A study on the expresion patterns of GmHK06 and GmRR34 upon water deficit in Mtd777-2 and DT20

Two-component systems (TCSs) form a distinct family of factors which have been reported to participate in the regulation of plant responses upon water-limiting conditions. Previous studies conducted by our group have shown that MTD777-2 had better drought-responsive capacities than DT20. Therefore, in this research, we would like to identify the tissue-specific expression patterns of two TCS members genes encoding a histidine kinase GmHK06 and a response regulator GmRR34 in these two local soybean varieties. The isolated RNA samples from root and shoot of plants grown under normal condition and 15-day drought treatment were used for cDNA synthesis followed by quantitative Real-time PCR. The analyses indicated that under the water stress, GmHK06 expression was repressed in root yet up-regulated in shoot, especially with a higher level in the shoot of MTD777-2. Meanwhile, there was a significant increase in the gene expression of GmRR34 in tissues of both cultivars. These findings suggested that while GmHK06 was a tissue-dependent factor, GmRR34 was a positive regulator against drought stress. Therefore, they could be considered as potential candidate genes for genetic engineering application that need to be deeply studied in future.