RT-qPCR analysis of antioxidants, sugar synthesis and symbiosis-related gene expression in soybean plants under water deficiency
As shown in the Fig. 9A, the expression level of GmCAT was appreciably down-regulated by Q8 and Q8+NaHS treatments under three water conditions. Similarly, the expression abundance of GmSOD1was significantly down-regulated by Q8 and Q8+NaHS treatments under any water content conditions (Fig. 9B). On contrast, the expression abundances of GmSOD2 was greatly up-regulated by 49.3 and 144.1 fold in the Q8 and Q8+NaHS treatment compared with that of the control treatment under SW condition, respectively (Fig. 9C). Additionally, compared with control treatment, the expression levels of GmPrx ,GmGrx and GmBADH were substantially down-regulated in Q8+NaHS treatment under MW condition, but were up-regulated to different degrees under SW condition (Fig. 9E-F). With the decrease of water content, the expression abundance of GmSUS was not remarkably different among four treatments. In addition, in the Q8+NaHS treatment, the expression level of GmSUS was considerably lower than control treatment under any water content conditions (Fig. 9G). Under three water conditions, the expression abundance of GmUDP showed a appreciably down-regulation in Q8+NaHS treatment. With the decrease of water content, NaHS treatment apparently increased the expression abundance of GmUDP in leaves, and this gene’s expression abundance showed different degrees of down-regulation under control, Q8 and Q8+NaHS treatments (Fig. 9H). The GmFBP expression level of 13.3 fold difference was detected by Q8+NaHS treatments compared with control treatment under SW condition. In control and Q8+NaHS treatments, the expression level of GmFBP was increased by the decrease of water content, but NaHS and Q8 treatments exhibited a trend of increasing first and then decreasing (Fig. 9I). In order to further elucidate the mechanism of H2S promoted nodulation in soybean, we examined the expression of several nodulation marker genes including GmENOD40 , GmERN , GmNIN1a , GmNIN2a , and GmNIN2b in soybean roots. The qRT-PCR results demonstrated that H2S stimulated the expression levels of these genes in soybean roots. For instance, under whatever water condition, Q8 and Q8+NaHS treatments greatly elevated the expression levels ofGmENOD40 , GmERN , GmNIN1a , GmNIN2a , andGmNIN2b (Fig. 10A-E) in the inoculated roots during the entire treatment period. As for control and NaHS treatments did not give rise to any notably difference in the non-inoculated soybean roots.