Silencing of OsGRXS17 in rice improves drought stress tolerance by modulating ROS accumulation and stomatal closure

Abstract

Glutaredoxins (GRXs) modulate redox-dependent signaling pathways and have emerged as key mediators in plant responses to environmental stimuli. Here we report that RNAi-mediated suppression of Oryza sativa GRXS17 (OsGRXS17) improved drought tolerance in rice. Gene expression studies showed that OsGRXS17 was present throughout the plant and that transcript abundance increased in response to drought stress and abscisic acid (ABA) treatment. Localization studies, utilizing GFP-OsGRXS17 fusion proteins, indicated that OsGRXS17 resides in both the cytoplasm and the nuclear envelope. Under drought stress conditions, rice plants with reduced OsGRXS17 expression showed lower rates of water loss and stomatal conductance, higher relative water content, and enhanced survival compared to wild-type controls. Further characterization of the OsGRXS17 down-regulated plants revealed an elevation in H2O2 production within the guard cells, increased sensitivity to ABA, and a reduction in stomatal apertures. The findings demonstrate a critical link between OsGRXS17, the modulation of guard cell H2O2 concentrations, and stomatal closure, expanding our understanding of the mechanisms governing plant responses to drought.

Redox response of iron-sulfur glutaredoxin GRXS17 activates its holdase activity to protect plants from heat stress

“…GRXS17 was previously proposed to improve thermo-, drought- and oxidative-tolerance by enhancing ROS scavenging capacities and expression of Heat-Shock Proteins. This might occur by modulation of gene expression, enzyme activity or protection of antioxidant enzymes (Wu et al, 2012, 2017; Hu et al, 2017). Our data suggest an additional function of GRXS17 through its chaperone activity.…”

“…However, for most of its partners, the role of the Fe-S cluster remained enigmatic. Genetic evidence from different plant species suggests a protective role of GRXS17 during thermal, genotoxic and drought stress (Cheng et al, 2011; Wu et al, 2012; Wu et al, 2017; Iñigo et al, 2016; Hu et al, 2017), in meristem development (Knuesting et al, 2015), hormonal responses (Cheng et al, 2011), and during redox-dependent processes (Yu et al, 2018).…”

Genome-Wide Association of Rice Response to Blast Fungus Identifies Loci for Robust Resistance Under High Nitrogen.

“…In order to understand the possible genetic basis of the observed increased susceptibility in the high nitrogen environment, the 126 genes annotated at NIS3 were investigated (Additional le 15). We considered as good candidates genes either involved in biotic stress response (twenty-nine pathogenesisrelated genes), abiotic stress response (OsTIP3;1, [64] and RIPER6 [65]), the regulation of both stresses (OsGRXS17, [66] and OsTPR1 [67]), or nitrogen metabolism (OsPORB, [68] and a polylpolyglutamate synthetase [69]). The possible modulation of the M. oryzae pathogenicity program in response to a high nitrogen environment was also a hypothesis based on our previous results [26].…”

<strong>When water runs dry and temperature heats up: </strong><strong>Understanding the mechanisms in rice tolerance to drought and </strong><strong>high temperature stress conditions</strong>

“…Phenotyping of IR64-derived near-isogenic lines (NILs) with varying leaf size showed that plants with broad leaves performed better than those with short and narrow leaves (Farooq et al, 2010). Change in leaf size, together with stomatal opening and closure can be an adaptive mechanism for plants to minimize water loss (Farooq et al, 2010, Hu et al, 2017. Leaf size is an important agronomic trait in rice and was shown to moderately correlate to panicle numbers (Rabara et al, 2014a).…”