Plant signaling & behavior最新文献

Plant growth and stress regulation are tightly regulated by phytohormone signals which are jasmonic acid (JA) and gibberellic acid (GA). Antagonistic crosstalk between JA and GA signaling pathways is mediated by repressor proteins, including JASMONATE ZIM-DOMAIN PROTEINs (JAZ) in the JA and DELLA proteins in the GA. In rice (Oryza sativa), the interaction between OsJAZ9 and rice DELLA protein SLENDER RICE 1 (SLR1) has been identified as a key role in the antagonistic interplay between JA and GA.In this study, we generated transgenic rice lines constitutively overexpressing a truncated form of OsJAZ9 that retains the N-terminal ZIM domain but lacks the C-terminal Jas domain (OsJAZ9NZ-OE). We hypothesized that this construct could alter JAZ-DELLA interactions and thereby affect both JA- and GA-associated processes. OsJAZ9NZ-OE plants displayed increased plant height and improved recovery under drought stress. At the transcriptional level, OsbHLH148 and OsMYC2 (JA-associated) and OsWRKY71 (ABA/stress-associated), and the GA-related transcription factors OsPIL14 and OsPIL15 were all upregulated, indicating that OsJAZ9NZ influences a broad set of hormone-responsive pathways that coordinate growth and stress responses.These findings indicate that structural modification of OsJAZ9 alters JA-GA signaling balance and is associated with transcriptional reprogramming that affects both growth and drought tolerance. While further work is required to clarify the underlying mechanisms, OsJAZ9NZ provides a useful genetic tool to probe hormone crosstalk and may represent a promising genetic resource for crop improvement under environmental stress.

In real-life scenarios, plants are often exposed to biotic and abiotic stresses simultaneously; it is crucial to understand how they respond to single and combined stresses. This study explored the physiological and molecular responses of two contrasting alfalfa varieties, Gabes-2353 (tolerant) and Magna-601 (sensitive), to salinity and/or Ascochyta medicaginicola infection. Both varieties exhibited reductions in stem length, leaf relative water content, and chlorophyll content, with a greater decrease in Magna-601. Label-free LC‒MS/MS analysis identified 128 differentially abundant proteins (DAPs) between the two varieties, of which 14, 60, and 70 proteins were differentially regulated under salinity, Pm8 infection, and combined stresses, respectively. Gene Ontology analyses revealed that Gabes-2353 activated photosynthesis, metabolism, redox balance, and immune pathways, while Magna-601 disrupted carbohydrate metabolism. Pm8 infection induced immune pathways in both varieties, with antioxidant and metabolic proteins expressed in Gabes-2353, while protease inhibitors and defense proteins were expressed in Magna-601. Under combined stress, Gabes-2353 upregulated proteins associated with synergistic integration of metabolic and immune pathways. In contrast, Magna-601 activated broad stress-signaling responses but inhibited primary metabolism, aminoacyl-tRNA biosynthesis, and vitamin metabolism. The PPI and KEGG analyses identified 7-O-methyltransferase as a central hub in Gabes-2353, while Magna-601's PPI network focused on starch mobilization, reflecting differential adaptation strategies.

Root gravitropism enables plants to optimize water and nutrient uptake, with actin filaments playing a key regulatory role. However, the effects of F-actin depolymerization on gravitropism have been inconsistent. Here, we show that actin depolymerization impacts root gravitropism in a developmentally dependent manner. In newly germinated roots, weak statolith constraint by actin means depolymerization does not significantly enhance statolith sedimentation but inhibits cell elongation on the upper root side, reducing gravitropic bending. In mature roots, stronger statolith constraint allows actin depolymerization to promote statolith sedimentation and inhibit cell elongation on the lower side, thus accelerating root bending. These findings provide new perspectives for a deeper understanding of the mechanisms underlying root gravitropism.

Melatonin, a key indoleamine compound intrinsic to life, is ubiquitously distributed across the plant kingdom in plants. As a plant growth regulator and biostimulant, melatonin plays a pivotal role in both increasing plant growth and bolstering resilience to stress. This review provides a comprehensive analysis of regulatory mechanisms plant growth and development and addresses biotic and abiotic stressors. We dissect the biosynthetic and metabolic pathways of melatonin in plants and elaborate on its roles in catalyzing plant growth, development, and antioxidant activities. Furthermore, our discussion delves into the ways in which melatonin manipulates plant morphology, physiology, redox systems, ion homeostasis, biomolecular content levels, and the expression of stress resistance genes or proteins. We additionally highlight its cooperative interaction with other endogenous hormones in mitigating the deleterious impacts of challenging environments. In essence, melatonin, as a multifunctional biological signaling molecule, offers the potential to increase crop yield even under adverse conditions by plant seed germination rates and promoting robust growth. Consequently, it as a compelling candidate for ecofriendly crop production strategies. This review is intended to serve as a theoretical guide to unravel the multifaceted regulatory mechanisms of melatonin in governing plant growth, development, and stress resistance.

Fritillaria taipaiensis is a valuable traditional Chinese medicinal plant that is prone to germplasm degradation during long-term continuous monoculture. Allelopathic autotoxicity, which is mediated primarily by phenolic acids, is considered a major factor contributing to this degradation. To reveal the accumulation patterns of phenolic acids in the rhizospheric soil of F. taipaiensis under continuous monoculture, five phenolic acids (p-hydroxybenzoic acid, vanillic acid, syringic acid, p-coumaric acid, and ferulic acid) in the rhizospheric soil of F. taipaiensis across 1-5 y, and various fertilizer regimes (chemical fertilizer, chemical fertilizer + organic fertilizer, and organic fertilizer) were determined to assess their accumulation characteristics, along with soil fertility parameters. The result showed that the levels of available nitrogen, Olsen-phosphorus, and available potassium in chemical fertilizer and chemical fertilizer + organic fertilizer, along with the organic matter content in all three soil samples, showed a decreasing trend over time, while organic fertilizer exhibited significant fluctuations without a clear pattern. The phenolic acid content in the rhizospheric soil initially increased and then generally decreased in later stages. After 5 y of cultivation, the soils treated with organic fertilizer exhibited lower phenolic acid levels than those treated with chemical fertilizer. The accumulation patterns of individual phenolic acids varied with fertilizer type and cultivation period, with organic fertilizer showing the most consistent patterns across all phenolic acids. There was a positive correlation among the five phenolic acids, along with a significant positive correlation between soil organic matter and vanillic acid and ferulic acid. These findings suggest that long-term monoculture leads to distinct accumulation characteristics of phenolic acids in the rhizospheric soil of F. taipaiensis, and the application of organic fertilizer can mitigate such accumulation.

Salinity stress severely limits soybean (Glycine max L.) productivity by disrupting physiological and biochemical processes. This study investigated the potential of magnesium oxide nanoparticles (MgO-NPs) to mitigate salt-induced damage. Soybean plants were grown under two salinity levels-non-saline (0 mM NaCl) and saline (75 mM NaCl)- in a controlled pot experiment. At the trifoliate stage, leaves were sprayed with MgO-NPs at 0, 100, 200, 400, and 600 ppm. Salinity markedly reduced relative water content (RWC) (to 69%), photosynthetic rate (to 20 µmol CO₂ m^-2 s^-1), and membrane stability index (MSI) (to 56%), while increasing oxidative stress markers. Foliar application of 400 ppm MgO-NPs significantly alleviated these effects, increasing RWC to 87%, photosynthesis to 35 µmol CO₂ m^-2 s^-1, and MSI to 78%. Treated plants showed higher chlorophyll and carotenoid contents, along with elevated proline and soluble sugars and reduced malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels. Antioxidant activity improved modestly under both saline and non-saline conditions. Importantly, 400 ppm MgO-NPs enhanced yield traits under salinity, increasing pod number, 100-seed weight, and seed yield per plant by about 30%-38%. These results indicate that MgO-NPs, particularly at 400 ppm, effectively mitigate salinity stress by modulating physiological and biochemical mechanisms, with strong potential for improving soybean performance under saline environments. Field studies are suggested to validate practical application.

Asymmetric cell divisions (ACDs) in the root ground tissue of Arabidopsis thaliana are essential for middle cortex (MC) formation, which contributes to root architecture and environmental adaptability. Here, we demonstrate that brassinosteroids (BRs) and gibberellins (GAs) antagonistically regulate MC formation via reactive oxygen species (ROS). Brassinolide (BL, a BR) or paclobutrazol (PAC, a GA biosynthesis inhibitor) promoted MC formation and sporadic periclinal cell divisions in root endodermal cell files, whereas brassinazole (BRZ, a BR biosynthesis inhibitor) or GA₃ suppressed them. Consistently, the BR-signaling gain-of-function mutant bzr1-1D, the GA-biosynthesis-deficient mutant ga1-3, and the GA-insensitive mutant gai-1 exhibited elevated H₂O₂ levels and increased MC formation. Conversely, the BR-biosynthesis-deficient mutant det2 and the GA-signaling-enhanced rga/gai double mutant showed reduced ROS accumulation and MC formation. BL or PAC further enhanced MC-forming effects, while BRZ or GA₃ diminished them. This antagonistic regulation of BRs and GAs on MC formation was further validated in double mutants: ga1-3/bzr1-1D displayed an additive promotion, while ga1-3/det2 showed a diminished effect on MC formation. The ROS-deficient rbohD/F mutant exhibited reduced MC formation and attenuated responses to BL or PAC, and ROS scavenging by potassium iodide suppressed the MC-promoting effects of bzr1-1D, ga1-3, and ga1-3/bzr1-1D. These results identify ROS as a central integrator of BR-GA antagonism, linking hormonal regulation to SHR/SCR-mediated ACDs during MC development in Arabidopsis roots.

Adventitious roots (ARs) are crucial for grafted watermelon seedlings, playing vital roles in nutrient absorption, stress resistance, and grafting efficacy. However, the way in which scions regulate endogenous hormones to influence AR formation remains poorly understood. In this study, we constructed watermelon seedlings (WP) using "HXX" as the scion and "Tie Zhen No. 3" as the rootstock. Scion cotyledons removal (WP-1) significantly promoted AR development. In contrast, true leaf removal (WP-2) had minimal effect, while simultaneous removal of both (WP-3) elicited intermediate responses. Endogenous hormone dynamics showed that WP-1 maintained progressively increasing indole-3-acetic acid (IAA) with lower abscisic acid (ABA) and jasmonic acid (JA) levels, whereas both WP-2 and WP-3 exhibited divergent hormonal profiles in ARs during later development stages. Transcriptome sequencing revealed that differentially expressed genes (DEGs) are enriched in various hormone signaling pathways. On the fourth day, when the number of differential genes was the highest, the DEGs significantly expressed in all three treatment groups were enriched in the activation signaling pathways and responses of JA, auxin, ethylene, and cytokinins. Transcription factors such as bHLH, ERF, MYB, and NAC were significantly expressed during the development of ARs, playing a key regulatory role. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified 82 DEGs across five hormone signal transduction pathways. The weighted gene co-expression network analysis (WGCNA) identified modules positively correlated with AR hormones, highlighting hub genes such as ethylene transcription factors (CRF4, ABR1, ERF054, ERF098), auxin response factors (SAUR21 and SAUR32), and other regulators (CSA, HSP, bHLH93, ZAT5, ZAT13, NAC, MYB, and C3H). These findings provide preliminary evidence of the scion's regulatory role in AR development through hormones, offering a foundation for improving watermelon grafting practices.

Senescence is a conserved phenomenon in all living organisms, including plants. The initiation and progression of leaf senescence can be triggered by natural internal factors or induced by external stress conditions. Over the past few decades, several transcriptional regulators, histone deacetylases/acetyltransferases (HDACs/HATs), signaling transduction pathway components, hormonal regulators, and other proteins have been extensively studied and reported to play a role in regulating leaf senescence. However, a deeper molecular understanding of their mechanisms is needed. We recently reported that a WD40-repeat domain protein, HOS15, regulates aging- and dark-induced senescence. Loss-of-function HOS15 mutant plants exhibited a late senescence phenotype with greater chlorophyll content accumulation. The transcript levels of senescence-related (SAG12, SAG29, and ORE1) genes were downregulated in hos15-2 plants compared with those in wild-type (WT) plants, whereas photosynthesis-related (CAB1 and RBCS1A) genes were upregulated. Our studies also revealed that HOS15 works together with PWR-HDA9 complex to associate with the promoters and negatively regulates the expression levels of the senescence negative regulators NPX1, APG9, and WRKY57. Moreover, hos15-2 plants increased H3 acetylation levels, similar to those of hda9 and pwr plants compared to those of WT plants. In addition, the H3 acetylation level was reduced in the dark-induced senescent leaves in WT plants, but not in the hos15-2 plants, which suggests that dark-reduced H3 acetylation requires functional HOS15. Taken together, we conclude that HOS15 together with the PWR-HDA9 complex epigenetically regulates aging- and dark-induced senescence through a common set of genes in Arabidopsis.

Endophytic fungi have emerged as vital allies in enhancing plant resilience to abiotic stresses, offering significant potential for climate-smart agriculture (CSA). This mechanistic review synthesises physiological, biochemical, and molecular pathways through which these symbionts mitigate stress, emphasising mechanistic understanding over descriptive diversity. Key mechanisms include osmotic regulation, ion homeostasis, antioxidant defence, hormonal modulation, and epigenetic reprogramming. As demonstrated by studies on Trichoderma harzianum, Fusarium solani, and Piriformospora indica, such interactions allow plants to sustain photosynthesis, nutrient uptake, and growth when subjected to drought, salinity, heat, and heavy metal stress. Comparative insights highlighted lineage-specific strategies: Ascomycota display broad-spectrum regulation through metabolite production and hormonal control; Basidiomycota specialise in root-fungus signalling and resource acquisition; and Zygomycota contribute primarily to nutrient mobilisation and rapid colonisation. Collectively, these insights reveal that endophytes act as "hidden regulators" of plant stress resilience. Integration of fungal symbionts into CSA practices holds considerable potential for improving productivity, adaptation, and mitigation, particularly in stress-prone agroecosystems. Yet, as several sources have argued, key gaps remain including field performance is inconsistent across host genotypes, beneficial and pathogenic traits sometimes overlap, and inoculant mass production is still limited. Addressing these challenges will necessitate omics-driven innovations, efficient delivery methods, improved relationships between empirical biological research and on-farm application, and policy frameworks. Overall, this synthesis highlights endophytic fungi as essential partners in building resilient and sustainable food systems under changing climates.