Characterization of the GPAT gene family in bean and determination of the function of the PvGPAT1 gene under drought stress with a transgenic approach

GPAT (sn-Glycerol-3-phosphate-1-O-acyltransferase) is a key enzyme in the biosynthesis of membrane lipids. Two types of GPATs are involved in glycerolipid production. sn-1-GPATs are responsible for creating lysophosphatidic acid, whereas sn-2-GPATs produce monoacylglycerol. According to the literature, no study has characterized GPAT genes in Phaseolus vulgaris. This research was conducted to examine the expression patterns of GPAT genes in bean leaves subjected to melatonin, drought, and salt stress, and to carry out a comprehensive genomic analysis of GPAT gene family members using bioinformatics techniques. We also aimed to obtain the chloroplastic PvGPAT1 gene by cloning and determine its function under drought stress by overexpressing this clone in tobacco plants. In this study, 13 PvGPAT genes were detected in the bean genome, with molecular weights ranging from 50,2 kDa to 60,4 kDa, amino acid numbers between 376 and 539, theoretical isoelectric points between 8,41 and 9,46, and instability indexes between 31,84 and 51,38. A phylogenetic analysis was conducted using GPAT proteins from P. vulgaris, Lens culinaris, Glycine max, Arabidopsis thaliana, Vitis vinifera, and Cicer arietinum species. It has been determined that A. thaliana and G. max GPAT proteins are closely related to the PvGPAT genes during the evolutionary process. In qRT-PCR analyses performed with six selected PvGPAT genes, the expression levels of these genes in salt, drought, and melatonin treatments were examined. Moreover, overexpression of PvGPAT1 in tobacco plants under drought stress confirmed that this gene has a regulatory function in the response to drought stress. In light of the data obtained from this study, it is expected to fill the gap in the literature about the role of the PvGPAT1 gene in response to drought stress.