Heterologous Expression of a Soybean Gene RR34 Conferred Improved Drought Resistance of Transgenic Arabidopsis

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.

Expression study of stress-related genes in salinity-treated transgenic Arabidopsis harboring soybean Response Regulator 34

“…Among those, TCS has been identified as one of the most evolutionarily conserved signaling cascades in regulating plant stress response (Grefen, Harter, 2004). Previous studies have discovered the involvement of the soybean TCS member GmRR34 in relation to drought (Le et al, 2011;Thu et al, 2015;Nghia et al, 2020). Therefore, in this study, we further explored the involvement of GmRR34 in another type of osmotic stress, salinity.…”

“…The cDNA of soybean GmRR34 was cloned into vector pBI121 and placed under the control of promoter CaMV 35S (Nghia et al, 2020). The recombinant vector was transferred into Agrobacterium, followed by transformation into Arabidopsis (Col-0) as described in previous study (Zhang et al, 2006).…”

“…The recombinant vector was transferred into Agrobacterium, followed by transformation into Arabidopsis (Col-0) as described in previous study (Zhang et al, 2006). The transgenic line used in this study has been verified to carry homozygous, single copy of transgene, according to the Mendelian genetic laws (Tizaoui, Kchouk, 2012;Nghia et al, 2020). The wild-type (WT) plants (Col-0) were used as control.…”

“…Among those, there are 9 genes (2 HKs, 1 HP and 6 RRs) have been found to potentially associate with the drought tolerance capacity of plants (Thu et al, 2015). In particular, in planta functional characterization of GmRR34, one gene in this list, has shown that this soybean RR can significantly enhance plant tolerance toward the drought stress (Nghia et al, 2020). It has been known that water deficiency and salinity both cause osmotic and oxidative stresses as well as trigger similar responses in plants (Okon, 2019).…”

The Roles of Cytokinins in Plants and Their Response to Environmental Stimuli

“…They conclude with a call for more basic knowledge of CK hormonal biology that can be applied for selection of new regulatory controls for plant drought adaptation. These authors answered their own call, to some extent, in a subsequent contribution to this Special Issue with a report on the effects of heterologous expression of a CK response regulator and apparent improvements to drought resistance [ 8 ]. This paper delves into the CK signal transduction pathway by manipulating a soybean response regulator (RR34) which operates as a potential drought-responsive agent situated downstream of the CK two-component system (TCS) of detection and transduction.…”