Plant stress responses

Reactive oxygen species (ROS) signalling is crucial in plant responses to abiotic and biotic stresses. This Review discusses our current understanding of ROS regulation and sensing in plants, key regulatory hubs that connect ROS signalling with other stress-response pathways and how ROS signalling could be harnessed to increase plant resilience to environmental stress.

Abiotic stresses, such as drought, salinity, heat, cold and flooding, have profound effects on plant growth and survival. Adaptation and tolerance to such stresses require sophisticated sensing, signalling and stress response mechanisms. Shroeder and colleagues discuss recent insights into how plant hormones control such responses. Understanding these mechanisms opens opportunities for agricultural applications.

RNA silencing through small RNAs is a major antiviral immunity system in plants. Recent findings are uncovering the roles of RNA silencing in immunity against non-viral pathogens, which is mediated by trans-kingdom RNA movements in vesicles or as extracellular nucleoproteins. RNA silencing also enables the crosstalk between other plant immunity systems.

Julia Bailey-Serres highlights early work on the molecular mechanisms of plant stress responses, indicating that selective translation is a key driver of plant resilience to acute stresses.

Rashmi Sasidharan highlights the work by Musgrave et al. (1972) demonstrating that ethylene drives shoot elongation in plants submerged in water, allowing the plant to outgrow the floodwaters.

Steinhorst et al. show how calcium signal induced by salt stress is ‘decoded’ by plant roots to provide systemic response and to increase salt tolerance.

Translation reprogramming in plants in response to innate-immunity induction relies on a novel cap-independent translation pathway.

Yang, Zhu et al. describe temperature-dependent structural conformations of COOLAIR lncRNA and their impact on flowering time.

Suppression of salicylic acid production in Arabidopsis thaliana at high temperature is caused by decreased recruitment of GUANYLATE BINDING PROTEIN-LIKE 3 defence-associated condensates on promoter sites of master immune regulatory genes.

A plant endogenous peptide-receptor signaling pathway termed SCREW–NUT is described; it counteracts microbe-associated molecular pattern (MAMP)- and abscisic acid-induced stomatal closure to regulate the reopening of stomata after biotic and abiotic stresses.

A family of plant guanylate-binding protein-like GTPases controls phase separation and assembly of condensates, thereby forming a circuit that regulates transcriptional responses to biotic stress.

Heat stress transcription factors (HSFs) play critical roles in response to heat stress. This study reveals a new regulatory mechanism in Arabidospis by which ALBA proteins stabilize HSFs in cytoplasmic granules under heat stress.

Heat sensing is not well understood in plants. Here the authors show that high temperature induces the production of nitric oxide conjugate S-nitrosoglutathione in the shoot meristem. A systemic long-distance signalling pathway then includes nitrosylation of transcription factor GT-1, which activates heat-responsive genes such as HsfA2.

TT2 is identified as a negative regulator of thermotolerance. It triggers Ca²⁺ signalling upon heat stress, which is then decoded by SCT1–CaM interaction. SCT1 reduces the transcription of its target OsWR2, thereby causing reduction in wax biosynthesis.

Advances in omics provide a tool to understand mechanisms for plant–microbial interactions under stress. Here the authors apply genome-resolved metagenomics to investigate sorghum and its microbiome responses to drought, identifying an unexpected role of iron metabolism.

Forest dynamics are monitored at large scales with remote sensing, but individual tree data are necessary for ground-truthing and mechanistic insights. This study on high temporal resolution dendrometer data across Europe reveals that the 2018 heatwave affected tree physiology and growth in unexpected way.

The role of non-structural carbohydrates (NSC) in mediating the impacts of drought in tropical trees is unclear. Here, the authors analyse leaf and branch NSC in 82 Amazon tree species across a Basin-wide precipitation gradient, finding that allocation of leaf NSC to soluble sugars is higher in drier sites and is coupled to tree hydraulic status.

In a meta-analysis comparing experimental versus observational studies of aboveground biomass responses to drought in grasslands, the authors show that effect sizes in experiments are 53% weaker than in observational studies, suggesting that experiments are underestimating drought responses.

Structural overshoot can occur when phases of excess plant growth deplete soil moisture too rapidly. The authors quantify structural overshoots using remote sensing datasets from 1981 to 2015, finding that 11% of droughts during this period could be attributed to structural overshoot.

A study of global tree ring data records over the last century reveals a temporal trade-off between resistance and resilience to drought for gymnosperms.