Quinoa (<i>Chenopodium quinoa </i>Willd.) Genome-Wide Analysis of Glutathione S-transferase (<i>CqGSTs</i>) and Transcription Factor <i>bHLH</i> Family Study on Their Salt Tolerance Function

Since the industrial Revolution, as the global economy has boomed and the agricultural population has expanded. Excessive use of chemical fertilizer and unreasonable farming methods make soil salinization more and more serious. Chenopodium quinoa, it has unique nutritional value and strong stress resistance and adaptability, under the background of soil salinization, quinoa has been widely studied as a halophyte model. With the release of high-quality genome of quinoa, more and more salt-tolerant genes of quinoa have been cloned gradually. Bioinformatics and expression analysis of GST gene in quinoa in this study, 114 CqGST genes were identified from the whole genome of quinoa by bioinformatics methods. The phylogenetic tree showed that 114 CqGST genes were divided into seven subgroups: GSTU (68 members), GSTF (23 members), GST members), GSTZ (6 members), GSTT (5 members), DHAR (4 members) and TCHQD (2 members). Gene structure and Motif analysis showed high similarity among members of each subgroup. Phylogenetic analysis of these genes suggested that tandem and fragment replication events played a key role in the expansion of the CqGSTs gene family, and the CqGST genes may have undergone strong purification selection during the evolution process. Analysis of salt-treated transcriptome from the roots of salt-tolerant and salt-sensitive quinoa cultivars showed that Salt treatment induced changes in the expression levels of CqGSTs genes, and eight CqGST genes (CqDHAR2, CqDHAR3, CqGSTU22, CqGSTU44, CqGSTU60, CqGSTU63, CqGSTU67, CqGSTU68) were steadily up-regulated in both cultivars. RT-qPCR results showed that these selected CqGST genes were not only induced by salt stress, but also by drought stress.