefit of a 2- over a 1-month solarization period under the conditions of these trials, where the mean soil temperature at a depth of 5 cm during a 1-month solarization period in 2005 and 2006 was 47 and 49°C, respectively. These findings suggest that soil solarization can be an effective tool for management of Fusarium wilt on lettuce, especially when used within an integrated program in conjunction with existing disease management tactics.

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Simko, Ivan, Oswaldo E. Ochoa, Mathieu A. Pel, Cayla Tsuchida, Carolina Font i Forcada, Ryan J. Hayes, Maria-Jose Truco, Rudie Antonise, Carlos H. Galeano, and Richard W. Michelmore. "Resistance to Downy Mildew in Lettuce ‘La Brillante’ is Conferred by Dm50 Gene and Multiple QTL." Phytopathology® 105, no. 9 (September 2015): 1220–28. http://dx.doi.org/10.1094/phyto-02-15-0057-r.

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Many cultivars of lettuce (Lactuca sativa L.) are susceptible to downy mildew, a nearly globally ubiquitous disease caused by Bremia lactucae. We previously determined that Batavia type cultivar ‘La Brillante’ has a high level of field resistance to the disease in California. Testing of a mapping population developed from a cross between ‘Salinas 88’ and La Brillante in multiple field and laboratory experiments revealed that at least five loci conferred resistance in La Brillante. The presence of a new dominant resistance gene (designated Dm50) that confers complete resistance to specific isolates was detected in laboratory tests of seedlings inoculated with multiple diverse isolates. Dm50 is located in the major resistance cluster on linkage group 2 that contains at least eight major, dominant Dm genes conferring resistance to downy mildew. However, this Dm gene is ineffective against the isolates of B. lactucae prevalent in the field in California and the Netherlands. A quantitative trait locus (QTL) located at the Dm50 chromosomal region (qDM2.2) was detected, though, when the amount of disease was evaluated a month before plants reached harvest maturity. Four additional QTL for resistance to B. lactucae were identified on linkage groups 4 (qDM4.1 and qDM4.2), 7 (qDM7.1), and 9 (qDM9.2). The largest effect was associated with qDM7.1 (up to 32.9% of the total phenotypic variance) that determined resistance in multiple field experiments. Markers identified in the present study will facilitate introduction of these resistance loci into commercial cultivars of lettuce.

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Wood, Kelsey J., Munir Nur, Juliana Gil, Kyle Fletcher, Kim Lakeman, Dasan Gann, Ayumi Gothberg, et al. "Effector prediction and characterization in the oomycete pathogen Bremia lactucae reveal host-recognized WY domain proteins that lack the canonical RXLR motif." PLOS Pathogens 16, no. 10 (October 26, 2020): e1009012. http://dx.doi.org/10.1371/journal.ppat.1009012.

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Pathogens that infect plants and animals use a diverse arsenal of effector proteins to suppress the host immune system and promote infection. Identification of effectors in pathogen genomes is foundational to understanding mechanisms of pathogenesis, for monitoring field pathogen populations, and for breeding disease resistance. We identified candidate effectors from the lettuce downy mildew pathogen Bremia lactucae by searching the predicted proteome for the WY domain, a structural fold found in effectors that has been implicated in immune suppression as well as effector recognition by host resistance proteins. We predicted 55 WY domain containing proteins in the genome of B. lactucae and found substantial variation in both sequence and domain architecture. These candidate effectors exhibit several characteristics of pathogen effectors, including an N-terminal signal peptide, lineage specificity, and expression during infection. Unexpectedly, only a minority of B. lactucae WY effectors contain the canonical N-terminal RXLR motif, which is a conserved feature in the majority of cytoplasmic effectors reported in Phytophthora spp. Functional analysis of 21 effectors containing WY domains revealed 11 that elicited cell death on wild accessions and domesticated lettuce lines containing resistance genes, indicative of recognition of these effectors by the host immune system. Only two of the 11 recognized effectors contained the canonical RXLR motif, suggesting that there has been an evolutionary divergence in sequence motifs between genera; this has major consequences for robust effector prediction in oomycete pathogens.

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JACINTO, ANA CAROLINA PIRES, RENATA CASTOLDI, GABRIEL MASCARENHAS MACIEL, JAIR ROCHA DO PRADO, and HAMILTON CÉSAR DE OLIVEIRA CHARLO. "VERTICAL AND HORIZONTAL RESISTANCE OF F5:6 PROGENIES OF CAROTENOID-BIOFORTIFIED LETTUCE TO Bremia lactucae." Revista Caatinga 35, no. 4 (October 2022): 857–64. http://dx.doi.org/10.1590/1983-21252022v35n413rc.

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ABSTRACT The use of resistant cultivars is one of the strategies for downy mildew management. The objective of this study was to evaluate the vertical and horizontal resistance of F5:6 progenies of carotenoidbiofortified lettuce to virulence phenotypes of Bremia lactucae 63/63/51/00, 63/31/19/00 and 63/63/19/00. The experimental design was completely randomized and subdivided into plots that were evaluated over time. In the plots, 12 genotypes of lettuce were used, and the subplots were monitored over time (7th to the 18th day after inoculation). For each virulence phenotypes of Bremia lactucae, a separate experiment was performed with three replicates. To select resistant genotypes, plants were inoculated with distilled water, sporangia removed from infected tissues and Tween 20. The genotypes were evaluated when sporulation appeared on cotyledonary leaves of the susceptible cultivar Solaris, verifying the proportion of necrotic and sporulated plants. There was a correlation between genotypes and times for all virulence phenotypes evaluated. Genotypes UFU-189#2, UFU-206#1, UFU-215#3 and UFU-215#14 showed vertical resistance to virulence phenotypes 63/63/51/00, 63/31/19/00, and 63/63/19/00 of B. lactucae. Horizontal resistance levels were observed in genotype UFU 206#1 for virulence phenotypes 63/63/51/00 and 63/31/19/00; in genotype UFU-66#7 for virulent phenotype 63/31/19/00; and in genotype UFU-215#10 for virulence phenotype 63/63/19/00.

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Kilian, Norbert. "Revision of Launaea Cass. (Compositae, Lactuceae, Sonchinae)." Englera, no. 17 (1997): 3. http://dx.doi.org/10.2307/3776755.

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Nazarova, E. A. "Karyological study of the genusSteptorhamphusBunge (Lactuceae, Asteraceae)." Caryologia 47, no. 2 (January 1994): 151–58. http://dx.doi.org/10.1080/00087114.1994.10797292.

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ZHU, Shi-Xin. "Lectotypification of Prenanthes henryi Dunn (Compositae-Lactuceae)." Acta Phytotaxonomica Sinica 43, no. 6 (2005): 571. http://dx.doi.org/10.1360/aps040054.

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Kisiel, Wanda, and Klaudia Michalska. "Root constituents of Lactuca sibirica and a comparison of metabolite profiles of L. sibirica and L. tatarica." Acta Societatis Botanicorum Poloniae 78, no. 1 (2011): 25–27. http://dx.doi.org/10.5586/asbp.2009.004.

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Nine known sesquiterpene lactones, including four lactucin-type guaianolides, four costuslactone-type guaianolides and one germacranolide, were isolated from roots of Lactuca sibirica (Asteraceae), six of which were glycoside derivatives. The chemosystematic significance of the compounds is discussed in the context of sesquiterpenoids present in roots of the closely related species Lactuca tatarica. A comparison of sesquiterpene lactone profiles indicate that the species can be differentiated on the basis of their germacranolide glycoside compositions.

Journal articles on the topic 'Lactucine'

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