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Drought stress inhibits plant growth and agricultural production. Improving plant instantaneous water use efficiency (iWUE), which is strictly regulated by stomata, is an effective way to cope with drought stress. However, the mechanisms of iWUE regulation are poorly understood. Through genetic screening for suppressors of mpk12-4, an Arabidopsis (Arabidopsis thaliana) mutant with a major iWUE quantitative trait locus gene MITOGEN-ACTIVATED PROTEIN KINASE12 deleted, we identified HIGH LEAF TEMPERATURE1 (HT1). Genetic interaction and physiological analyses showed that MPK12 controls iWUE through multiple modules in a high CO2-induced stomatal closing pathway that regulate SLOW ANION CHANNEL-ASSOCIATED1 (SLAC1) activity. HT1 acts downstream of MPK12, whereas OPEN STOMATA1 (OST1) and GUARD CELL HYDROGEN PEROXIDE-RESISTANT1 (GHR1) function downstream of HT1 by activating SLAC1 in iWUE. Photosynthetic-CO2 response curves and biomass analyses under different water-supply conditions showed that HT1 dysfunction improved iWUE and also increased plant growth capacity, and products of HT1 putative orthologs from Brassica (Brassica napus) and rice (Oryza sativa) exhibited functions similar to that of Arabidopsis HT1 in iWUE and the CO2-signaling pathway. Our study revealed the mechanism of MPK12-mediated iWUE regulation in Arabidopsis and provided insight into the internal relationship between iWUE and CO2 signaling in guard cells and a potential target for improving crop iWUE and drought tolerance.
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http://dx.doi.org/10.1093/plphys/kiae377 | DOI Listing |
Plant Physiol Biochem
September 2025
Department of Environmental Biology, Sapienza University of Rome, P.le A. Moro 5, 00185, Rome, Italy; National Biodiversity Future Center (NBFC), Palermo, Italy. Electronic address:
This study investigates the responses of four Mediterranean tree species, Quercus ilex, Viburnum tinus, Acer campestre, and Fraxinus ornus, to urban-relevant abiotic stressors such as soil compaction, water deficit, and over-optimal temperature, applied singly and in combination under controlled experimental conditions. A total of 23 functional leaf traits spanning photosynthesis, water regulation, structural support, and leaf stoichiometry functions were measured. Species identity was the main driver of trait variability.
View Article and Find Full Text PDFThis study assessed variations in leaf intrinsic water use efficiency (iWUE) and δN values among , a genus of drought-deciduous shrubs distributed across arid regions of southwestern North America between 1972 and 1980 when climates were cooler than today. We hypothesized that geographical variations in climate would significantly influence iWUE, a response to water-related climate constraints, and δN values, a proxy for the balance between N fixation and denitrification. Leaf samples were collected from six species of across 78 sites representing the genus range.
View Article and Find Full Text PDFCommun Biol
August 2025
Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou Yangzhou University, Yangzhou, China.
In natural environments, fluctuating light (FL) conditions significantly influence plant growth by modulating the balance between photosynthesis and water loss through stomata, quantified as the intrinsic water use efficiency under fluctuating light (iWUE). This effect is particularly pronounced under drought stress (FL-DS). To elucidate the genetic basis of stomatal responses to FL-DS, we analyzed iWUE variations across 206 rice accessions and identified OsPIL13, a phytochrome-interacting factor, as a key gene associated with iWUE through genome-wide association studies.
View Article and Find Full Text PDFTree Physiol
August 2025
Institut de Recherche sur les Forêts, Groupe de Recherche en Écologie de la MRC Abitibi, Université du Québec en Abitibi-Témiscamingue, 341, Rue Principale Nord, Amos (QC), Canada J9T 2L8.
Pinus banksiana exhibits remarkable ecological adaptability, thriving across diverse environments in the Canadian boreal zone, including clay deposits, fast-draining glacial tills, and rocky outcrops. However, projected rising temperature and increasing vapor pressure deficit (VPD), could increase the species' vulnerability, particularly in dry regions. In this study, we measured basal area increment (BAI) and physiological responses from isotopic fractionation across a soil gradient including three sites in the boreal mixed wood of western Quebec, Canada.
View Article and Find Full Text PDFPlants (Basel)
July 2025
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
Although () is vital in agricultural production and vulnerable to the pathogen , the intracellular water-nutrient metabolism and immunoregulation of infection in leaves remain unclear. This study aimed to analyze the responsive mechanisms of -infected using rapid detection technology. Six soil groups planted with Yangtze No.
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