Differential Expression of Two-Component System–Related Drought-Responsive Genes in Two Contrasting Drought-Tolerant Soybean Cultivars DT51 and MTD720 Under Well-Watered and Drought Conditions

Abstract

Two-component systems (TCSs) have been shown to participate in plant responses to drought. In this study, results of real-time quantitative PCR (RT-qPCR) of 26 selected dehydration-responsive TCS-related genes in roots and shoots of two Vietnamese soybean cultivars (DT51 and MTD720) with contrasting drought-tolerant phenotypes suggest a positive correlation between the number of droughtinducible TCS genes and their drought-tolerant ability. In addition, expression analyses of the roots and shoots indicated that DT51 and MTD720 had distinct drought-responsive TCS expression profiles, suggesting that expression of TCS-related genes are genotype and tissue dependent. Furthermore, nine TCS genes (GmHK07, 16, GmHP08, GmRR04, 16, 32, 34, GmPRR39, and 44) potentially associated with enhanced drought tolerance were identified. Particularly, GmRR34, showing its higher expression levels under both normal and drought conditions in DT51 roots versus MTD720 roots, might be a potential positive regulator of drought tolerance. On the other hand, GmPRR44 was highly recommended as a potential negative regulator of drought tolerance because it exhibited lower expression levels in both tissues of the drought-tolerant DT51 than in those of the drought-sensitive MTD720 under both stressed and unstressed conditions. These two genes deserve in-depth characterization as promising candidates for development of soybean cultivars with improved drought tolerance by using genetic engineering.

Role and Regulation of Cytokinins in Plant Response to Drought Stress

“…In part of this study, transcripts of two GmHP genes (GmHP03 and GmHP06) displayed higher levels under dehydration treatment [98]. Consistent with these reports, Thu et al (2015) found that GmHK07 was potentially associated with an enhanced drought tolerance phenotype after performing comparison in expression profiles of dehydration-responsive TCS genes between two Vietnamese soybean cultivars with contrasting drought-tolerant phenotypes [99]. Although more experimental evidence, such as in planta studies, is needed to support mechanistic models of GmHK07, it seems reasonable to assume that GmHK07 might be a key component in mediating drought tolerance in soybean.…”

Meta-analysis of the effects of overexpression of WRKY transcription factors on plant responses to drought stress

“…Drought is a type of dehydration stress and largely restricts crop productivity and quality. Improving crop tolerance to drought stress is an effective strategy for the promotion of sustainable agriculture in most crop production regions worldwide [1]. There has been extensive research on plant responses to drought stress at the morphological [2–6], physiological [2, 7–15], and biochemical [16–21] levels.…”

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

“…Previous studies have provided strong lines of evidence for the participation of the soybean type-C RR gene GmRR34 in drought stress responses [35,36]. According to these reports, expression of GmRR34 was markedly up-regulated in root and/or shoot tissues under drought [36] and dehydration [35]. Furthermore, sequence analysis of GmRR34 recognized a cis-motif MYCR (myelocytomatosis-related protein recognition site) in its 1000-bp promoter region [30].…”

“…Among these genes, GmRR34, a type-C RR, was found to be intensively induced upon exposure to 10-h-dehydration treatment. A subsequent study of TCS genes using Vietnamese drought-tolerant and drought-sensitive soybean cultivars revealed nine genes (i.e., 2 HK-, 1 HP-, and 6 RR-encoding genes) that might have positive involvement in mediating plant adaptation to water-deficit conditions, as their expression levels were enhanced significantly in the former cultivar [36]. Interestingly, GmRR34 was also a member of this candidate list.…”