Добірка наукової літератури з теми ""vegetative-to-mature organ transition""

In contrast to animals, adult organs in plants are not formed during embryogenesis but generated from meristematic cells as plants advance through development. Plant development involves a succession of different phenotypic stages and the transition between these stages is termed phase transition. Phase transitions need to be tightly regulated and coordinated to ensure they occur under optimal seasonal, environmental conditions. Polycarpic perennials transition through vegetative stages and the mature, reproductive stage many times during their lifecycles and, in both perennial and annual species, environmental factors and culturing methods can reverse the otherwise unidirectional vector of plant development. Epigenetic factors regulating gene expression in response to internal cues and external (environmental) stimuli influencing the plant’s phenotype and development have been shown to control phase transitions. How developmental and environmental cues interact to epigenetically alter gene expression and influence these transitions is not well understood, and understanding this interaction is important considering the current climate change scenarios, since epigenetic maladaptation could have catastrophic consequences for perennial plants in natural and agricultural ecosystems. Here, we review studies focusing on the epigenetic regulators of the vegetative phase change and highlight how these mechanisms might act in exogenously induced plant rejuvenation and regrowth following stress.

Euphorbia paralias L. is a poorly studied species that is protected by Red books at the Federal and regional levels, where its conservation status is assessed as «vulnerable» and «declining in number». Euphorbia paralias L has not been studied in terms of population structure, and anatomical studies of the species are not sufficient.The goal is to study the morphological criteria of age states, the spatial and age structure of the coenopulation, and the anatomical structure of vegetative organs. We studied the cоenopopulation on the sandy coast in the South of the Kerch Peninsula (an embankment between the Black sea and Tobechik lake). The phytocoenosis in which Euphorbia paralias L. is few species it contains 11 species per 100 m2. The projective cover of the herbage varies from 40 to 50 %, with Euphorbia paralias L. accounting for 20 to 30 %. The average distance between generative individuals reaches 32.70±0.12 cm; between vegetative individuals – almost 3 times less than 11.40±0.26 cm. The Clark-Evans coefficients between plants were R=10.40; separately for generative plants R=24.25 and for pregenerative individuals R=0.26. Consequently, the spatial structure of the population is contagious, but in the pregenerative phase of development the species forms loci has regulary spaced distribution of individuals. Additionally, the calculated Odum index was equal to 3.03, which confirmed the contagious (clumped distribution) type of growth of individuals in the studied population. In the laboratory, seedlings and juvenile individuals were studied, and the transition to the immature age phase was recorded. Immature, virginal, and generative plants were studied in the natural population. Morphological features for each age state are determined (Fig. 1, 2, 3). The features selected for differentiation of age states showed the reliability of differences at the level of significance p<0.05 and p<0.01 (Tab.1). Their quantitative participation in the population was determined based on the identified morphological features characteristic of plants of different ages. In total 556 specimens of Euphorbia paralias L. were found on the studied area, including 56 juvenile specimens, 31 immature specimens, and 44 virginal specimens. 425 plants are generative (g1=75; g2=250; g3=100). The age spectrum, compiled in accordance with the classical approach (Uranov, 1975; Rabotnov, 1950), is incomplete: seedlings and plants of senile age were not found; the young part of the population is quite large and makes up 23.6 % of the total number of individuals. However, the spectrum is clearly dominated by individuals of Mature generative age, and most of all-a group of generative plants, so the spectrum is clearly monomodal (Fig. 4.). Additionally, this population was evaluated according to the «Delta-omega» classification [Zhukova, 1967; Zhivotovsky, 2001]. The following values were obtained during the calculations: ∆=0.35, ω=0.86. Thus, according to the «Delta-omega» classification, the studied population also belongs to the Mature group. Anatomical study of vegetative organs was carried out. The obtained data on the anatomy of vegetative organs are shown in Fig. 5, 6, 7, 8, 9,10. For Euphorbia paralias, the presence of terpenoid – containing structures represented by one of the forms of receptacles with intracellular accumulation of secretions: non-segmented milkers (Fig. 9, Fig. 11). Non- segmented milkers found in the root and stem are confined to the primary cortex. In the leaf, non-segmented milkers are found in leaf mesophyll and in the subepidermal layer. The new population of Euphorbia paralias L., found on the Kerch Peninsula in 2012, has a high number: 556 individuals grow on the studies area (100 m2), and 11.0±1.2 individuals per 1 m2. The spatial structure of the population is contagious (clumped distribution), which is confirmed by coefficients of the Clark Evans (R=10.40) and Odum (3.03), but in the pregenerative phase the species forms loci with a regulary spaced distribution of individuals (R=0.26). In the anatomical structure of the leaf can be traced: the appearance of a leaf blade similar to the erikoid type, in the process of its ontogenetic metamorphosis; developed cuticle, thickened outer walls of the epidermis, submerged stomata, a high index of the palisade coefficient (81 %,), the presence non-segmented milkers with latex. Complex of xeromorphic features of the leaf, taking into account ecomorph to soil salinity (salt residue 0.1 %), in our opinion, can be attributed Euphorbia paralias to haloxerophytes ecological group. The work was carried out within the framework of the PIT project «Development of a network educational program in the direction of training 06.06.01 Biological Sciences, orientation 03.02.08 Ecology» of the development Program of the Federal state educational INSTITUTION «KFU. V. I. Vernadsky».

Abstract Grapevine (Vitis vinifera L.) is one of the most widely cultivated fruit crops because the winemaking industry has huge economic relevance worldwide. Uncovering the molecular mechanisms controlling the developmental progression of plant organs will prove essential for maintaining high-quality grapes, expressly in the context of climate change, which impairs the ripening process. Through a deep inspection of transcriptomic data, we identified VviNAC60, a member of the NAC transcription factor family, as a putative regulator of grapevine organ maturation. We explored VviNAC60 binding landscapes through DNA affinity purification followed by sequencing and compared bound genes with transcriptomics datasets from grapevine plants stably and transiently overexpressing VviNAC60 to define a set of high-confidence targets. Among these, we identified key molecular markers associated with organ senescence and fruit ripening. Physiological, metabolic, and promoter activation analyses showed that VviNAC60 induces chlorophyll degradation and anthocyanin accumulation through the up-regulation of STAY-GREEN PROTEIN 1 (VviSGR1) and VviMYBA1, respectively, with the latter being up-regulated through a VviNAC60-VviNAC03 regulatory complex. Despite sharing a closer phylogenetic relationship with senescence-related homologues to the NAC transcription factor AtNAP, VviNAC60 complemented the non-ripening(nor) mutant phenotype in tomato (Solanum lycopersicum), suggesting a dual role as an orchestrator of both ripening- and senescence-related processes. Our data support VviNAC60 as a regulator of processes initiated in the grapevine vegetative- to mature-phase organ transition and therefore as a potential target for enhancing the environmental resilience of grapevine by fine-tuning the duration of the vegetative phase.

Flowering is of utmost relevance for the agricultural productivity of the sugarcane bioeconomy, but data and knowledge of the genetic mechanisms underlying its photoperiodic induction are still scarce. An understanding of the molecular mechanisms that regulate the transition from vegetative to reproductive growth in sugarcane could provide better control of flowering for breeding. This study aimed to investigate the transcriptome of +1 mature leaves of a sugarcane cultivar subjected to florally inductive and non-inductive photoperiodic treatments to identify gene expression patterns and molecular regulatory modules. We identified 7,083 differentially expressed (DE) genes, of which 5,623 showed significant identity to other plant genes. Functional group analysis showed differential regulation of important metabolic pathways involved in plant development, such as plant hormones (i.e., cytokinin, gibberellin, and abscisic acid), light reactions, and photorespiration. Gene ontology enrichment analysis revealed evidence of upregulated processes and functions related to the response to abiotic stress, photoprotection, photosynthesis, light harvesting, and pigment biosynthesis, whereas important categories related to growth and vegetative development of plants, such as plant organ morphogenesis, shoot system development, macromolecule metabolic process, and lignin biosynthesis, were downregulated. Also, out of 76 sugarcane transcripts considered putative orthologs to flowering genes from other plants (such as Arabidopsis thaliana, Oryza sativa, and Sorghum bicolor), 21 transcripts were DE. Nine DE genes related to flowering and response to photoperiod were analyzed either at mature or spindle leaves at two development stages corresponding to the early stage of induction and inflorescence primordia formation. Finally, we report a set of flowering-induced long non-coding RNAs and describe their level of conservation to other crops, many of which showed expression patterns correlated against those in the functionally grouped gene network.

La vite (Vitis vinifera L.), una delle più coltivate piante da frutto, riveste notevole importanza economica in tutto il mondo. Poichè negli ultimi decenni la viticoltura sta subendo gli effetti del riscaldamento globale (Webb et al., 2007), è necessario mantenere una produzione di uva e vino di elevata qualità. Una delle maggiori sfide consiste nell’identificazione dei principali geni regolatori dello sviluppo della pianta di vite durante il ciclo vegetale annuale e, in particolare, della transizione dalla fase vegetativa a quella matura (detta véraison), durante la quale avvengono profonde modificazioni biochimiche, fisiologiche e trascrizionali. Grazie ad un'analisi di network di co-espressione sull’atlante del trascrittoma della vite e ad un dataset di dati trascrizionali di bacche (Massonnet, 2015; Palumbo et al., 2014; Fasoli et al., 2012), è stata identificata una nuova categoria di geni chiamata 'switch’; tali geni sono significativamente up-regolati durante la transizione di fase ed inversamente correlati a molti geni soppressi durante la fase matura. Tra questi, i fattori di trascrizione NAM/ATAF/CUC (NAC) rappresentano un’interessante famiglia genica dato il ruolo chiave in processi biologici come sviluppo e risposte allo stress in pianta (Jensen et al., 2014). Per la caratterizzazione funzionale cinque geni NAC sono stati selezionati come putativi principali regolatori della riprogrammazione del trascrittoma durante la maturazione della vite. VvNAC11, VvNAC13, VvNAC33 e VvNAC60 sono stati identificati come geni 'switch' dalla sopra citata analisi, mentre VvNAC03 come gene omologo a NOR (non-ripening) di pomodoro, uno dei principali regolatori della maturazione di tale frutto (Giovannoni, 2004; Giovannoni et al., 1995). I cinque NAC sono stati sovra-espressi transientemente in Vitis vinifera per ottenere una panoramica dei loro effetti primari sul trascrittoma. Sono poi state ottenute e caratterizzate dal punto di vista molecolare e fenotipico piante di vite stabilmente trasformate con VvNAC33 e VvNAC60. VvNAC33 sembra essere coinvolto nella regolazione negativa della fotosintesi poiché le foglie sovra-esprimenti tale gene contengono una minor quantità di clorofilla, mentre VvNAC60 provoca una ridotta crescita della pianta e una prematura lignificazione dello stelo rispetto ad una pianta controllo della stessa età. Questi risultati riflettono comportamenti tipici di piante in fase di maturazione e senescenza, sostenendo l’ipotesi di un ruolo fondamentale dei NAC nella transizione di fase in vite. Al fine di identificare i target che agiscono a valle dei NAC, sono state eseguite analisi microarray sulle foglie delle piante trasformate in modo transiente e stabile. In entrambe le over-espressioni è stata influenzata l’espressione di un'ampia gamma di processi cellulari tra cui, tra le categorie funzionali più rappresentate, vi sono trasporto, metabolismo secondario e attività dei fattori di trascrizione. L'identificazione di VvMYBA1, un noto regolatore della biosintesi degli anotciani in vite (Kobayashi et al., 2002), come target di VvNAC60 suggerisce un ruolo di tale NAC in processi tipici dell’inizio della maturazione. Un altro approccio utilizzato in questo lavoro è stato la complementazione funzionale del mutante nor di pomodoro con i NAC selezionati. Risultati preliminari hanno rivelato che VvNAC03 e VvNAC60 sembrano avere una funzione simile a NOR poichè riescono a maturare almeno esternamente. In conclusione, i risultati ottenuti in questo lavoro suggeriscono la capacità dei VvNAC selezionati di influenzare l'espressione di geni coinvolti nella regolazione che controlla lo sviluppo dalla fase vegeativa alla fase matura in vite. Questo lavoro ha inizato a far luce sul ruolo dei NAC nello sviluppo della vite, ma dovranno essere effettuate ulteriori analisi per ottenere una piena compresione del macchinario molecolare che regola questo complesso sistema di regolazione.
Grapevine is the most widely cultivated and economically important fruit crop in the world. Viticulture has been affected by the global warming currently under way over the past few decades (Webb et al., 2007). Improving the genetics of key grapevine functions is needed to keep producing high quality grapes and wine. In this context, a challenging task is to identify master regulators that program the development of grapevine organs and control transition from vegetative-to-mature growth featured by grape berries during the annual plant cycle. This transition, called véraison, is marked by profound biochemical, physiological and transcriptomic modifications that allow vegetative green berries to enter the ripening process. Thanks to an integrated network analysis performed on the grapevine global gene expression atlas and from a large berry transcriptomic data set (Massonnet, 2015; Palumbo et al., 2014; Fasoli et al., 2012) a new category of genes, called ‘switch’ genes, was identified; they were significantly up-regulated during the developmental shift and inversely correlated with many genes suppressed during the mature growth phase. Among them, plant-specific NAM/ATAF/CUC (NAC) transcription factors represent an interesting gene family due to their key role in the biological processes in plant development and stress responses (Jensen et al., 2014). Five NAC genes were selected for functional characterization as key factor candidates of the major transcriptome reprogramming during grapevine development. VvNAC11, VvNAC13, VvNAC33 and VvNAC60 were identified as ‘switch’ genes in the above-mentioned analysis whereas VvNAC03 was selected because it is a close homologue of tomato NOR (non-ripening), known for its crucial role in tomato fruit ripening regulation (Giovannoni, 2004; Giovannoni et al., 1995). Firstly, the five transcription factors were transiently over-expressed in Vitis vinifera to get an overview of their primary effects on native species. Secondly, we obtained grapevine plants that were stably transformed with VvNAC33 and VvNAC60 and subjected to molecular/phenotypic characterizations. VvNAC33 seemed to be involved in negative regulation of photosynthesis since over-expressing leaves revealed a chlorophyll breakdown, while VvNAC60 affected regular plant development, showing a slight growth and earlier stem lignification in comparison to a same-age plant control. These results reflected typical behaviors of plants undergoing ripening and senescence, thus supporting our working hypothesis proposing a crucial role of NACs in the transition from vegetative to mature development in grapevine. In order to identify downstream targets of the NAC transcription factors analyzed in this work, we performed microarray analysis on leaves of transient and stable ectopic expressing plants. We noted that both over-expressions affected a wide range of cellular processes and among the most represented functional categories we found transport, secondary metabolism and transcription factor activity. The identification of VvMYBA1, a known grapevine regulator of the anthocyanin biosynthetic pathway (Kobayashi et al., 2002), as VvNAC60 target suggests a VvNAC60 role in processes like anthocyanin biosynthesis featured by grape berries at the onset of ripening. Another approach used to clarify NACs roles was to check the ability of VvNACs to fulfil the tomato NOR function. Preliminary results revealed that VvNAC03 and VvNAC60 could partially complement the nor mutation in tomato, establishing a partial ripening phenotype in fruits. Taken together, these findings suggest the ability of the selected VvNACs to affect the expression of genes involved in the regulatory network that controls the developmental shift to a mature phase in grapevine. This work has shed some light on the roles of these NACs in grapevine development, but further analysis must be conducted to fully elucidate the molecular machinery in this complex regulation system.