RESUMEN

Leaf senescence and abscission in autumn are critical phenological events in deciduous woody perennials. After leaf fall, dormant buds remain on deciduous woody perennials, which then enter a winter dormancy phase. Thus, leaf fall is widely believed to be linked to the onset of dormancy. In Rosaceae fruit trees, DORMANCY-ASSOCIATED MADS-box (DAM) transcription factors control bud dormancy. However, apart from their regulatory effects on bud dormancy, the biological functions of DAMs have not been thoroughly characterized. In this study, we revealed a novel DAM function influencing leaf senescence and abscission in autumn. In Prunus mume, PmDAM6 expression was gradually up-regulated in leaves during autumn toward leaf fall. Our comparative transcriptome analysis using two RNA-seq datasets for the leaves of transgenic plants overexpressing PmDAM6 and peach (Prunus persica) DAM6 (PpeDAM6) indicated Prunus DAM6 may up-regulate the expression of genes involved in ethylene biosynthesis and signaling as well as leaf abscission. Significant increases in 1-aminocyclopropane-1-carboxylate accumulation and ethylene emission in DEX-treated 35S:PmDAM6-GR leaves reflect the inductive effect of PmDAM6 on ethylene biosynthesis. Additionally, ethephon treatments promoted autumn leaf senescence and abscission in apple and P. mume, mirroring the changes due to PmDAM6 overexpression. Collectively, these findings suggest that PmDAM6 may induce ethylene emission from leaves, thereby promoting leaf senescence and abscission. This study clarified the effects of Prunus DAM6 on autumn leaf fall, which is associated with bud dormancy onset. Accordingly, in Rosaceae, DAMs may play multiple important roles affecting whole plant growth during the tree dormancy induction phase.

Asunto(s)

Etilenos , Regulación de la Expresión Génica de las Plantas , Hojas de la Planta , Proteínas de Plantas , Senescencia de la Planta , Plantas Modificadas Genéticamente , Prunus , Prunus/genética , Prunus/crecimiento & desarrollo , Prunus/fisiología , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Etilenos/metabolismo , Senescencia de la Planta/genética , Latencia en las Plantas/genética , Reguladores del Crecimiento de las Plantas/metabolismo , Proteínas de Dominio MADS/genética , Proteínas de Dominio MADS/metabolismo , Estaciones del Año , Prunus persica/genética , Prunus persica/crecimiento & desarrollo , Prunus persica/metabolismo

RESUMEN

Leaf senescence represents the final stage of leaf development, involving transcription factors (TFs)-mediated genetic reprogramming events. The timing of crop leaf senescence has a major influence on the yield and quality of crop in agricultural production. As important regulator of plant growth, the significance of TFs in the regulation of leaf senescence have been highlighted in various plant species by recent advances in genetics. However, studies on underlying molecular mechanisms are still not adequately explained. In this study, for analyzing the regulation of TFs on senescence of tobacco leaves, we combined gene differential expression analysis with weighted gene co-expression network analysis (WGCNA) to analyze the time-series gene expression profiles in senescing tobacco leaf. Among 3517 TF genes expressed in tobacco leaves, we identified 21, 35, and 183 TFs that were associated with early, middle, and late stages of tobacco leaf senescence, respectively. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation results reveal that these senescence response TFs are correlated with several biological pathways such as plant hormone signal transduction, ubiquitin mediated proteolysis and MAPK signaling pathway, indicating the roles of TFs in regulating leaf senescence. Our results provide implications for future studies of the potential regulatory mechanisms of TFs involved in senescence of tobacco leaves.

Asunto(s)

Regulación de la Expresión Génica de las Plantas , Nicotiana , Hojas de la Planta , Senescencia de la Planta , Factores de Transcripción , Nicotiana/genética , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Senescencia de la Planta/genética , Redes Reguladoras de Genes , Perfilación de la Expresión Génica , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ontología de Genes , Transcriptoma

RESUMEN

BACKGROUND: Developmental leaf senescence (DLS) is an irreversible process followed by cell death. Dark-induced leaf senescence (DILS) is a reversible process that allows adaptations to changing environmental conditions. As a result of exposure to adverse environmental changes, plants have developed mechanisms that enable them to survive. One of these is the redirection of metabolism into the senescence pathway. The plant seeks to optimise resource allocation. Our research aims to demonstrate how epigenetic machinery regulates leaf senescence, including its irreversibility. RESULTS: In silico analyses allowed the complex identification and characterisation of 117 genes involved in epigenetic processes in barley. These genes include those responsible for DNA methylation, post-translational histone modifications, and ATP-dependent chromatin remodelling complexes. We then performed RNAseq analysis after DILS and DLS to evaluate their expression in senescence-dependent leaf metabolism. Principal component analysis revealed that evaluated gene expression in developmental senescence was similar to controls, while induced senescence displayed a distinct profile. Western blot experiments revealed that senescence engages senescence-specific histone modification. During DILS and DLS, the methylation of histone proteins H3K4me3 and H3K9me2 increased. H3K9ac acetylation levels significantly decreased during DILS and remained unchanged during DLS. CONCLUSIONS: The study identified different epigenetic regulations of senescence types in barley leaves. These findings are valuable for exploring epigenetic regulation of senescence-related molecular mechanisms, particularly in response to premature, induced leaf senescence. Based on the results, we suggest the presence of an epigenetically regulated molecular switch between cell survival and cell death in DILS, highlighting an epigenetically driven cell survival metabolic response.

Asunto(s)

Epigénesis Genética , Hordeum , Hojas de la Planta , Senescencia de la Planta , Hordeum/genética , Hordeum/fisiología , Hojas de la Planta/genética , Hojas de la Planta/fisiología , Senescencia de la Planta/genética , Regulación de la Expresión Génica de las Plantas , Metilación de ADN , Histonas/metabolismo

RESUMEN

Nitrogen (N) deficiency responses are essential for plant survival and reproduction. Here, via an expression genome-wide association study (eGWAS), we reveal a mechanism that regulates microRNA (miRNA) dynamics necessary for N deficiency responses in Arabidopsis. Differential expression levels of three NAC transcription factor (TF) genes involved in leaf N deficiency responses among Arabidopsis accessions are most significantly associated with polymorphisms in HASTY (HST), which encodes an importin/exportin family protein responsible for the generation of mature miRNAs. HST acts as a negative regulator of N deficiency-induced leaf senescence, and the disruption and overexpression of HST differently modifies miRNA dynamics in response to N deficiency, altering levels of miRNAs targeting transcripts. Interestingly, N deficiency prevents the interaction of HST with HST-interacting proteins, DCL1 and RAN1, and some miRNAs. This suggests that HST-mediated regulation of miRNA dynamics collectively controls regulations mediated by multiple N deficiency response-associated NAC TFs, thereby being central to the N deficiency response network.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Regulación de la Expresión Génica de las Plantas , MicroARNs , Nitrógeno , Hojas de la Planta , Factores de Transcripción , Arabidopsis/genética , Arabidopsis/metabolismo , MicroARNs/metabolismo , MicroARNs/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Nitrógeno/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Senescencia de la Planta/genética , Estudio de Asociación del Genoma Completo , Carioferinas/metabolismo , Carioferinas/genética , Ribonucleasa III/metabolismo , Ribonucleasa III/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Proteína de Unión al GTP ran/metabolismo , Proteína de Unión al GTP ran/genética

RESUMEN

The ability of plants to retain nitrogen (N) for a long period of time is critical to their N use efficiency, growth, and fitness, particularly in infertile environments. The mean residence time of leaf N (MRTL) and its two determinants, leaf lifespan and N resorption efficiency (rN, the fraction of the total leaf N pool that is resorbed during leaf senescence), have been hypothesized to increase plastically with decreasing soil N fertility but this remains to be fully tested. To avoid confusion by random changes in these characteristics in a relatively narrow N fertility range, MRTL, leaf lifespan, and N resorption efficiency were measured in Quercus glauca over a broad N fertility range. In the high to moderate N fertility range, leaf lifespan and rN increased with decreasing N addition rate, and thus the MRTL increased. However, in the moderate to low N fertility range, leaf lifespan increased but rN decreased significantly, so MRTL decreased. The decrease in rN occurred because the senesced leaf N concentration was almost constant at the lower limit while the green leaf N concentration decreased in this range. The hump-shaped quadratic responses of MRTL and rN along the N fertility gradient suggest that incorrect conclusions about the response of these traits to N fertility variation may be drawn from experiments that include only a few fertility levels, and N recycling within leaf canopy alone cannot achieve efficient N use in infertile environments.

Asunto(s)

Nitrógeno , Hojas de la Planta , Quercus , Suelo , Hojas de la Planta/fisiología , Hojas de la Planta/metabolismo , Nitrógeno/metabolismo , Quercus/fisiología , Quercus/metabolismo , Suelo/química , Árboles/fisiología , Árboles/metabolismo , Senescencia de la Planta/fisiología

RESUMEN

Leaf senescence is a crucial process throughout evolution, vital for plant fitness as it facilitates the gradual shift of energy allocation between photosynthesis and catabolism overtime. This onset is influenced by a complex interplay of genetic and environmental factors, making senescence a key adaptation mechanism for plants in their natural habitats. Our study investigated the genetic mechanism underlying age-induced leaf senescence in Arabidopsis natural populations. Using a phenome high-throughput investigator, we comprehensively analyzed senescence responses across 234 Arabidopsis accessions and identified that environmental factors (e.g., ambient temperature) and physiological factors (e.g., defense responses) are substantially linked to senescence phenotypes. Through genome-wide association mapping, we identified the ACCELERATED CELL DEATH 6 (ACD6) locus as a potential regulator of senescence variation among natural accessions. Knocking out ACD6 in accessions with early and delayed senescence phenotypes resulted in varying degrees of delay in age-induced senescence, highlighting the accession-dependent regulatory role of ACD6 in leaf senescence. Furthermore, our findings suggest ACD6's involvement in senescence regulation via the salicylic acid signaling pathway. In summary, our study sheds light on the genetic regulation of leaf senescence in Arabidopsis natural populations, with the discovery of ACD6 as a potential candidate for genetic modification to enhance plant adaptation and survival.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Hojas de la Planta , Senescencia de la Planta , Ácido Salicílico , Arabidopsis/genética , Arabidopsis/fisiología , Hojas de la Planta/genética , Hojas de la Planta/fisiología , Hojas de la Planta/efectos de los fármacos , Ácido Salicílico/metabolismo , Ácido Salicílico/farmacología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Senescencia de la Planta/genética , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Fenotipo , Estudio de Asociación del Genoma Completo , Transducción de Señal , Ancirinas

RESUMEN

Leaves are a key forage part for livestock, and the aging of leaves affects forage biomass and quality. Preventing or delaying premature leaf senescence leads to an increase in pasture biomass accumulation and an improvement in alfalfa quality. NAC transcription factors have been reported to affect plant growth and abiotic stress responses. In this study, 48 NAC genes potentially associated with leaf senescence were identified in alfalfa under dark or salt stress conditions. A phylogenetic analysis divided MsNACs into six subgroups based on similar gene structure and conserved motif. These MsNACs were unevenly distributed in 26 alfalfa chromosomes. The results of the collinearity analysis show that all of the MsNACs were involved in gene duplication. Some cis-acting elements related to hormones and stress were screened in the 2-kb promoter regions of MsNACs. Nine of the MsNAC genes were subjected to qRT-PCR to quantify their expression and Agrobacterium-mediated transient expression to verify their functions. The results indicate that Ms.gene031485, Ms.gene032313, Ms.gene08494, and Ms.gene77666 might be key NAC genes involved in alfalfa leaf senescence. Our findings extend the understanding of the regulatory function of MsNACs in leaf senescence.

Asunto(s)

Regulación de la Expresión Génica de las Plantas , Medicago sativa , Filogenia , Hojas de la Planta , Proteínas de Plantas , Factores de Transcripción , Medicago sativa/genética , Medicago sativa/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Transcriptoma , Familia de Multigenes , Senescencia de la Planta/genética , Estrés Salino/genética , Perfilación de la Expresión Génica , Oscuridad

RESUMEN

Plant senescence is a highly coordinated process that is intricately regulated by numerous endogenous and environmental signals. The involvement of phytic acid in various cell signaling and plant processes has been recognized, but the specific roles of phytic acid metabolism in Arabidopsis leaf senescence remain unclear. Here, we demonstrate that in Arabidopsis thaliana the multiple inositol phosphate phosphatase (AtMINPP) gene, encoding an enzyme with phytase activity, plays a crucial role in regulating leaf senescence by coordinating the ethylene signal transduction pathway. Through overexpressing AtMINPP (AtMINPP-OE), we observed early leaf senescence and reduced chlorophyll contents. Conversely, a loss-of-function heterozygous mutant (atminpp/+) exhibited the opposite phenotype. Correspondingly, the expression of senescence-associated genes (SAGs) was significantly upregulated in AtMINPP-OE but markedly decreased in atminpp/+. Yeast one-hybrid and chromatin immunoprecipitation assays indicated that the EIN3 transcription factor directly binds to the promoter of AtMINPP. Genetic analysis further revealed that AtMINPP-OE could accelerate the senescence of ein3-1eil1-3 mutants. These findings elucidate the mechanism by which AtMINPP regulates ethylene-induced leaf senescence in Arabidopsis, providing insights into the genetic manipulation of leaf senescence and plant growth.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Etilenos , Regulación de la Expresión Génica de las Plantas , Ácido Fítico , Hojas de la Planta , Transducción de Señal , Etilenos/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/crecimiento & desarrollo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Ácido Fítico/metabolismo , Senescencia de la Planta/genética , Monoéster Fosfórico Hidrolasas/metabolismo , Monoéster Fosfórico Hidrolasas/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Regiones Promotoras Genéticas , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética

RESUMEN

Numerous studies have investigated seed aging, with a particular emphasis on the involvement of reactive oxygen species. Reactive oxygen species diffuse into the nucleus and damage telomeres, resulting in loss of genetic integrity. Telomerase reverse transcriptase (TERT) plays an essential role in maintaining plant genomic stability. Genome-wide analyses of TERT genes in alfalfa (Medicago sativa) have not yet been conducted, leaving a gap in our understanding of the mechanisms underlying seed aging associated with TERT genes. In this study, four MsTERT genes were identified in the alfalfa genome. The expression profiles of the four MsTERT genes during seed germination indicated that MS. gene79077 was significantly upregulated by seed aging. Transgenic seeds overexpressing MS. gene79077 in Arabidopsis exhibited enhanced tolerance to seed aging by reducing the levels of H2O2 and increasing telomere length and telomerase activity. Furthermore, transcript profiling of aging-treated Arabidopsis wild-type and overexpressing seeds showed an aging response in genes related to glutathione-dependent detoxification and antioxidant defense pathways. These results revealed that MS. gene79077 conferred Arabidopsis seed-aging tolerance via modulation of antioxidant defense and telomere homeostasis. This study provides a new way to understand stress-responsive MsTERT genes for the potential genetic improvement of seed vigor.

Asunto(s)

Arabidopsis , Regulación de la Expresión Génica de las Plantas , Medicago sativa , Semillas , Telomerasa , Homeostasis del Telómero , Telómero , Arabidopsis/genética , Medicago sativa/genética , Telomerasa/genética , Telomerasa/metabolismo , Semillas/genética , Telómero/genética , Telómero/metabolismo , Plantas Modificadas Genéticamente , Germinación/genética , Peróxido de Hidrógeno/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Antioxidantes/metabolismo , Senescencia de la Planta/genética

RESUMEN

Climate change is bringing more frequent and intense droughts, reducing overall water availability and adversely affecting crops. There is a need to improve our understanding of the tissular and cellular adaptation mechanisms that are critical for plant water conservation strategies. Here, we have used NMR relaxometry in combination with microscopy and multi-omic analysis to study the effects of progressive soil drought on winter oilseed rape (WOSR, Brassica napus L., cv. Aviso) leaves. This study reveals the structural and metabolic adjustments these leaves operate to maintain cell homeostasis. Our results are original in showing that the adaptive responses are altered in leaves at the onset of senescence, associated with changes in metabolic plasticity and mesophyll structures. Thus, long-term responses in young leaves involving osmotic adjustment were combined with the maintenance of tissue hydration and cell growth, contributing to high survival and recovery capacity. For the first time, short-term responses observed in early senescent-old leaves were associated with early drought-induced dehydration of the spongy layer. However, this dehydration was not followed by osmotic adjustment and did not allow maintenance of leaf tissue turgor. These findings open further studies on the genetic variability of drought responses related to identified short- and long-term structural and metabolic plasticity traits in Brassica species.

Asunto(s)

Adaptación Fisiológica , Brassica napus , Sequías , Hojas de la Planta , Brassica napus/fisiología , Brassica napus/genética , Espectroscopía de Resonancia Magnética/métodos , Multiómica , Hojas de la Planta/fisiología , Hojas de la Planta/metabolismo , Senescencia de la Planta/genética , Senescencia de la Planta/fisiología , Estaciones del Año , Agua/metabolismo

RESUMEN

Early leaf senescence affects photosynthetic efficiency and limits growth during the late production stage of winter wheat (Triticum aestivum). Natural variation in photosystem response to senescence represents a valuable resource for improving the aging traits of flag leaves. To explore the natural variation of different phases of photosynthetic electron transport in modern wheat cultivars during senescence, we exposed the flag leaves of 32 wheat cultivars to dark conditions to induce senescence process, and simultaneously measured prompt fluorescence and modulated 820 nm reflection. The results showed that the chlorophyll content, activity of PSII donor side, PSI and electron transfer between PSII and PSI were all decreased during dark-induced senescence, but they showed different sensitivity to dark-induced senescence. Furthermore, natural variation in photosynthetic parameters among the 32 wheat cultivars were also observed and showed by variation coefficient of the different parameters. We observed that PSII and PSI activity showed less sensitivity to dark-induced senescence than electron transfer between them, while PSII and PSI activity exhibit greater natural variation than electron transport between PSII and PSI. It suggests that Cytb6f might degrade faster and have less variation than PSII and PSI during dark-induced senescence.

Asunto(s)

Clorofila , Oscuridad , Fotosíntesis , Complejo de Proteína del Fotosistema II , Hojas de la Planta , Triticum , Hojas de la Planta/metabolismo , Triticum/metabolismo , Triticum/fisiología , Triticum/crecimiento & desarrollo , Transporte de Electrón , Complejo de Proteína del Fotosistema II/metabolismo , Clorofila/metabolismo , Complejo de Proteína del Fotosistema I/metabolismo , Senescencia de la Planta

RESUMEN

Monocarpic senescence, characterized by whole-plant senescence following a single flowering phase, is widespread in seed plants, particularly in crops, determining seed harvest time and quality. However, how external and internal signals are systemically integrated into monocarpic senescence remains largely unknown. Here, we report that the Arabidopsis thaliana transcription factor WRKY1 plays essential roles in multiple key steps of monocarpic senescence. WRKY1 expression is induced by age, salicylic acid (SA), and nitrogen (N) deficiency. Flowering and leaf senescence are accelerated in the WRKY1 overexpression lines but are delayed in the wrky1 mutants. The combined DNA affinity purification sequencing and RNA sequencing analyses uncover the direct target genes of WRKY1. Further studies show that WRKY1 coordinately regulates three processes in monocarpic senescence: (1) suppressing FLOWERING LOCUS C gene expression to initiate flowering, (2) inducing SA biosynthesis genes to promote leaf senescence, and (3) activating the N assimilation and transport genes to trigger N remobilization. In summary, our study reveals how one stress-responsive transcription factor, WRKY1, integrates flowering, leaf senescence, and N remobilization processes into monocarpic senescence, providing important insights into plant lifetime regulation.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Flores , Regulación de la Expresión Génica de las Plantas , Nitrógeno , Hojas de la Planta , Senescencia de la Planta , Factores de Transcripción , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Arabidopsis/fisiología , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Flores/metabolismo , Flores/genética , Flores/crecimiento & desarrollo , Nitrógeno/metabolismo , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Senescencia de la Planta/genética , Ácido Salicílico/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética

RESUMEN

Vegetation autumn phenology is critical in regulating the ecosystem carbon cycle and regional climate. However, the dominant drivers of autumn senescence and their temporal shifts under climate change remain poorly understood. Here, we conducted a multi-factor analysis considering both direct climatic controls and biological carryover effects from start-of-season (SOS) and seasonal peak vegetation activities on the end-of-season (EOS) to fill these knowledge gaps. Combining satellite and ground observations across the northern hemisphere, we found that carryover effects from early-to-peak vegetation activities exerted greater influence on EOS than the direct climatic controls on nearly half of the vegetated land. Unexpectedly, the carryover effects from SOS on EOS have significantly weakened over recent decades, accompanied by strengthened climatic controls. Such results indicate the weakened constraint of leaf longevity on senescence due to prolonged growing season in response to climate change. These findings underscore the important role of biological carryover effects in regulating vegetation autumn senescence under climate change, which should be incorporated into the formulation and enhancement of phenology modules utilized in land surface models.

Asunto(s)

Cambio Climático , Hojas de la Planta , Estaciones del Año , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/fisiología , Senescencia de la Planta , Ecosistema

RESUMEN

Premature leaf senescence significantly reduces rice yields. Despite identifying numerous factors influencing these processes, the intricate genetic regulatory networks governing leaf senescence demand further exploration. We report the characterization of a stably inherited, ethyl methanesulfonate(EMS)-induced rice mutant with wilted leaf tips from seedling till harvesting, designated lts2. This mutant exhibits dwarfism and early senescence at the leaf tips and margins from the seedling stage when compared to the wild type. Furthermore, lts2 displays a substantial decline in both photosynthetic activity and chlorophyll content. Transmission electron microscopy revealed the presence of numerous osmiophilic granules in chloroplast cells near the senescent leaf tips, indicative of advanced cellular senescence. There was also a significant accumulation of H2O2, alongside the up-regulation of senescence-associated genes within the leaf tissues. Genetic mapping situated lts2 between SSR markers Q1 and L12, covering a physical distance of approximately 212 kb in chr.1. No similar genes controlling a premature senescence leaf phenotype have been identified in the region, and subsequent DNA and bulk segregant analysis (BSA) sequencing analyses only identified a single nucleotide substitution (C-T) in the exon of LOC_Os01g35860. These findings position the lts2 mutant as a valuable genetic model for elucidating chlorophyll metabolism and for further functional analysis of the gene in rice.

Asunto(s)

Clorofila , Mutación , Oryza , Hojas de la Planta , Oryza/genética , Oryza/metabolismo , Oryza/crecimiento & desarrollo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Clorofila/metabolismo , Senescencia de la Planta/genética , Mapeo Cromosómico , Fenotipo , Regulación de la Expresión Génica de las Plantas , Fotosíntesis/genética , Genes de Plantas , Peróxido de Hidrógeno/metabolismo

RESUMEN

BACKGROUND: Phosphorus is a macronutrient necessary for plant growth and development and its availability and efficient use affect crop yields. Leaves are the largest tissue that uses phosphorus in plants, and membrane phospholipids are the main source of cellular phosphorus usage. RESULTS: Here we identify a key process for plant cellular phosphorus recycling mediated by membrane phospholipid hydrolysis during leaf senescence. Our results indicate that over 90% of lipid phosphorus, accounting for more than one-third of total cellular phosphorus, is recycled from senescent leaves before falling off the plants. Nonspecific phospholipase C4 (NPC4) and phospholipase Dζ2 (PLDζ2) are highly induced during leaf senescence, and knockouts of PLDζ2 and NPC4 decrease the loss of membrane phospholipids and delay leaf senescence. Conversely, overexpression of PLDζ2 and NPC4 accelerates the loss of phospholipids and leaf senescence, promoting phosphorus remobilization from senescent leaves to young tissues and plant growth. We also show that this phosphorus recycling process in senescent leaves mediated by membrane phospholipid hydrolysis is conserved in plants. CONCLUSIONS: These results indicate that PLDζ2- and NPC4-mediated membrane phospholipid hydrolysis promotes phosphorus remobilization from senescent leaves to growing tissues and that the phospholipid hydrolysis-mediated phosphorus recycling improves phosphorus use efficiency in plants.

Asunto(s)

Fosfatos , Fosfolipasa D , Hojas de la Planta , Hojas de la Planta/metabolismo , Fosfatos/metabolismo , Fosfolipasa D/metabolismo , Fosfolipasa D/genética , Senescencia de la Planta , Arabidopsis/metabolismo , Arabidopsis/genética , Fósforo/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Fosfolípidos/metabolismo , Fosfolipasas/metabolismo , Hidrólisis , Regulación de la Expresión Génica de las Plantas

RESUMEN

BACKGROUND: Isopentenyltransferases (IPT) serve as crucial rate-limiting enzyme in cytokinin synthesis, playing a vital role in plant growth, development, and resistance to abiotic stress. RESULTS: Compared to the wild type, transgenic creeping bentgrass exhibited a slower growth rate, heightened drought tolerance, and improved shade tolerance attributed to delayed leaf senescence. Additionally, transgenic plants showed significant increases in antioxidant enzyme levels, chlorophyll content, and soluble sugars. Importantly, this study uncovered that overexpression of the MtIPT gene not only significantly enhanced cytokinin and auxin content but also influenced brassinosteroid level. RNA-seq analysis revealed that differentially expressed genes (DEGs) between transgenic and wild type plants were closely associated with plant hormone signal transduction, steroid biosynthesis, photosynthesis, flavonoid biosynthesis, carotenoid biosynthesis, anthocyanin biosynthesis, oxidation-reduction process, cytokinin metabolism, and wax biosynthesis. And numerous DEGs related to growth, development, and stress tolerance were identified, including cytokinin signal transduction genes (CRE1, B-ARR), antioxidase-related genes (APX2, PEX11, PER1), Photosynthesis-related genes (ATPF1A, PSBQ, PETF), flavonoid synthesis genes (F3H, C12RT1, DFR), wax synthesis gene (MAH1), senescence-associated gene (SAG20), among others. CONCLUSION: These findings suggest that the MtIPT gene acts as a negative regulator of plant growth and development, while also playing a crucial role in the plant's response to abiotic stress.

Asunto(s)

Agrostis , Transferasas Alquil y Aril , Citocininas , Sequías , Hojas de la Planta , Senescencia de la Planta , Plantas Modificadas Genéticamente , Agrostis/genética , Agrostis/fisiología , Agrostis/metabolismo , Transferasas Alquil y Aril/genética , Transferasas Alquil y Aril/metabolismo , Plantas Modificadas Genéticamente/genética , Senescencia de la Planta/genética , Hojas de la Planta/genética , Hojas de la Planta/fisiología , Citocininas/metabolismo , Regulación de la Expresión Génica de las Plantas , Reguladores del Crecimiento de las Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estrés Fisiológico/genética , Fotosíntesis/genética , Genes de Plantas , Resistencia a la Sequía

Asunto(s)

Arabidopsis , Etilenos , Hojas de la Planta , Arabidopsis/genética , Arabidopsis/fisiología , Arabidopsis/crecimiento & desarrollo , Etilenos/metabolismo , Etilenos/biosíntesis , Hojas de la Planta/fisiología , Hojas de la Planta/crecimiento & desarrollo , Senescencia de la Planta , Regulación de la Expresión Génica de las Plantas , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética

RESUMEN

BACKGROUND: Whole plant senescence represents the final stage in the life cycle of annual plants, characterized by the decomposition of aging organs and transfer of nutrients to seeds, thereby ensuring the survival of next generation. However, the transcriptomic profile of vegetative organs during this death process remains to be fully elucidated, especially regarding the distinctions between natural programmed death and artificial sudden death induced by herbicide. RESULTS: Differential genes expression analysis using RNA-seq in leaves and roots of Arabidopsis thaliana revealed that natural senescence commenced in leaves at 45-52 days after planting, followed by roots initiated at 52-60 days. Additionally, both organs exhibited similarities with artificially induced senescence by glyphosate. Transcription factors Rap2.6L and WKRY75 appeared to serve as central mediators of regulatory changes during natural senescence, as indicated by co-expression networks. Furthermore, the upregulation of RRTF1, exclusively observed during natural death, suggested its role as a regulator of jasmonic acid and reactive oxygen species (ROS) responses, potentially triggering nitrogen recycling in leaves, such as the glutamate dehydrogenase (GDH) shunt. Root senescence was characterized by the activation of AMT2;1 and GLN1;3, facilitating ammonium availability for root-to-shoot translocation, likely under the regulation of PDF2.1. CONCLUSIONS: Our study offers valuable insights into the transcriptomic interplay between phytohormones and ROS during whole plant senescence. We observed distinct regulatory networks governing nitrogen utilization in leaf and root senescence processes. Furthermore, the efficient allocation of energy from vegetative organs to seeds emerges as a critical determinant of population sustainability of annual Arabidopsis.

Asunto(s)

Arabidopsis , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Herbicidas , Senescencia de la Planta , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/efectos de los fármacos , Arabidopsis/metabolismo , Herbicidas/farmacología , Herbicidas/toxicidad , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Senescencia de la Planta/genética , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Raíces de Plantas/genética , Transcriptoma , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo

RESUMEN

Evergreeness is a substantial strategy for temperate and boreal plants and is as common as deciduousness. However, whether evergreen plants switch foliage functions between seasons remains unknown. We conduct an in natura study of leaf senescence control in the evergreen perennial, Arabidopsis halleri. A four-year census of leaf longevity of 102 biweekly cohorts allows us to identify growth season (GS) and overwintering (OW) cohorts characterised by short and extended longevity, respectively, and to recognise three distinct periods in foliage functions, i.e., the growth, overwintering, and reproductive seasons. Photoperiods during leaf expansion separate the GS and OW cohorts, providing primal control of leaf senescence depending on the season, with leaf senescence being shut down during winter. Phenotypic and transcriptomic responses in field experiments indicate that shade-induced and reproductive-sink-triggered senescence are active during the growth and reproductive seasons, respectively. These secondary controls of leaf senescence cause desynchronised and synchronised leaf senescence during growth and reproduction, respectively. Conclusively, seasonal switching of leaf senescence optimises resource production, storage, and translocation for the season, making the evergreen strategy adaptively relevant.

Asunto(s)

Arabidopsis , Regulación de la Expresión Génica de las Plantas , Fotoperiodo , Hojas de la Planta , Senescencia de la Planta , Estaciones del Año , Arabidopsis/fisiología , Arabidopsis/crecimiento & desarrollo , Arabidopsis/genética , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/fisiología , Transcriptoma , Reproducción/fisiología , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Fenotipo

RESUMEN

Heat stress substantially reduces tomato (Solanum lycopersicum) growth and yield globally, thereby jeopardizing food security. DnaJ proteins, constituents of the heat shock protein system, protect cells from diverse environmental stresses as HSP-70 molecular co-chaperones. In this study, we demonstrated that AdDjSKI, a serine-rich DnaJ III protein induced by pathogens, plays an important role in stabilizing photosystem II (PSII) in response to heat stress. Our results revealed that transplastomic tomato plants expressing the AdDjSKI gene exhibited increased levels of total soluble proteins, improved growth and chlorophyll content, reduced malondialdehyde (MDA) accumulation, and diminished PSII photoinhibition under elevated temperatures when compared with wild-type (WT) plants. Intriguingly, these transplastomic plants maintained higher levels of D1 protein under elevated temperatures compared with the WT plants, suggesting that overexpression of AdDjSKI in plastids is crucial for PSII protection, likely due to its chaperone activity. Furthermore, the transplastomic plants displayed lower accumulation of superoxide radical (O2 •─) and H2O2, in comparison with the WT plants, plausibly attributed to higher superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities. This also coincides with an enhanced expression of corresponding genes, including SlCuZnSOD, SlFeSOD, SlAPX2, and SltAPX, under heat stress. Taken together, our findings reveal that chloroplastic expression of AdDjSKI in tomatoes plays a critical role in fruit yield, primarily through a combination of delayed senescence and stabilizing PSII under heat stress.

Asunto(s)

Frutas , Respuesta al Choque Térmico , Complejo de Proteína del Fotosistema II , Hojas de la Planta , Proteínas de Plantas , Plastidios , Solanum lycopersicum , Solanum lycopersicum/genética , Solanum lycopersicum/fisiología , Solanum lycopersicum/crecimiento & desarrollo , Solanum lycopersicum/metabolismo , Complejo de Proteína del Fotosistema II/metabolismo , Complejo de Proteína del Fotosistema II/genética , Respuesta al Choque Térmico/genética , Frutas/genética , Frutas/crecimiento & desarrollo , Frutas/fisiología , Frutas/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Hojas de la Planta/genética , Hojas de la Planta/fisiología , Hojas de la Planta/metabolismo , Plastidios/metabolismo , Plastidios/genética , Clorofila/metabolismo , Proteínas del Choque Térmico HSP40/metabolismo , Proteínas del Choque Térmico HSP40/genética , Plantas Modificadas Genéticamente , Senescencia de la Planta/genética , Regulación de la Expresión Génica de las Plantas , Malondialdehído/metabolismo