Plant Stress (Sep 2023)
Genome-wide identification and expression analysis of the Glutamine synthetase family genes in Zea mays under drought stress
Abstract
Glutamine synthetase (GS) enzyme is involved in nitrogen metabolism by the assimilation of NH4+ with glutamate and glutamine, and hence play their role in plant development, biotic and abiotic stress responses, secondary metabolite synthesis and crop yield. However, in maize, the expression levels of ZmGS genes under drought stress are not explored. Globally drought stress significantly affected maize production. Keeping in view the importance of GS genes in maize, we have checked their response under drought stress. The targeted 05 ZmGS genes in maize evolutionary analysis was performed for 81 GS protein sequences in different species, clustered into three clades based on their phylogenetic analysis. GS genes that were identified in maize are distributed on Chromosome 1, chrom4, chrom5, and chrom9. Conserved domain analysis, gene structure, motifs analysis, and alignment of ZmGSs demonstrated that all genes showed a conserved pattern. Analysis of cis-regulatory elements in promoter region revealed that almost all the ZmGS genes had stress responsive and plant hormonal related cis elements and their number are different in all genes. We also identified 55 putative miRNAs targeting 5 ZmGS genes. Furthermore, GS genes of maize were identified as drought-responsive genes by using qRT-PCR expression analysis. The high expression level of GS genes was detected in the roots and leaves of Haq Nawaz compared to CIMMYT PAK maize cultivars. The analysis of all identified ZmGS genes using qRT-PCR data showed that they expressed in roots and shoots under normal and drought stress. The expression analysis of drought-responsive GS genes was found more in H. Nawaz than in C. Pak maize cultivar under drought stress. Therefore, the H. Nawaz cultivar could have the potential to tolerate mild to moderate drought stress. Our study offers valuable data on the functioning of GS genes in maize under drought stress and provides a foundation for further analysis of the function of GS gene family under abiotic stresses.
