Abstract
Two-component systems (TCSs) have been identified as participants in mediating plant response to water deficit. Nevertheless, insights of their contribution to plant drought responses and associated regulatory mechanisms remain limited. Herein, a soybean response regulator (RR) gene RR34, which is the potential drought-responsive downstream member of a TCS, was ectopically expressed in the model plant Arabidopsis for the analysis of its biological roles in drought stress response. Results from the survival test revealed outstanding recovery ratios of 52%–53% in the examined transgenic lines compared with 28% of the wild-type plants. Additionally, remarkedly lower water loss rates in detached leaves as well as enhanced antioxidant enzyme activities of catalase and superoxide dismutase were observed in the transgenic group. Further transcriptional analysis of a subset of drought-responsive genes demonstrated higher expression in GmRR34-transgenic plants upon exposure to drought, including abscisic acid (ABA)-related genes NCED3, OST1, ABI5, and RAB18. These ectopic expression lines also displayed hypersensitivity to ABA treatment at germination and post-germination stages. Collectively, these findings indicated the ABA-associated mode of action of GmRR34 in conferring better plant performance under the adverse drought conditions.
Highlights
Being immobile, plant growth and development are vulnerable to environmental changes [1].Under overpopulation and climate change pressures, water crisis has become the major concern of many countries around the world and affects multiple aspects of human life including health care, environment and food availability [2,3,4]
GmRR34 associating with plant tolerance to water deficit
GmRR34 under normal condition, measured by RT-qPCR, confirmed transgenic plantsofwere subjected to the growth examination of GmRR34 expression and phenotypic characteristics
Summary
Plant growth and development are vulnerable to environmental changes [1].Under overpopulation and climate change pressures, water crisis has become the major concern of many countries around the world and affects multiple aspects of human life including health care, environment and food availability [2,3,4]. Genetic engineering has appeared as a practical strategy to deal with water scarcity, upon which novel cultivars with better drought tolerance are developed based on the comprehensive understanding of plant responses under stress conditions and identification of key genes for genetic manipulation [7,8,9,10]. Plants have adopted a variety of defense mechanisms that lessen the negative effects of environmental adversities on plant growth and productivity [11]. These activities are involved in various molecular, biochemical, and physiological adjustments [12], and are under regulation of various stress-related signaling pathways [13,14,15,16]. A number of overlapping components and crosstalk among different pathways have been identified, suggestively to form a dynamic network in synchronically mediating plant responses to the tough adverse conditions [16,19,20]
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