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PubMed2025

UAV-based multispectral image analysis revealed stay-green haplotypes in wheat specific for different soil nitrogen levels.

BACKGROUND: The so-called stay-green trait, a delay in onset and progression of leaf senescence, is associated with slower chlorophyll degradation and higher photosynthesis rates during maturation resulting in higher crop yields. Understanding the genetic and physiological basis of the stay-green trait and breeding cultivars with stable stay-green behaviour across a range of different nitrogen (N) conditions and specifically under low N availability can contribute to ensuring wheat yields and reducing N fertilizer application. The goal of this study was therefore to identify haplotypes associated with high stay-green capacity under different N availability conditions in wheat. A diverse set of 221 wheat cultivars was grown under three different N levels and phenotyped by uncrewed aerial vehicle (UAV)-based multispectral imaging to characterise genetic and environmental variation in stay-green. Haplotypes associated with stay-green were identified across N levels and specifically under low N availability. RESULTS: The plant senescence reflectance index (PSRI) calculated from multispectral images was identified as the most specific stay-green indicator allowing for differentiation of genotypic effects due to its greater sensitivity to senescence-related changes in pigment composition and its higher reliability. We found genetic variance for stay-green and a consistent genetic correlation between stay-green and grain yield at all imaging dates and N levels within the utilised diversity panel confirming its potential as a future breeding target. Haplotype analyses revealed two favourable major allele haplotypes present in 95% of the stay-green cultivars, i.e. the top 25% of the diversity set based on PSRI values, which significantly enhance stay-green performance and grain yield. In addition, we identified a favourable minor allele haplotype specifically associated with stay-green under low N availability and capable of further increasing stay-green and grain yield when stacked onto the two favourable major allele haplotypes. CONCLUSIONS: The newly identified stay-green haplotypes can be further used for fine-mapping and identifying the underlying genes as well as for selecting for higher stay-green and grain yield. Thereby our results can contribute to improving our understanding of the complex genetic regulation underlying stay-green in different environments and to breeding new cultivars with stable performance across N levels or specifically under low N availability.

Triticum↗

PubMed2026

Methylation histology reveals the molecular mechanism by which red light-mediated DNA methylation delays leaf senescence in pak choi (Brassica rapa subsp. chinensis).

Leaf senescence is a key factor affecting the postharvest quality and shelf life of vegetables. The specific mechanisms by which light environment and DNA methylation mediate leaf senescence remain unclear. This study explored the molecular mechanism by which red light (RL) LED delays leaf senescence through DNA methylation in pak choi (Brassica rapa subsp. chinensis). In this study, RL treatment significantly suppressed leaf senescence in pak choi during postharvest storage and downregulated the expression of senescence-associated genes (SAGs). Experiments with methylation inhibitors confirmed its association with DNA methylation. Furthermore, whole-genome bisulfite sequencing revealed that during storage-induced senescence, pak choi exhibited significantly reduced methylation levels across its genome, particularly in promoter regions, and RL treatment reversed this effect. Furthermore, virus-induced gene silencing and overexpression experiments confirmed the central role of the demethylase BrDML3 (BraA01g004250.3.5C) in this process. Subsequently, a transcription factor under its regulation, BrNAC55 (BraA05g032630.3.5C), was identified and shown to promote leaf senescence by activating downstream SAGs (BrSGR1, BrPPH, BrSAUR36) to promote leaf senescence. In addition, this study found that BrNAC55 can also form a feedback loop with BrDML3, continuously amplifying leaf senescence. This study elucidates the mechanism by which RL-mediated DNA methylation delays leaf senescence, providing a foundation for postharvest preservation technologies.

DNA Methylation↗

PubMed2025

Comprehensive analysis of DNA methylome and transcriptome reveals the epigenetic regulation of nitric oxide treatment in delaying apricot fruit senescence.

Apricot produces climacteric fruit, which are perishable after harvest. To elucidate the regulatory role of NO treatment through DNA methylation in post-harvest senescence, apricot fruits were treated with 0.2 mmol/L sodium nitroprusside (SNP) solution for 10 min, with distilled water treatment serving as the control. Treated fruits were then stored at 25°C and 80% relative humidity. Changes in appearance quality, physiological parameters, metabolome profiles, transcriptome dynamics, and DNA methylation patterns were analyzed before and after storage. Results showed that NO treatment delayed apricot softening, increased flavonoid metabolite accumulation, and reduced lipid and abscisic acid accumulation, with these effects correlated to the expression of specific genes and transcription factors. This work reveals the epigenetic regulatory mechanism underlying NO treatment delaying ripening and senescence. Further analysis revealed that the transcription levels of ACO, PAL, UFGT-like, NCED1, PP2C, MYB21, CCoAOMT-like, CYP707A, and ZNF7-like were all correlated with DNA methylation. This indicates that SNP treatment can lead to large changes in DNA methylation levels in apricot fruits, and that the differences in gene transcription levels are associated with the occurrence of hypomethylation and hypermethylation. Collectively, these findings establish an epigenetic framework for post-harvest regulation of apricot fruit, revealing DNA methylation-mediated freshness preservation mechanisms.

DNA Methylation↗

PubMed2026

Disruption of the ubiquitin-mediated proteolysis pathway: a study of seed aging in Saposhnikovia divaricata caused by UBC1 gene family suppression.

BACKGROUND: Saposhnikovia divaricata (Turcz.) Schischk. is a perennial herb whose seed aging during storage significantly reduces germination rates, limiting industrial-scale production. Reactive oxygen species (ROS)-induced oxidative damage is a key driver of seed aging, but the underlying mechanisms in Saposhnikovia divaricata remain unclear. RESULTS: Suppression of the UBC1 gene family reduces the activity of ubiquitin-conjugating enzymes, leading to dysfunction of the ubiquitin-mediated proteolysis pathway, which in turn decreases protein degradation efficiency and causes the accumulation of damaged proteins. Transcriptome analysis revealed predominant downregulation of genes crucial for seed physiological maintenance. By the fourth year of storage, germination dropped sharply to 30.67%, accompanied by embryo cavitation. Downregulation of ribosome pathway genes hindered ribosome assembly and protein synthesis, while suppression of endoplasmic reticulum protein processing genes led to unfolded/misfolded protein accumulation and intensified cellular stress, accelerating aging. Proteomic analysis showed increased total differential and antioxidant-related proteins. ROS content fluctuated with storage time: peroxyl radicals peaked in year two (5.68 RFU/mg), whereas hydroxyl radicals and hydrogen peroxide were highest in year four (0.0655 pg/mL and 0.0946 pg/mL, respectively), with significant differences across periods. Elevated membrane-related proteins, increased electrical conductivity, and malondialdehyde content (maximum 54.30 nmol/g at year four) confirmed oxidative membrane damage. ROS-induced stress promotes protein misfolding, and reduced UBC1 expression is associated with impaired clearance of misfolded proteins by the ubiquitin-mediated proteolysis pathway. CONCLUSIONS: This study provides the first integrated transcriptomic and proteomic insight into UBC1 deficiency-mediated seed aging in Saposhnikovia divaricata. The findings enhance molecular understanding of seed aging and offer new directions for improving seed storage and viability.

Ubiquitin-Conjugating Enzymes↗

PubMed2025

The small nucleolar RNA NON-CODING RNA 1 negatively regulates drought tolerance in Arabidopsis thaliana.

Small nucleolar RNAs (snoRNAs) function in ribosome biogenesis, and many ribosome biogenesis-related genes were downregulated by osmotic stress, implying a negative role of snoRNAs in drought tolerance. A snoRNA, namely, the NON-CODING RNA 1 (NCR1) was studied for its roles in drought tolerance in Arabidopsis. In comparison with wild-type (WT) plants, the loss-of-function ncr1 mutant plants showed enhanced drought tolerance, which was restored in the NCR1-complemented plants, whereas the NCR1-overexpressing plants revealed a drought-sensitive phenotype. Physiological analyses revealed that the ncr1 plants had a higher leaf surface temperature, lower water loss rates, and improved cell membrane integrity compared with WT. Comparative leaf transcriptomics and proteomics suggested that wax biosynthesis, anthocyanin metabolism, and leaf senescence processes are regulated by NCR1 under both normal and water-deficit conditions. Under drought, an increase in wax and anthocyanin accumulations and a delay in leaf senescence in ncr1 plants, when compared with WT, supported the transcriptome and proteomics data. Additionally, the ncr1 plants exhibited higher abscisic acid (ABA) sensitivity and longer root hairs than WT. Collectively, our results suggest that NCR1 negatively regulates drought tolerance through modification of wax biosynthesis, anthocyanin accumulation, leaf senescence, cell membrane integrity, ABA responses, and root hair development.

Arabidopsis↗

PubMed2026

TGA6 directly activates ABF2 and ABF3 to promote leaf senescence in Arabidopsis thaliana.

Leaf senescence is a tightly regulated developmental process governed by a complex transcriptional network. Although the TGACG motif-binding (TGA) family of basic leucine zipper (bZIP) transcription factors are well-characterized regulators of plant defense responses, their roles in leaf senescence remain poorly understood. Here, we report that overexpression of TGA6 in Arabidopsis thaliana promotes early leaf senescence. Independent TGA6-overexpressing lines displayed premature leaf yellowing and significantly lower chlorophyll levels than wild-type (WT) plants under both normal growth and dark-induced senescence conditions. At the molecular level, RT-qPCR analysis revealed significant upregulation of canonical senescence marker genes, including NYC1, PAO, SAG12, SAG13, SGR1, and SGR2, in the TGA6-OE lines relative to WT plants. Furthermore, we found that the transcript levels of ABA-responsive element binding factor 2 (ABF2) and ABF3, which act upstream of these senescence markers, were significantly elevated in the TGA6-OE lines. Dual-luciferase reporter assays and electrophoretic mobility shift assay demonstrated that TGA6 directly binds to the TGACG motifs within the promoters of ABF2 and ABF3 to activate their transcription. Collectively, these findings demonstrate that TGA6 functions as a positive regulator of leaf senescence.

Arabidopsis↗

PubMed2026

Small nucleolar RNA HIDDEN TREASURE 2 reduces drought tolerance via multiple pathways in Arabidopsis.

Small nucleolar RNAs (snoRNAs) contribute to ribosome biogenesis and modulate various aspects of plant growth and development. Given that osmotic stress downregulates numerous genes associated with ribosome biogenesis in roots, we hypothesize that snoRNAs might function in modulating plant responses to osmotic and drought stresses. To prove this hypothesis, we assessed the role of a C/D-box snoRNA, namely the HIDDEN TREASURE 2 (HID2), in Arabidopsis thaliana responses to drought using both loss-of-function and overexpression approaches. Under drought conditions, the Arabidopsis hid2 mutant displayed a significantly higher survival rate than both wild-type (WT) and HID2-complemented plants, while HID2-overexpressing plants showed a lower survival rate than WT. A series of physiological assays indicated that the hid2 mutant maintained a slower rate of water loss and more intact cell membranes than WT plants under drought, which supported their drought-tolerant phenotype. Comparative leaf transcriptome and proteome analyses revealed that processes related to wax biosynthesis, senescence, and anthocyanin accumulation were differentially regulated between hid2 and WT plants under water-deficit conditions. Consistently, the hid2 mutant accumulated higher amounts of wax and anthocyanins and exhibited delayed leaf senescence relative to WT plants under drought. Additionally, the hid2 mutant showed improved ability to increase sensitivity to abscisic acid (ABA), scavenge reactive oxygen species (ROS), and extended root hairs. Overall, these findings demonstrate HID2's role as a negative modulator in Arabidopsis drought tolerance by negatively affecting cell membrane stability, wax and anthocyanin biosynthesis, senescence, ROS-scavenging capacity, ABA responsiveness, and root hair formation.

Arabidopsis↗

PubMed2025

A major trade-off between growth and defense in Arabidopsis thaliana can vanish in field conditions.

When wild plants defend themselves from pathogens, this often comes with a trade-off: the same genes that protect a plant from disease can also reduce its growth and fecundity in the absence of pathogens. One protein implicated in a major growth-defense trade-off is ACCELERATED CELL DEATH 6 (ACD6), an ion channel that modulates salicylic acid (SA) synthesis to potentiate a wide range of defenses. Wild Arabidopsis thaliana populations maintain significant functional variation at the ACD6 locus, with some alleles making the protein hyperactive. In the greenhouse, plants with hyperactive ACD6 alleles are resistant to diverse pathogens, yet they are of smaller stature, their leaves senesce earlier, and they set fewer seeds compared to plants with the standard allele. We hypothesized that ACD6 hyperactivity would not only affect the growth of microbial pathogens but also more generally change leaf microbiome assembly. To test this in an ecologically meaningful context, we compared plants with hyperactive, standard, and defective ACD6 alleles in the same field-collected soil, both outdoors and in naturally lit and climate-controlled indoor conditions, taking advantage of near-isogenic lines as well as a natural accession and a CRISPR-edited derivative. We surveyed visual phenotypes, gene expression, hormone levels, seed production, and the microbiome in each environment. The genetic precision of CRISPR-edited plants allowed us to conclude that ACD6 genotype had no effect on mature field plants in our setting, despite reproducibly dramatic effects on greenhouse plants. We conclude that additional abiotic and/or microbial signals present outdoors-but not in the greenhouse-greatly modulate ACD6 activity. This raises the possibility that the fitness costs of other commonly studied immune system genes may be grossly misjudged without field studies.

Arabidopsis↗

PubMed2026

USP10-SIRT6-PARP1 axis drives keratinocyte senescence and skin photoaging under chronic UVA exposure.

Chronic exposure to ultraviolet A (UVA) radiation is the principal environmental driver of skin photoaging, yet the upstream molecular events that commit irradiated keratinocytes to senescence remain poorly understood. Here we show that SIRT6, an NAD+-dependent protein deacetylase with established roles in genome maintenance and organismal longevity, functions as a central gatekeeper of keratinocyte homeostasis under photic stress. Using a chronic UVA irradiation model in mice together with cultured human keratinocytes, we demonstrate that UVA inflicts extensive DNA damage and G2/M cell-cycle arrest, accompanied by selective depletion of SIRT6 among all sirtuin family members. Mechanistically, UVA suppresses the deubiquitinase USP10 at both transcriptional and post-transcriptional levels, thereby licensing ubiquitin-dependent proteasomal degradation of SIRT6. The resulting SIRT6 deficiency unleashes hyperactivation of the DNA-damage sensor PARP1, amplifying genomic injury signaling and driving keratinocytes into irreversible senescence with concomitant elaboration of a broad pro-inflammatory secretory programme encompassing chemokines and cytokines. Pharmacological reactivation of SIRT6 with the selective agonist UBCS039 reverses epidermal hyperplasia, attenuates DNA damage and senescence marker accumulation, and suppresses inflammatory mediator induction both in vivo and in vitro, establishing SIRT6 loss as a causal rather than correlative event. Furthermore, molecular docking and functional validation identify osthole, a plant-derived coumarin from the medicinal herb Cnidium monnieri, as a candidate SIRT6-engaging compound that counteracts UVA-induced senescence and inflammation in keratinocytes. Collectively, these findings define a USP10-SIRT6-PARP1 signaling axis whose disruption underlies cutaneous photoaging and suggest that SIRT6-directed strategies may offer therapeutic benefit against UV-driven tissue degeneration.

Animals↗

PubMed2026

Turnip mosaic virus alters phosphorus metabolism and shoot-root allocation without resource competition.

Plant viruses affect production through symptom induction in host plants. These symptoms could partially arise from nutrient deprivation: The resource competition hypothesis posits that massive viral replication deprives hosts of essential nutrients, yet direct evidence for phosphorus (P) competition is lacking. Moreover, it is reported that biotic stresses can lead to alterations on P metabolism. Using a hydroponic system enabling separate analysis of shoots and roots in adult Arabidopsis thaliana plants, we investigated whether Turnip mosaic virus (TuMV) drawed significant P internal pools leading to P competition or altered P metabolism. TuMV genomic RNA represented < 0.3% of the P pool allocated to 18S rRNA, refuting the resource competition hypothesis. Instead, TuMV induced a marked shoot-to-root P redistribution: Shoot/Root Pi and Porg changed from 1.7 to 1.04 to 0.71 and 0.68, respectively. This altered partitioning correlated with organ-specific gene expression changes: high-affinity transporters PHT1; 4 and PHT1; 5 were co-induced in shoots, whereas immunity-related PHT1; 4 was uniquely repressed in roots. The senescence-associated gene SEN1 showed opposite regulation between organs (repressed in shoots, induced in roots), distinguishing virus-induced responses from canonical senescence. Multivariate analysis revealed that shoots and roots only partially share physiological and molecular responses to TuMV. The virus reprograms phosphorus metabolism through organ-specific changes, not through resource depletion, and roots act as a distinct hub integrating infection response, senescence, and nutrient dynamics. This study advances the understanding of growth-defense trade-offs in plant mineral nutrition and identifies new targets for maintaining crop productivity under biotic stress.

Arabidopsis↗

PubMed2026

Ubiquitin ligase HcPUB30 targets HcWRKY1 to regulate monoterpenoids synthesis in Hedychium coronarium.

Hedychium coronarium, a perennial herb belonging to the genus Hedychium Koenig within the family Zingiberaceae, is renowned for its pleasant fragrance. The volatile compounds of flowers are primarily terpenoids, which are catalyzed by terpenoid synthase (TPS). Earlier studies have shown that HcWRKY1 transcription factor can bind to the promoter of HcTPS1, regulating the metabolism of terpenoids. To further investigate the upstream molecular mechanisms that regulate the release of volatile compounds in Hedychium, we focused on a crucial U-box type of E3 ubiquitin ligase involved in regulating transcription factors. This study utilized genomic data to identify HcPUB gene family. In combination with transcriptome data, seven candidate HcPUB genes were identified and cloned with subsequent functional analysis. Yeast two-hybrid assay demonstrated that HcPUB30 was the sole interactor of HcWRKY1 among the seven HcPUB candidates. In vivo and in vitro ubiquitination assays demonstrated that HcPUB30 ubiquitinates and promotes the degradation of HcWRKY1 via the 26S proteasome pathway. Multi-alignment analysis revealed that HcPUB30 possesses a conserved U-box domain and ARM motifs, which are implicated in plant growth and development. Subcellular localization indicated that HcPUB30 is localized in both the nucleus and cytoplasm. Quantitative real-time PCR analysis revealed that HcPUB30 exhibited the highest expression in petal tissues, and its expression peaked during floral senescence stage. Virus-induced gene silencing of HcPUB30 in Hedychium petals resulted in a significant decrease in monoterpenoid content, accompanied by a significant reduction in the relative expression levels of HcWRKY1 and HcTPS1. These findings indicate that HcPUB30 participates in the regulation of monoterpenoid biosynthesis by mediating HcWRKY1 in Hedychium petals.

Plant Proteins↗

PubMed2025

Tonoplast sucrose transporter SUT4-dependent sugar partitioning modulates phenological transitions and reproductive success in poplar.

Climate uncertainty is intensifying the need for greater plasticity in carbohydrate reserve utilization to support winter survival and spring growth in woody perennials. In poplar, the single-copy SUT4, which encodes a tonoplast-localized sucrose transporter, and the SUT5/SUT6 genome duplicates, which encode plasma membrane-localized transporters, are expressed year-round, with SUT4 showing the highest expression during cool seasons. Given its role in vacuolar sucrose efflux and winter-predominant expression, SUT4 may play a key role in modulating seasonal carbohydrate dynamics. While SUT4-knockdown and knockout effects have been studied under greenhouse conditions, their impact under field conditions remains unexplored. Here, we report a field-based study comparing CRISPR knockout mutants of winter-expressed SUT4 and SUT5/SUT6 in Populus tremula × alba. We show that sut4, but not sut5/6, mutants exhibited earlier autumn leaf senescence, delayed spring bud flush, reduced stem growth, and altered sugar partitioning in winter xylem and bark relative to controls. After 2 years in the field, all genotypes flowered before leaf flush in early spring; however, sut4 mutants produced sterile ovules despite developing normal-looking catkins. Metabolic profiling revealed disrupted sucrose and raffinose dynamics in elongating sut4 catkins. This was accompanied by transcriptomic signatures of elevated stress and downregulation of proanthocyanidin biosynthesis and circadian clock genes. These findings highlight the critical role of SUT4 in coordinating sugar allocation, stress responses, and seasonal development in poplar.

Populus↗