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PubMed2026

Ultraviolet-B-induced OsKOL4 promotes ABA accumulation by inhibiting OsABA8ox1 and OsABA8ox2 expression.

Ultraviolet-B (UV-B) light is a component of sunlight that influences plant survival and adaptation. UV-B induces plants to regulate their phenotypes and metabolism to increase resistance to UV-B and associated stresses. Abscisic acid (ABA) metabolism and signaling are important for plant responses to UV-B. However, the mechanisms underlying UV-B-induced ABA accumulation and signaling in rice remain poorly understood. Here, we report that ENT-KAURENE OXIDASE LIKE 4 (OsKOL4) regulates UV-B-induced responses and ABA biosynthesis. UV-B activates OsKOL4 expression via OsbZIP48, an ELONGATED HYPOCOTYL 5 (HY5) homolog that directly binds to the OsKOL4 promoter. Rice plants overexpressing OsKOL4 exhibit UV-B-induced phenotypes under normal conditions, along with ABA overaccumulation phenotypes resulting from increased ABA levels. Moreover, UV-B promotes ABA accumulation by inhibiting the expression of the ABA 8'-HYDROXYLASE1 and ABA 8'-HYDROXYLASE 2 (OsABA8ox1/2) genes through OsKOL4. OsKOL4 interacts with the transcription factor AP2/ERF ON CHROMOSOME 3 (OsAPE3), which in turn represses the transcription of OsABA8ox1/2. Furthermore, both UV-B and OsKOL4 enhance the binding of OsAPE3 to the OsABA8ox1/2 promoters. Collectively, our findings demonstrate that the OsKOL4-OsAPE3 module regulates ABA homeostasis in response to UV-B signaling by reducing ABA catabolism.

Abscisic Acid↗

PubMed2026

Exogenous ABA enhances cold tolerance of Rhododendron yedoense var. poukhanense under subzero temperature: integrating physiology, transcriptome, and proteome.

Low temperature limits the growth and ornamental value of evergreen shrubs. Rhododendron yedoense var. poukhanense, an important ornamental shrub from Northeast China, frequently suffers freezing damage during winter. While exogenous abscisic acid (ABA) enhances cold tolerance in many plants, its molecular mechanisms at subzero temperatures remain poorly understood in non-model species lacking chromosome-level reference genomes. This study investigated the effects of exogenous ABA on freezing tolerance in R. yedoense var. poukhanense at -4 °C using an integrated physiological, transcriptomic, and proteomic approach. Cutting seedlings were subjected to four treatments: CK (22°C control), A (22°C + ABA), LT (-4°C), and ALT (-4°C + ABA). Photosynthetic pigments, osmotic regulation substances, antioxidant enzyme activities, and malondialdehyde (MDA) content were measured. Transcriptome sequencing and quantitative proteomics were performed, and transcriptome data were validated by quantitative real-time PCR (qRT-PCR) of 15 selected genes. ABA pretreatment reduced visible cold injury severity, partially preserved photosynthetic pigments, decreased MDA content by 28.7%, and promoted recovery of catalase (+43.6%), superoxide dismutase (+31.1%), and peroxidase (+20.0%) activities under freezing stress. Transcriptome analysis revealed 8, 444 differentially expressed genes (DEGs) in LT versus CK and 6, 481 DEGs in ALT versus CK, representing a 23% reduction in transcriptional reprogramming scope attributable to ABA priming. The ALT versus LT comparison identified only 1, 690 additional DEGs, indicating that most cold-responsive genes were pre-activated during the ABA priming phase. Proteome analysis identified 1, 461 differentially expressed proteins (DEPs) in ALT versus CK. Integrated analysis revealed extensive post-transcriptional regulation, with transcript-protein concordance of only 1.0-4.1%, and co-enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in both omics layers. qRT-PCR validation confirmed high reliability of the transcriptome data (R2 = 0.8500). These findings demonstrate that exogenous ABA enhances freezing tolerance through multi-layered molecular regulation encompassing transcriptional buffering, translational reprogramming, and functional reallocation from photosynthesis to stress protection. This study provides the first integrated physiology-transcriptome-proteome framework for ABA-mediated freezing tolerance in an evergreen ornamental shrub and offers theoretical support for ABA-based winter protection strategies.

Rhododendron yedoense var. Poukhanense↗

PubMed2026

OsICL-associated metabolic reprogramming during dehydration in rice is regulated by ABA and modulated by ACC and its metabolites.

Drought coordinates hormonal, transcriptional, and metabolic reprogramming, but how abscisic acid (ABA) and 1-aminocyclopropane-1-carboxylic acid (ACC) jointly shape cereal dehydration responses remains unclear. We integrated hormone profiling, transcriptome and promoter analyses, synthetic promoter assays, and metabolite profiling in rice. ABA and ACC contents increased markedly in rice shoots under moderate soil water deficit. Combined ABA + ACC treatment showed larger absolute overlaps with dehydration-responsive genes than either ABA or ACC treatment alone in shoots; in roots, this pattern was observed for induced but not repressed genes. Promoters of dehydration- and ABA-inducible genes were enriched in ACGT-core motifs, including a CGTACG core preferentially embedded in ACGTACGT, designated the eXtended ACGT box (Xbox). Multimerised Xbox conferred transcriptional induction under soil water deficit and in response to ABA. OsICL was induced under soil water deficit and by ABA or ACC; in shoots, combined ABA + ACC treatment produced the highest mean transcript accumulation. OsICL overexpression and knockout lines showed altered organic-acid, sugar, and amino-acid profiles, particularly under soil water deficit, but several metabolites changed in the same direction in both line classes. These findings support an ABA-centred, ACC-modulated model of dehydration-responsive transcription and associate OsICL regulation with broader, condition-dependent changes in primary metabolism.

Oryza sativa↗

PubMed2026

From activation to desensitization: How ABA balances plant growth and abiotic stress response?

Abscisic acid (ABA) signaling is a central regulator of plant adaptation to abiotic stress, dynamically coordinating stress responses with growth and development. Rapid activation of ABA signaling promotes plant survival during the early stages of stress, whereas prolonged stress requires timely attenuation of the pathway to restore growth and prevent excessive stress responses. Recent studies have uncovered diverse mechanisms underlying ABA desensitization, including regulation of SnRK2 kinases, phytohormone crosstalk, nutrient signaling, protein trafficking, post-translational modifications, and feedback regulatory networks. Together, these interconnected mechanisms enable plants to fine-tune ABA signaling in response to developmental and environmental cues. In this review, we summarize recent advances in understanding the molecular mechanisms that attenuate ABA signaling and restore the balance between growth and stress adaptation during prolonged stress. We also highlight outstanding questions and discuss strategies for engineering ABA signaling dynamics to improve crop resilience, productivity, and adaptation to increasingly variable environments.

Abscisic Acid↗

PubMed2026

Positive feedback loop between RAF12 and ABI5 reinforces ABA-mediated suppression of Arabidopsis seed germination.

ABA-INSENSITIVE 5 (ABI5) is a key transcriptional regulator mediating abscisic acid (ABA)-induced suppression of seed germination. However, the downstream regulatory network through which ABI5 exerts its function remains incompletely understood. Here, by integrating ChIP-seq and RNA-seq analyses, we identify RAF12, a member of the B2 Raf-like kinase subfamily, as a direct transcriptional target of ABI5. ABI5 binds to the RAF12 promoter and activates its expression. Loss-of-function raf12 mutants exhibit reduced sensitivity to ABA during seed germination, suggesting a negative regulatory role for RAF12 in this process. Conversely, RAF12 interacts with and phosphorylates ABI5, thereby enhancing its transcriptional activity. Further analysis showed that RAF12 regulates its own kinase activity through autophosphorylation. Mutations at its phosphorylation sites significantly weaken its ability to enhance ABI5's transcriptional activity. Together, these findings uncover a positive feedback loop wherein ABI5 transcriptionally activates RAF12, which in turn reinforces ABI5 activity through phosphorylation. This module may function in parallel with the canonical SnRK2s-ABI5-mediated ABA signaling cascade, offering new mechanistic insights into the fine-tuning of ABA responses during seed germination.

Arabidopsis↗

PubMed2026

Plant U-box E3 ligases: Versatile regulators of environmental stress adaptation and ABA signaling.

Ubiquitination is a reversible post-translational modification that orchestrates a wide spectrum of fundamental processes throughout the plant life cycle. Executed by a hierarchical E1-E2-E3 cascades, this modification tags targets with ubiquitin to modulate their turnover, activity, or subcellular compartmentalization. Among the diverse E3 ligase families, plant U-box (PUB) proteins stand out as a prominent class that determines substrate selection and has emerged as a focal point of stress biology. In this review, we first delineate the structural features of PUB proteins, highlighting their conserved domains and associated regulatory motifs. We then systematically dissect their multifaceted functions in abiotic stress adaptation, encompassing drought, salinity, extreme temperatures, oxidative stress, heavy metal toxicity, with particular emphasis on their integration with ABA signaling networks. We further outline critical knowledge gaps and propose future strategies to decode the regulatory architecture of PUBs. Collectively, this review provides a theoretical foundation and new insights for facilitating the genetic improvement of crop resilience in the face of continuously intensifying environmental stresses through the manipulation of PUB-mediated ubiquitination networks.

ABA signaling↗

PubMed2026

Genome-Wide Analysis of the PYL Gene Family and Its Expression Dynamics in Response to Abscisic Acid in Tomato.

The plant hormone abscisic acid (ABA) plays a crucial role throughout the plant life cycle and in adaptive responses to environmental stresses. The pyrabactin resistance 1-like (PYR/PYL/RCAR) proteins act as key regulators in the ABA signal transduction pathway by functioning as direct receptors for ABA. Although PYL genes have been identified in a variety of plant species, their evolutionary and structural characteristics in tomatoes (Solanum lycopersicum) remain elusive. To address this gap, we identified nine SlPYL genes, which were classified into three subfamilies: I (two genes), II (three genes), and III (four genes), and their encoded proteins were predicted to be primarily localized in the cytosol and chloroplast. Structural analysis revealed diverse exon-intron organizations along with five conserved motifs. All identified SlPYLs contained the START domain (PF10604), validating their identity as actual PYL proteins. Prediction of cis-acting regulatory elements in SlPYL's promoter regions was found to be associated with light responsiveness, hormone signaling, stress responses, and plant growth and development. Prediction of post-translational modification sites indicated that SlPYLs are predominantly phosphorylated and acetylated at serine and lysine residues, respectively. Tertiary structure modeling demonstrated conserved three-dimensional architectures among SlPYL proteins, supporting their functional conservation. Expression profiling revealed that specific SlPYL genes exhibit distinct expression patterns across different tissues (root, leaf, and bud) following ABA treatment, indicating functional diversification. Considering the well-established negative correlation between ABA accumulation and bud outgrowth, the ABA-induced differential expression (3~5-fold) of some SlPYL genes (SlPYL3, SlPYL4, SlPYL7, and SlPYL8), particularly in bud tissues after 24 hpt, suggests a potential role in ABA-mediated suppression of bud outgrowth. However, these functional inferences are primarily based on genome-wide computational analyses and expression profiling and therefore require further experimental validation.

Solanum lycopersicum↗

PubMed2026

Abscisic acid promotes RBOH-dependent reactive oxygen species production and lignin biosynthesis in pears via the PuABI5-PuMYB169 module.

Pear stone cell lignification, a critical determinant of fruit texture and quality, is regulated by developmental and environmental cues, with abscisic acid (ABA) playing a central role. However, the molecular mechanisms underlying its role in reactive oxygen species (ROS)-mediated lignification remain unclear. Here, we show that PuABI5, a key component in ABA signaling, directly combines with PuMYB169, the master regulator of stone cell lignification, to modulate ROS production and lignin biosynthesis in pear fruit. Exogenous application of ABA enhances H2O2 and lignin accumulation in both pear fruits and calli, and ABA-activated PuABI5 positively regulates stone cell lignification. We demonstrate that ABA-induced PuABI5 binds directly to the PuMYB169 promoter and activates its expression to promote the transcription of PuRBOHF and lignin-related genes, thereby enhancing ROS production and lignin accumulation. Notably, PuABI5 interacted with PuMYB169 to enhance the induction of PuRBOHF expression, leading to elevated levels of H2O2, which feedback to strengthen the interaction between PuABI5 and PuMYB169. Collectively, our findings elucidate that ABA induces ROS-mediated lignification of stone cells in pears by activating the PuABI5-PuMYB169 transcriptional module.

Lignin↗

PubMed2026

MhSHINE2-like interacts with MhGRF3 to promote drought tolerance via modulating stomatal aperture in apple.

Drought poses a significant global challenge to agriculture, substantially reducing crop yields. Abscisic acid (ABA) plays a crucial role in response to drought stress. Nevertheless, the molecular mechanism underlying the ABA-mediated drought stress response in apple remains poorly understood. We identified a drought- and ABA-induced AP2/ERF transcription factor (TF), MhSHINE2-like, which positively regulates drought stress tolerance in apple. Biochemical analysis showed that MhSHINE2-like directly binds to the GAGA-rich element in the promoter of the ABA biosynthesis gene MhNCED3, promoting its transcription under drought stress. Overexpression of MhNCED3 promotes ABA accumulation and enhances apple drought tolerance by regulating stomatal closure under drought stress. Further studies revealed that MhSHINE2-like physically interacts with 14-3-3 protein, MhGRF3, which also contributes positively to drought tolerance. Notably, MhSHINE2-like and MhGRF3 function cooperatively to modulate the expression of downstream genes, promoting ABA accumulation, and consequently enhancing drought tolerance in apple. These findings reveal a regulatory network mediated by the combined effects of TFs and chaperone proteins, offering valuable genetic resources for the development of drought-tolerant apple cultivars.

Malus↗

PubMed2025

A novel genus of virulent phage targeting Acinetobacter baumannii: Efficacy and safety in a murine model of pulmonary infection.

Acinetobacter baumannii is a notable opportunistic pathogen responsible for severe hospital-acquired infections, with multidrug-resistant strains posing significant treatment challenges. Phage therapy, which employs bacteriophages as natural bacterial antagonists, has gained renewed attention as a promising solution to combat antibiotic-resistant infections. In this study, we isolated and characterized a novel virulent phage, vB_AbaS_qsb1, which specifically lyses A.baumannii. Phylogenetic and genomic analyses indicate that vB_AbaS_qsb1 is the founding member of a previously unreported genus, which we propose to name Acinibactriovirus, with Acinibactriovirus lysinus as the type species. vB_AbaS_qsb1 demonstrated robust stability across diverse temperature and pH ranges, a short latent period, and no known virulence or antibiotic resistance genes within its 54,713 bp dsDNA genome. Safety assessments showed that high-dose vB_AbaS_qsb1 induced no adverse effects in mice, with histopathology confirming its safety profile. Therapeutic experiments further indicated that vB_AbaS_qsb1 provided at least 50% protection against A.baumannii-induced pneumonia, significantly reducing bacterial loads and inflammation markers, while maintaining high phage titers in lung tissue.This study introduces vB_AbaS_qsb1 as a promising candidate for phage therapy against A.baumannii, offering both innovative insights and a valuable framework for future isolation, genomic characterization, and efficacy evaluation of phages targeting antibiotic-resistant bacteria.

Animals↗

PubMed2026

Comparative transcriptomic and physiological analyses uncover key regulatory pathways associated with drought tolerance in wheat.

Drought severely limits wheat yield, yet its molecular basis remains incompletely understood. We compared a drought-tolerant line (A25) and a drought-sensitive line (A8) under water deficit across three developmental stages using physiological assays and transcriptomics. A25 exhibited stronger osmotic adjustment and antioxidant defense, with higher proline accumulation and enhanced activities of ascorbate peroxidase, catalase, and other ROS-scavenging enzymes. RNA-seq revealed distinct drought-responsive expression patterns, with differentially expressed genes enriched in MAPK signaling and ABA-dependent pathways. ABA-responsive genes were more abundant and strongly induced in A25, suggesting enhanced ABA signal transduction as a key mechanism. Weighted gene co-expression network analysis identified a drought-associated purple module positively correlated with physiological resistance, from which six hub genes (MAPKKK17, Avr9/Cf-9, RPPL1, RGA1, UBC28, AGPs5) were highlighted as potential regulators. Collectively, coordinated activation of ABA signaling and MAPK cascades, mediated by these hub genes, underlies the robust drought tolerance of A25, providing promising molecular targets for wheat breeding and improvement.

Triticum↗

PubMed2026

DNA hypermethylation of abscisic-acid-related genes helps enhance the cold tolerance of tetraploid rice.

Polyploid plants exhibit enhanced stress resistance and superior adaptability to extreme environments, but the underlying molecular mechanisms remain incompletely understood. Here we confirm that tetraploid rice exhibits stronger cold tolerance than diploid rice. This improved tolerance is mediated by reduced malondialdehyde accumulation, elevated antioxidant enzyme activity, and epigenetic regulation of genes involved in abscisic acid (ABA) biosynthesis and signaling. Under cold stress, tetraploid rice induces stress-responsive genes (especially in the ABA pathway) more rapidly and to higher levels than diploid rice. This enhanced gene expression coincides with increased endogenous ABA accumulation. Furthermore, polyploidization and cold stress synergistically induce high methylation at CG, CHG, and CHH sites in genes and transposons (TEs). Notably, the methylation level of class II TEs in tetraploid rice is significantly higher than in diploid rice under low temperatures. To suppress TE activation in gene promoter regions under cold stress, tetraploid rice enhances the methylation level of ABA pathway-related gene promoters, thereby silencing TEs and maintaining genome stability. Collectively, these results enrich the theoretical understanding of the strong stress tolerance in polyploid plants and provide theoretical support for breeding cold-tolerant polyploid rice varieties.

ABA↗

PubMed2026

CaMYB121-CaABF2 negative feedback loop modulates CaNHX2 expression to confer salt tolerance in pepper.

Salt stress is a major abiotic factor that severely restricts pepper (Capsicum annuum) production. Although abscisic acid (ABA) is vital for salt tolerance, the transcriptional regulatory networks governing ABA-mediated salt defense remain largely unknown. Here, we uncovered a negative feedback loop between CaMYB121 and CaABF2.1/2 that modulates the expression of CaNHX2.1/2/3, thereby enhancing salt tolerance in pepper plants. RNA-seq analysis revealed that CaMYB121 displayed an expression pattern consistent with that of CaNHX2 after salt treatment. Silencing CaMYB121 markedly reduced salt tolerance and inhibited root growth. Mechanistically, CaMYB121 directly binds to the CaNHX2 promoter to activate transcription, thereby promoting salt resilience. Salt stress also robustly triggered ABA signaling genes, with CaABF2.1/2 displaying expression patterns closely mirroring those of CaMYB121. Transient silencing of CaABF2.1/2 results in phenotypes similar to those observed with CaMYB121 suppression. Notably, CaMYB121 activates CaABF2.1/2 transcription by binding to its promoters, whereas CaABF2.1/2 represses CaMYB121 expression by directly targeting its promoter, forming a self-regulating feedback loop that prevents excessive defense activation. Collectively, our findings reveal a CaMYB121-CaABF2 feedback circuit that dynamically balances growth and defense to optimize salt tolerance in pepper plants.

Salt Tolerance↗

PubMed2026

Genome-wide identification of the superoxide dismutase gene family in Lycium barbarum and their expression profiles under abiotic stress and phytohormone treatment.

BACKGROUND: Superoxide dismutases (SODs) are crucial metalloenzymes that constitute the first line of defense against reactive oxygen species in plants under abiotic stress. Wolfberry (Lycium barbarum) is an economically important medicinal plant with notable stress tolerance, however, a comprehensive genome-wide analysis of its SOD gene family has not yet been performed. RESULTS: We identified ten wolfberry SOD genes (LbaSODs) and classified them into three subfamilies: iron-SODs (Fe-SODs), manganese-SODs (Mn-SODs), and copper/zinc-SODs (Cu/Zn-SODs). Members within each subfamily shared conserved gene structures and motifs. Segmental duplication was the primary driver of LbaSOD expansion, with three paralogous pairs identified. Analysis of cis-regulatory elements in the promoter region revealed a predominance of stress- and hormone-responsive cis-elements, particularly ABA-responsive elements (ABREs) (22 copies) and LTR (17 copies) motifs. Tissue-specific expression profiling revealed that LbaSOD2 and LbaSOD5 expression peaked during early fruit development, whereas LbaSOD6, LbaSOD9, and LbaSOD10 were progressively upregulated through fruit maturation. Under abiotic conditions, Fe-SOD members were markedly suppressed during prolonged drought, whereas LbaSOD9 and LbaSOD10 were rapidly induced in response to salt stress. Among the phytohormone treatments, methyl jasmonate (MeJA) elicited the most pronounced response, with LbaSOD5 expression increasing by approximately 60-fold after 24 hours. Notably, abscisic acid (ABA) triggered an exceptionally strong transcriptional induction of LbaSOD5 (2.5 × 105-fold), LbaSOD10 (6 × 105-fold), and LbaSOD6 (70-fold). In addition, LbaSOD3 and LbaSOD7 transcripts were undetectable in any of the tested conditions. CONCLUSIONS: This study provides the first comprehensive characterization of the LbaSOD gene family and elucidates its hormone- and stress-responsive regulatory landscape, providing a valuable foundation for future functional investigations of LbaSOD genes in abiotic stress adaptation. The extraordinarily strong ABA-mediated induction of specific LbaSOD members, together with their tissue- and stress-specific expression patterns, highlights their potential as targets for genetic improvement of stress tolerance in wolfberry.

Lycium barbarum↗

PubMed2026

Grafting and biodynamic nanosilica-induced physiological and transcriptomic modulation of chilli (Capsicum annuum L.) under drought stress.

Chilli (Capsicum annuum L.) is an economically important vegetable crop cultivated worldwide. Increasing drought stress associated with climate change has severely reduced chilli productivity. Although grafting and silicon-based nanomaterials have each been investigated independently as drought mitigation strategies in Solanaceae crops, this study represents, to our knowledge, the first investigation of their combined physiological, yield, and genome-wide transcriptomic effects in chilli under experimentally validated drought stress. Biodynamic nanosilica (BNS) is an α-quartz nanoparticle preparation (20-200 nm) derived from the biodynamic agricultural preparation BD501 through a vortex-triturating process, and distinct from chemically synthesised nanosilica in preparation method and surface bioavailability, applied as a foliar spray at 50 mg L-1. Five treatments were established: well-watered (WW), drought (D), grafting + BNS + drought (G+B+D), grafting + drought (G+D), and BNS + drought (B+D), each with three independent biological replicates. Under moderate-to-severe drought conditions (DSI 62-64%; VWC ~12% v/v at 14 days), the combined G+B+D treatment significantly improved plant height (3.05-fold over D), leaf relative water content (83% vs 49% in D), net photosynthetic rate (2.0-fold over D), water-use efficiency (+40%), and antioxidant enzyme activities (SOD: 3.1-fold; CAT: 2.8-fold over D), while reducing lipid peroxidation by 76%. Root architecture was also substantially enhanced, with a 4.1-fold increase in root length and a 3.1-fold increase in root surface area relative to D. Fruit yield increased by 79% relative to drought-stressed non-grafted plants. Transcriptomic analysis using Illumina NovaSeq 6000 identified 1,051 DEGs (431 upregulated, 620 downregulated; FDR < 0.05, |log2FC| > 1). Integrated transcriptomic-phenotypic concordance analysis revealed enrichment of MAPK signalling, ABA-mediated regulation (including ABA binding and (+)-ABA 8'-hydroxylase activity), and phenylpropanoid biosynthesis as the enriched pathways. Protein-protein interaction network analysis further revealed coordinated regulation of redox homeostasis, drought-responsive hormone signalling, and water transport gene modules in the combined treatment. These findings demonstrate that integrating grafting with biodynamic nanosilica is a promising strategy to enhance drought resilience and productivity in chilli, offering a sustainable approach for vegetable production under drought.

Capsicum↗

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

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↗

PubMed2026

Comparative in silico analysis of Apis mellifera immune responses to Varroa destructor and Tropilaelaps mercedesae: Common and mite-specific molecular signatures.

Parasitic mites Varroa destructor and Tropilaelaps mercedesae represent major threats to global honey bee (Apis mellifera) health and productivity, yet comparative molecular insights into host responses remain limited. To address this, we systematically compiled published studies (2015-2025) reporting genes associated with honey bee interactions with V. destructor (11 studies, 87 genes), T. mercedesae (4 studies, 35 genes), and hygienic behavior (6 studies, 44 genes). Gene identifiers were harmonized to the Amel_HAv3.1 genome assembly, yielding three non-redundant sets: 64 Varroa-associated, 34 Tropilaelaps-associated, and 44 hygienic behavior-associated genes. Venn analysis identified 10 overlapping genes (including A0A088A8D5, A0A088ADL8, ABAE_APIME, Def1, Def2, Gapdh, HYTA_APIME, Imd, LOC726783, and Vg), suggesting conserved defense mechanisms, while 41 and 24 genes were uniquely associated with Varroa and Tropilaelaps, respectively. Enrichment analyses revealed Varroa-responsive genes were enriched in immune processes, chitin catabolism, and signaling pathways (Toll/Imd, MAPK, Wnt). Tropilaelaps-associated genes were enriched for antibacterial defense and stress response, with Toll/Imd signaling as the sole significantly enriched pathway. Overlapping genes reinforced core innate immunity activation. Protein-protein interaction network centrality analysis identified key hub genes: Def1, HYTA_APIME, ABAE_APIME, PPO, Imd, PGRP-LC, Vg for Varroa; and ACPH1_APIME, MRJP1, Vg, LOC726783 for Tropilaelaps. Results demonstrate that, despite differences in mite biology, honey bees show a conserved immune response against both parasites, centered on antibacterial defense, humoral immunity, and activation of the Toll/Imd pathway. Although limited by the in-silico nature and research asymmetries reflecting Tropilaelaps' emergence, this curated resource establishes a comprehensive framework for elucidating shared and distinct molecular defense mechanisms. Ultimately, this approach prioritizes diagnostic markers and candidate genes for functional validation and breeding strategies to enhance colony resilience against mite‑driven disease globally.

Animals↗