Plant Senescence Research Articles

A Large-Scale Agricultural Land Classification Method Based on Synergistic Integration of Time Series Red-Edge Vegetation Index and Phenological Features

Agricultural land classification plays a pivotal role in food security and ecological sustainability, yet achieving accurate large-scale mapping remains challenging. This study presents methodological innovations through a multi-level feature enhancement framework that transcends traditional time series analysis. Using Shandong Province, northern China’s agricultural heartland, as a case study, we first established a foundation with time series red-edge vegetation indices (REVI) from Sentinel-2 imagery, uniquely combining the normalized difference red edge index (NDRE705) and plant senescence reflectance index (PSRI). Moving beyond conventional time series analysis, we innovatively amplified key temporal characteristics through newly designed spatial feature parameters (SFPs) and phenological feature parameters (PFPs). This strategic enhancement of critical temporal points significantly improved classification performance by capturing subtle spatial patterns and phenological transitions that are often overlooked in traditional approaches. The study yielded three significant findings: (1) The synergistic application of NDRE705 and PSRI significantly outperformed single-index approaches, demonstrating the effectiveness of our dual-index strategy; (2) The integration of SFPs and PFPs with time series REVI markedly enhanced feature discrimination at crucial growth stages, with PFPs showing superior capability in distinguishing agricultural land types through amplified phenological signatures; (3) Our optimal classification scheme (FC6), leveraging both enhanced spatial and phenological features, achieved remarkable accuracy (93.21%) with a Kappa coefficient of 0.9159, representing improvements of 4.83% and 0.0538, respectively, over the baseline approach. This comprehensive framework successfully mapped 120,996 km2 of agricultural land, differentiating winter wheat–summer maize rotation areas (39.44%), single-season crop fields (36.16%), orchards (14.49%), and facility vegetable fields (9.91%). Our approach advances the field by introducing a robust, scalable methodology that not only utilizes the full potential of time series data but also strategically enhances critical temporal features for improved classification accuracy, particularly valuable for regions with complex farming systems and diverse crop patterns.

Genome-wide analyses of the NAC transcription factor gene family in Acer palmatum provide valuable insights into the natural process of leaf senescence

Acer palmatum is a deciduous shrub or small tree. It is a popular ornamental plant because of its beautiful leaves, which change colour in autumn. This study revealed 116 ApNAC genes within the genome of A. palmatum. These genes are unevenly distributed on the 13 chromosomes of A. palmatum. An analysis of the phylogenetic tree of Arabidopsis thaliana NAC family members revealed that ApNAC proteins could be divided into 16 subgroups. A comparison of ApNAC proteins with NAC genes from other species suggested their potential involvement in evolutionary processes. Studies suggest that tandem and segmental duplications may be key drivers of the expansion of the ApNAC gene family. Analysis of the transcriptomic data and qRT‒PCR results revealed significant upregulation of most ApNAC genes during autumn leaf senescence compared with their expression levels in summer leaves. Coexpression network analysis revealed that the expression profiles of 10 ApNAC genes were significantly correlated with those of 200 other genes, most of which are involved in plant senescence processes. In conclusion, this study contributes to elucidating the theoretical foundation of the ApNAC gene family and provides a valuable basis for future investigations into the role of NAC genes in regulating leaf senescence in woody ornamental plants.

Double‐Edged Sword Effect of Jasmonoyl‐Isoleucine on the Parasite–Host Interaction Between Field Dodder and Lentil

ABSTRACTMany holoparasitic plants are well‐known for their negative impacts on crops, yet the underlying mechanisms behind the interaction between holoparasitic plants and their hosts are still poorly understood. This study investigates the role of stress‐induced phytohormones on the relationship between field dodder (Cuscuta campestris) and lentil plants (Lens culinaris), a model for parasitic plant‐host interaction in legumes. We evaluated the impact of parasitism on host phenology, vegetative growth, and yield. In addition, stress markers and spatiotemporal variations in endogenous levels of stress‐related phytohormones were measured. Parasitism had a drastic effect on yield by accelerating plant phenology, enhancing plant senescence, and deregulating pod maturation. Moreover, an antagonistic relationship between jasmonates and abscisic acid (ABA) was observed in field dodder during the attachment of haustoria to the host, such that the content of the bioactive jasmonate, jasmonoyl‐isoleucine (contrary to ABA), was very high in free haustoria (prior to attachment). Finally, the content of jasmonoyl‐isoleucine increased in the host plant, although this defense response in young leaves was not sufficient to prevent severe loss of PSII integrity. This demonstrates that jasmonoyl‐isoleucine is up‐regulated in both free‐haustoria field dodder and infested lentil plants, suggesting that this bioactive jasmonate form has a universal protective role in both sides of the interaction between parasitic plant and host.

Ecophysiological and Molecular Analysis of Contrasting Genotypes for Leaf Senescence in Sunflower (Helianthus annuus L.) Under Differential Doses of N in Soil.

Leaf senescence in plants is the last stage of leaf development and is characterized by a decline in photosynthetic activity, an active degeneration of cellular structures, and the recycling of accumulated nutrients to areas of active growth, such as buds, young leaves, flowers, fruits, and seeds. This process holds economic significance as it can impact yield, influencing the plant's ability to maintain an active photosynthetic system during prolonged periods, especially during the grain filling stage, which affects plant weight and oil content. It can be associated with different stresses or environmental conditions, manifesting itself widely in the context of climate change and limiting yield, especially in crops of agronomic relevance. In this work, we study the stability of two widely described sunflower (Helianthus annuus L.) genotypes belonging to the INTA Breeding Program against differential N conditions, to verify their yield stability in control conditions and under N supply. Two inbred lines were utilized, namely R453 (early senescence) and B481-6 (late senescence), with contrasting nitrogen availability in the soil but sharing the same ontogeny cycle length. It was observed that, starting from R5.5, the B481-6 genotype not only delayed senescence but also exhibited a positive response to increased nitrogen availability in the soil. This response included an increase in intercepted radiation, resulting in a statistically significant enhancement in grain yield. Conversely, the R453 genotype did not show significant differences under varying nitrogen availability and exhibited a tendency to decrease grain yield when nitrogen availability was increased. The response to nitrogen can vary depending on the specific genotype.

Alternative Splicing of PheNAC23 from Moso Bamboo Impacts Flowering Regulation and Drought Tolerance in Transgenic Arabidopsis.

NAC (NAM, ATAF, and CUC) transcription factors are essential in regulating plant stress response and senescence, with their functions being modulated by alternative splicing. The molecular mechanisms of stress-induced premature flowering and drought tolerance in Phyllostachys edulis (moso bamboo) are not yet fully understood. In this study, a novel NAC variant derived from PheNAC23, named PheNAC23ES, was isolated. PheNAC23ES exhibited distinct expression patterns compared to PheNAC23 during leaf senescence and drought stress response. Overexpression of PheNAC23 promoted flowering and reduced its tolerance to drought stress in Arabidopsis thaliana (A. thaliana). However, overexpression of PheNAC23ES exhibited the opposite functions. PheNAC23 was localized in the nucleus and had transactivation activity, while PheNAC23ES had a similar localization to the control green fluorescent protein and no transactivation activity. Further functional analysis revealed that PheNAC23ES could interact with PheNAC23, suggesting that PheNAC23ES might serve as a small interfering peptide that affects the function of PheNAC23 by binding to it.

Machine learning based approach for wheat plant senescence quantification

Machine learning based approach for wheat plant senescence quantification

Mechanistic insights into leaf senescence regulation in woody plants: a molecular perspective.

Leaves, the primary carbon fixers in autotrophic plants, undergo a complex senescence process, which is critical for the redistribution of nutrients and supports ongoing growth and development. This natural aging phenomenon, often triggered at the end of a plant's life cycle or during the autumn season in perennial species, is finely regulated at multiple levels. Premature senescence can disrupt normal plant development, while the timing and pace of senescence significantly impact crop yield and quality. Notably, accelerated senescence under stress conditions may enhance the survival of future generations, suggesting an evolutionary strategy for plants to cope with harsh environments. Our review focuses on the molecular regulation of leaf senescence in woody plants, emphasizing the intricate determinants and regulatory mechanisms involved, including the role of phytohormones, environmental cues and genetic factors. We highlight recent advances in understanding the regulation of leaf senescence in woody plants, integrating insights from multidisciplinary approaches and cutting-edge technologies.

Assessing the effectiveness of vegetation indices in detecting forest disturbances in the southeast Amazon

Amazon forests are becoming increasingly vulnerable to disturbances such as droughts, fires, windstorms, logging, and forest fragmentation, all of which lead to forest degradation. Nevertheless, quantifying the extent and severity of disturbances and their cumulative impact on forest degradation remains a significant challenge. In this study, we combined multispectral data from Landsat sensors with hyperspectral data from the Earth Observing-One (Hyperion/EO-1) sensor to evaluate the efficacy of multiple vegetation indices in detecting forest responses to disturbances in an experimentally burned forest in southeastern Amazonia. Our experimental area was adjacent to an agricultural field and consisted of three 50-ha treatments – an unburned Control, a plot burned every three years, and a plot burned annually from 2004 to 2010. All plots were monitored to assess vegetation recovery after fire disturbance. These areas were also affected by three drought events (2007, 2010, and 2016) over the study period. We evaluated a total of 18 Vegetation Indices (VI), one unique to Landsat, 12 unique to Hyperion/EO-1, and five commons to both satellites (i.e., 6 total from Landsat and 17 from Hyperion). We used linear models (LM) to evaluate how changes in ground observations of forest structure (biomass, leaf area index [LAI], and litter production) associated with fire were captured by the two VIs most sensitive to forest degradation. Our results indicate that the Plant Senescence Reflectance Index (PSRI) derived from Hyperion/EO-1 was the most sensitive to vegetation changes associated with forest fires, increasing by 94% in burned vs. unburned forests. Of the Landsat-derived VIs, we found that the Green-Red Normalized Difference (GRND) were the most sensitive to forest degradation by fire, showing a marked decline (87%) in the burned plots compared with the unburned Control. However, compared to PSRI, the GRND was a better predictor of changes associated with fire, both in the forest interior or forest edge, for the three ground variables: biomass stocks (r2 = 0.5–0.8), LAI (r2 = 0.8–0.9), and litter production (r2 = 0.4–0.7). This study demonstrate that VIs can detect forest responses to fire and other disturbances over time, highlighting the relative strengths of each VI. In doing so, it shows how the integration of multispectral and hyperspectral data can be useful for monitoring tropical forest degradation and recovery. Moreover, it provides valuable insights into the limitations of existing approaches, which can inform the design of next-generation sensors for global forest monitoring.

The genetically programmed rhythmic alteration of diurnal gene expression in the aged Arabidopsis leaves.

The circadian clock regulates the daily pattern of temporal gene expression. In Arabidopsis, aging is associated with a shortening of the endogenous period of circadian rhythms under circadian conditions. However, the functional link between the circadian clock and aging under diurnal conditions and its physiological relevance remain elusive. In this study, we investigate and characterize the effect of aging on the waveforms of rhythmic gene expression patterns under light/dark cycles. Our analysis revealed that the diurnal rhythmic patterns of core clock genes undergo significant rhythmic alteration with phase shift and change of waveforms in aged plants compared to younger plants. Transcriptomic analysis indicated that this age-dependent rhythmic alteration occurs not only in core clock genes but also globally. Due to the rhythmic alteration patterns of the diurnal rhythmic gene expression, aged plants experience subjectively a shorter day and longer night. We also observed that genetic mutants of core clock component genes exhibited broadly yet distinctively altered changes in diurnal rhythmic gene expression patterns as aging progresses. Collectively, our findings support that age-dependent rhythmic alteration of diurnal gene expression rhythms reprograms the timetable of daily gene expression, leading to the physiological changes required for plant senescence.

Evaluation of morpho-cellular and spectroscopic characteristics of Myristica fragrans Houtt mace across three different maturation stages (juvenile, raw and ripe)

This study was based on comprehensive analysis of Myristica fragrans Houtt mace samples across various stages of maturation (juvenile, raw and ripe). The anatomical analysis was performed using SEM coupled EDX spectroscopy that revealed distinct cellular changes and the presence of oil-storage structures in the mace. The EDX analysis further confirmed the presence of key elements such as carbon (C), oxygen (O) and potassium (K) which contribute to mace's pharmacological properties. Spectrophotometric analysis revealed a steady increase in chlorophyll content as the mace matures, with total chlorophyll content rising from 1.02 during the juvenile stage to 1.25 at the raw stage and reaching 3.29 at the ripe stage. The Plant Senescence Reflectance Index (PSRI) shows a rise in carotenoid content, increasing from 0.15 in the juvenile stage to 0.17 at the raw stage and reaching 0.82 at the ripe stage. This increase correlates with the mace's colour transformation to crimson red during ripening. The FTIR spectroscopy analysis provided a detailed chemical characterization of the mace, identified various functional groups (carboxylic acid, aldehyde, alkanes, azides) and organic molecules. The presence of multiple functional groups across the maturation stages suggested a complex composition that likely contributes to the mace's sensory and pharmacological qualities.

SCOOP10 and SCOOP12 peptides act through MIK2 receptor-like kinase to antagonistically regulate Arabidopsis leaf senescence

Leaf senescence plays a critical role in a plant’s overall reproductive success due to its involvement in nutrient remobilization and allocation. However, our current understanding of the molecular mechanisms controlling leaf senescence remains limited. In this study, we show that the receptor-like kinase MALE DISCOVERER 1-INTERACTING RECEPTOR-LIKE KINASE 2 (MIK2) functions as a negative regulator of leaf senescence. We found that the SERINE-RICH ENDOGENOUS PEPTIDE 12, previously known to physically interact with MIK2, competes with SCOOP10 to regulate MIK2-dependent leaf senescence. We observed that increased expression of SCOOP10 or the application of exogenous SCOOP10 peptides accelerated leaf senescence in a MIK2-dependent manner. Conversely, SCOOP12 acted as a suppressor of MIK2-dependent leaf senescence regulation. Biochemical assays showed that SCOOP12 enhances while SCOOP10 diminishes MIK2 phosphorylation. Thus, the SCOOP12-MIK2 module might function antagonistically on SCOOP10-MIK2 signaling at late senescing stages, allowing for fine-tuned modulation of the leaf senescence process. Our study sheds light on the complex mechanisms underlying leaf senescence and provides valuable insights into the interplay between receptors, peptides, and the regulation of plant senescence.

Evapotranspiration measurements in pasture, crops, and native Brazilian Cerrado based on UAV-borne multispectral sensor.

In Brazil, agriculture consumes most of the available freshwater, especially in the Cerrado biome, where the rain cycle is marked by long periods of drought. This study, conducted at the Brazilian Agricultural Research Corporation (Embrapa) Research Corporation unit in Santo Antônio de Goiás, Goiás, Brazil, estimated evapotranspiration (ET) in different crops and soil cover. Using multispectral unmanned aerial vehicle (UAV) images, Sentinel satellite data, weather station information, and towers employing the eddy covariance method, we applied the "Simple Algorithm for Evapotranspiration Retrieving" (SAFER) to calculate ET in common bean, pasture, and semideciduous seasonal forest areas. The results showed a good agreement between UAV and satellite data, with R2 = 0.84, also validated with flow towers by the eddy covariance method. UAV-based ET was observed to correspond well to tower (EC) during full vegetative development of beans but is underestimated at the beginning of planting and in the final periods of plant senescence, due to the influence of soil or straw cover. These findings contribute to a better understanding of water dynamics in the system and to enhancing sustainable agricultural practices. This method, adapted for multispectral aerial imaging, can be applied flexibly and on-demand, in different contexts and ground cover. The study highlights the importance of integrated agricultural practices for better management of water resources and preservation of the Cerrado in balance with cultivation areas.

The H2S-responsive transcription factor ERF.D3 regulates tomato abscisic acid metabolism, leaf senescence, and fruit ripening.

Hydrogen sulfide (H2S) is a signaling molecule that regulates plant senescence. In this study, we found that H2S delays dark-induced senescence in tomato (Solanum lycopersicum) leaves. Transcriptome and RT-qPCR analyses revealed an Ethylene Response Factor ERF.D3 is quickly induced by H2S. H2S also persulfidated ERF.D3 at amino acid residues C115 and C118. CRISPR/Cas9-mediated gene editing and gene overexpression analyses showed that ERF.D3 negatively regulates leaf senescence and fruit ripening. Abscisic acid (ABA) levels were reduced by ERF.D3 overexpression, suggesting ERF.D3 might regulate ABA metabolism. Additionally, the abscisic acid 8'-hydroxylase-encoding gene CYP707A2, which is required for ABA degradation, was identified as an ERF.D3 target gene through transcriptome data, RT-qPCR, dual-luciferase reporter assays and electrophoretic mobility shift assays. ERF.D3 persulfidation enhanced its transcriptional activity towards CYP707A2. Moreover, the E3 ligase RNF217 ubiquitinated ERF.D3, which may accelerate fruit ripening during the late stage of fruit development. Overall, our study provides valuable insights into the roles of a H2S-responsive ERF.D3 and its persulfidation state in delaying leaf senescence and fruit ripening and provides a link between H2S and ABA degradation.

Contrasting Alleles of OsNRT1.1b Fostering Potential in Improving Nitrogen Use Efficiency in Rice.

Nitrogen use efficiency (NUE) is important for the growth and development of rice and is significant in reducing the costs of rice production. OsNRT1.1b is involved in nitrate assimilation, and the alleles at position 21,759,092 on chromosome 10 clearly separate indica (Pathum Thani 1 (PTT1) and Homcholasit (HCS)) and japonica (Azucena and Leum Pua (LP)) rice varieties. Rice morphological and physiological traits were collected at three nitrogen levels (N0 = 0 kg ha-1, N7 = 43.75 kg ha-1, and N14 = 87.5 kg ha-1). Leaf and tiller numbers in PTT1 and HCS at N7 and N14 were two to three times higher than those at N0. At harvest, the biomass yield in PTT1 was the highest, while the total grain number in HCS was the maximum. The leaf widths and total chlorophyll contents (SPAD units) of Azucena and LP increased with nitrogen application as well as photosynthetic pigment parameters; for example, plant senescence reflectance indices (PSRIs), structure-insensitive pigment indices (SIPIs), and modified chlorophyll absorption ratio indices (MCARIs) were highly related in the japonica varieties. PTT1 and HCS, both carrying the A allele at OsNRT1.1b, had better NUE than Azucena and LP with the G allele. HCS, overall, had better NUE than PTT1. The translation to grain yield of assimilates was remarkable in PTT1 and HCS compared with Azucena and LP. In addition, HCS converted biomass for a 75% higher yield than PTT1. The ability of HCS to produce high yields was achieved even at N7 nitrogen fertilization, manifesting efficient use of nitrogen.

Minimal assay detects population-level senescence in the aquatic plant <i>Lemna minor</i>

At the population level, senescence occurs when older individuals have increased risk of death and reduced reproduction compared to younger individuals. We investigated senescence in the aquatic plant <i>Lemna minor</i> (common duckweed), an important species for plant senescence research. Our objectives were to (1) confirm or refute the presence of population-level senescence in this model species; (2) develop a minimal assay of senescence requiring only once-weekly data collection; and (3) test whether there were appreciable differences in senescence in plants grown in glass compared to polystyrene petri dishes, with an aim to reducing single-use plastic waste and long-term research materials costs. We found that weekly survival arced downward with age when viewed on a semi-log plot, and weekly production of descendants decreased with age, with both findings indicating population-level senescence that matched previous work using more frequent data-collection (per Objectives 1 and 2). Additionally, we found no noteworthy differences in senescence between plants grown in glass versus polystyrene petri dishes (per Objective 3). The use of weekly data collection could liberate personnel resources for other research-group functions, and could make the <i>Lemna</i> system suitable for senescence- or demography-education exercises. The use of glass dishes could reduce lab waste and expense.

OsCNGC7 modulates calcium dynamics and accelerates leaf senescence in rice

Calcium plays a crucial role in regulating plant senescence. However, the specific effects of increased intranuclear calcium versus cytoplasmic calcium on aging remain unclear. Cyclic nucleotide-gated channels (CNGCs), which manage Ca2⁺ levels in plant cells, are particularly significant in this context. These channels are known to relocate between the nuclear envelope and the plasma membrane in response to stress and developmental signals. Through this movement, CNGCs help regulate the balance of cytosolic and intranuclear Ca2⁺. In this study, we categorized the 16 CNGC genes in rice into five subgroups. OsCNGCs are notably expressed in leaves, especially during the reproductive stage. Both OsCNGC6 and OsCNGC7 exhibit dual localization to the plasma membrane and the nuclear envelope. Knockdown of OsCNGC7 led to reduced levels of Ca2⁺ and K⁺ in plants. Conversely, yeast expressing the OsCNGC7 gene showed increased sensitivity to Ca2⁺. Additionally, while the [Ca2⁺]cyt was maintained at relatively low levels in both wild-type and OsCNGC7-RNAi lines, the fluorescence intensity was significantly higher in OsCNGC7-overexpressing lines, particularly in the nucleus of root tips. Overexpression of OsCNGC7 resulted in enhanced stomatal opening and accelerated leaf senescence from the tillering stage to grain filling in rice. Treatment with MeJA rapidly induced OsCNGC7 expression, while knockdown of OsCNGC7 delayed both MeJA-induced and dark-induced leaf senescence. Further analysis revealed that OsCNGC7 interacts with OsKAT2 and OsALMT2. In conclusion, our findings highlight the distinct roles of OsCNGCs in regulating senescence. This knowledge could provide new strategies for manipulating plant senescence and enhancing crop productivity.

Biogas slurry: A potential substance that synergistically enhances rapeseed yield and lodging resistance

Biogas slurry (BS) plays a vital role in improving the efficiency of crop production. On the flip side, the impact of BS on plant lodging factors and yield related traits is still obscure. Hence, we aimed to study the effects of pig and cow BS applications on yield formation, morpho-anatomical, mechanical, physiological properties and transcript expression patterns. The results showed that the yield and lodging resistance of rapeseed were synergistically improved via applying full BS dosage versus nitrogen fertilizer (CK). In addition, the seed yield was significantly increased by 23.9 % by promoting the dry matter accumulation and transport-ability, increasing number of pods by 8.4 % and 1000-seed weight by 5.1 %, respectively. Moreover, BS developed the stem mechanical strength by decreasing lodging index by 34.2 %, which was manifested by an increase in stem thickness and stiffness and a reduction in plant height. Besides, it enhanced the photosynthesis through promoting chlorophyll synthesis, delaying plant senescence, and accumulating N and K concentration. Anatomical observations revealed that BS increased greater number and area of stem vascular bundles, vessels, and maintained a dense microstructure than CK. Also, it boosted pectin, Ca2+ and K+ contents, which were significantly positively correlated with stem mechanical strength and reduced cellulose, lignin and hemicellulose contents. Meanwhile, correlation and structural equation modeling analysis validated the above results. Additionally, the differentially expressed genes were enriched in cell wall formation pathway, especially about the biosynthesis of pectin (PME, PG and PL), cellulose (CesA and CSL), lignin (PAL, POD, CCR, LAC and COMT) and hemicellulose (XTH and Xyl) were identified under BS. The above-mentioned results indicated that BS simultaneously affected lodging behavior by altering structural carbohydrates and modified yield composition by regulating dry-matter accumulation and allocation. This is the first comprehensive strategy on synchronizing rapeseed yield increase and lodging resistance under optimized BS management.

Osmanthus fragrans Ethylene Response Factor OfERF1-3 Delays Petal Senescence and Is Involved in the Regulation of ABA Signaling

Osmanthus fragrans is widely used in gardening, but the short flowering period of O. fragrans affects its ornamental and economic value. ERF, as a plant ethylene response factor, is an important link in the regulation of plant senescence. In this study, we conducted a comprehensive analysis of the functional role of OfERF1-3 within the petals of O. fragrans. Specifically, the OfERF1-3 gene was cloned and subjected to rigorous sequence analysis. Subsequently, to evaluate its expression patterns and effects, gene overexpression experiments were carried out on both Nicotiana tabacum and O. fragrans. The results showed that OfERF1-3-overexpressing tobacco plants exhibited longer petal opening times compared with those of wild plants. Measurements of physiological parameters also showed that the flowers of overexpressed tobacco plants contained lower levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) than those of the wild type. There was a lower expression of senescence marker genes in overexpressed tobacco and O. fragrans. A yeast two-hybrid assay showed that OfERF1-3 interacted with OfSKIP14 in a manner related to the regulation of ABA. In summary, OfERF1-3 can play a delaying role in the petal senescence process in O. fragrans, and it interacts with OfSKIP14 to indirectly affect petal senescence by regulating the ABA pathway.

PRL1 interacts with and stabilizes RPA2A to regulate carbon deprivation-induced senescence in Arabidopsis.

Leaf senescence is a developmental program regulated by both endogenous and environmental cues. Abiotic stresses such as nutrient deprivation can induce premature leaf senescence, which profoundly impacts plant growth and crop yield. However, the molecular mechanisms underlying stress-induced senescence are not fully understood. In this work, employing a carbon deprivation (C-deprivation)-induced senescence assay in Arabidopsis seedlings, we identified PLEIOTROPIC REGULATORY LOCUS 1 (PRL1), a component of the NineTeen Complex, as a negative regulator of C-deprivation-induced senescence. Furthermore, we demonstrated that PRL1 directly interacts with the RPA2A subunit of the single-stranded DNA-binding Replication Protein A (RPA) complex. Consistently, the loss of RPA2A leads to premature senescence, while increased expression of RPA2A inhibits senescence. Moreover, overexpression of RPA2A reverses the accelerated senescence in prl1 mutants, and the interaction with PRL1 stabilizes RPA2A under C-deprivation. In summary, our findings reveal the involvement of the PRL1-RPA2A functional module in C-deprivation-induced plant senescence.

Arabidopsis apoplast TET8 positively correlates to leaf senescence, and tet3tet8 double mutants are delayed in leaf senescence.

Extracellular vesicles (EVs) are membrane-bound exosomes secreted into the apoplast. Two distinct populations of EVs have been described in Arabidopsis: PEN1-associated and TET8-associated. We previously noted early leaf senescence in the pen1 single and pen1pen3 double mutant. Both PEN1 and PEN3 are abundant in EV proteomes suggesting that EVs might regulate leaf senescence in soil-grown plants. We observed that TET8 is more abundant in the apoplast of early senescing pen1 and pen1pen3 mutant rosettes and in older wild-type (WT) rosettes. The increase in apoplast TET8 in the pen1 mutant did not correspond to increased TET8 mRNA levels. In addition, apoplast TET8 was more abundant in the early leaf senescence myb59 mutant, meaning the increase in apoplast TET8 protein during leaf senescence is not dependent on pen1 or pen3. Genetic analysis showed a significant delay in leaf senescence in tet3tet8 double mutants after 6weeks of growth suggesting that these two tetraspanin paralogs operate additively and are positive regulators of leaf senescence. This is opposite of the effect of pen1 and pen1pen3 mutants that show early senescence and suggest PEN1 to be a negative regulator of leaf senescence. Our work provides initial support that apoplast-localized TET8 in combination with TET3 positively regulates age-related leaf senescence in soil-grown Arabidopsis plants.