Duet between sugars and hormones: The molecular dialogue fine-tuning hypoxia acclimation in plants.

Molecular and physiological mechanisms of drought tolerance in grapevine

This review synthesizes recent advances in elucidating the molecular and physiological mechanisms underlying drought tolerance in Vitis vinifera to provide an integrative conceptual framework to support sustainable viticulture in water-limited environments.

Sugars as Central Integrators of Plant Immunity and Stress Responses.

Sugars are fundamental metabolites that sustain plant growth and development, but accumulating evidence demonstrates that they also function as regulatory hubs in plant defence. In this review, we synthesise current knowledge on how carbohydrate dynamics coordinate metabolism, signalling, and structural responses to shape plant resistance against both pathogens and herbivores. We highlight how spatial and temporal regulation of sugar transport, mediated by SWEET, SUT/SUC, and STP transporters, controls carbon availability at plant-heterotroph interfaces, while sucrose-cleaving enzymes such as invertases and sucrose synthase modulate local sugar composition to support defence metabolism or restrict nutrient access to attackers. Beyond metabolic functions, sugars act as signalling molecules that regulate immune responses through complex sensing and energy-signalling networks. Central to this framework are trehalose-6-phosphate and the antagonistic kinases SnRK1 and TOR, which integrate carbon status with growth-defence decisions. These pathways are closely interconnected with phytohormone signalling, forming a bidirectional regulatory network that enables plants to tailor defence responses according to attacker lifestyle, including biotrophic and necrotrophic pathogens as well as sap-sucking and chewing herbivores. In parallel, carbohydrate-based cell wall remodelling reinforces physical barriers and generates damage-associated molecular patterns that activate immune signalling. We further discuss how carbohydrates contribute to immune priming, enhancing resistance while minimising fitness costs. Collectively, this review highlights sugars as central regulators that coordinate carbon allocation with immune activation across multiple biological scales, providing promising opportunities for developing sustainable strategies to enhance crop resistance against pathogens and herbivores.

Ethylene as a Systems-level Integrator of Plant responses to Drought and Heat stress.

Ethylene (ET) functions as a central integrator of plant responses to drought and heat stress by linking hormone signaling, metabolism, and chromatin regulation. Its biosynthesis and perception are tightly controlled through ACC synthase/oxidase activity and ER-localized receptors that regulate the ETR-CTR1-EIN2-EIN3 signaling cascade. Under drought, ethylene modulates growth restraint, root architecture, and stomatal behavior, often acting in coordination or opposition with ABA to balance water conservation and carbon assimilation. Soil drying and compaction further influence ethylene diffusion, shaping local hormone signaling and root growth responses. Under heat stress, ethylene promotes thermotolerance by enhancing ROS buffering, activating HSF-HSP pathways, and stabilizing cellular homeostasis. These contrasting roles reflect distinct physiological priorities: drought emphasizes water economy, whereas heat prioritizes proteostasis and survival. Ethylene's effects are therefore highly context dependent, governed by stress intensity, tissue specificity, and developmental stage. Effective crop improvement strategies should focus on tuning ethylene sensitivity and downstream transcriptional modules rather than globally suppressing ethylene signaling, enabling optimized resilience to combined climate stresses.

Drought and sugar transport: From turgor sensing to carbon allocation.

Drought triggers reprogramming of sugar transport, which acts as a central hub linking stress perception to carbon allocation. Under drought, FERONIA acts as a cell wall-plasma membrane turgor sensor that activates SnRK2s via outside-in signaling, and stress-activated kinases (SnRK2s, CPKs, and CIPKs) directly phosphorylate SWEET, SUT1, and TST transporters to enhance long-distance sucrose transport and vacuolar sugar accumulation. Recent cross-species single-cell atlases have identified phloem foundational genes as new targets for improving sugar transport. Meanwhile, deep mutational scanning enables high-throughput screening for SWEETs with enhanced sucrose transport activity. Remaining challenges include the need for characterization of sugar unloading in sink tissues. Thus, sugar transport integrates drought perception with metabolic adjustment, providing principles for engineering carbon partitioning under drought.

Physiological, Biochemical, and Molecular Basis of Plant Responses to Drought Stress

This comprehensive framework underscores the remarkable capacity of plants to adapt to drought stress through an integrated network of physiological, biochemical, and molecular strategies, holding promise for enhancing crop resilience and agricultural sustainability in water-scarce environments.

Decoding the Hydro-Metabolic Switch: Mechanistic Insights into Stochastic Environmental Disruption of Mango Phenology