Genome-Wide Identification, Sequence Variation, and Expression of the Glycerol-3-Phosphate Acyltransferase (GPAT) Gene Family in Gossypium

Abstract

Cotton is an economically important crop grown for natural fiber and seed oil production. Cottonseed oil ranks third after soybean oil and colza oil in terms of edible oilseed tonnage worldwide. Glycerol-3-phosphate acyltransferase (<i>GPAT</i>) genes encode enzymes involved in triacylglycerol biosynthesis in plants. In the present study, 85 predicted <i>GPAT</i> genes were identified from the published genome data in <i>Gossypium</i>. Among them, 14, 16, 28, and 27 <i>GPAT</i> homologs were identified in <i>G. raimondii, G. arboreum, G. hirsutum</i>, and <i>G. barbadense</i>, respectively. Phylogenetic analysis revealed that a total of 108 <i>GPAT</i> genes from cotton, <i>Arabidopsis</i> and cacao could be classified into three groups. Furthermore, through comparison, the gene structure analyses indicated that <i>GPAT</i> genes from the same group were highly conserved between <i>Arabidopsis</i> and cotton. Segmental duplication could be the major driver for <i>GPAT</i> gene family expansion in the four cotton species above. Expression patterns of <i>GhGPAT</i> genes were diverse in different tissues. Most <i>GhGPAT</i> genes were induced or suppressed after salt or cold stress in Upland cotton. Eight <i>GhGPAT</i> genes were co-localized with oil and protein quantitative trait locus (QTL) regions. Thirty-two single nucleotide polymorphisms (SNPs) were detected from 12 <i>GhGPAT</i> genes, sixteen of which in nine <i>GhGPAT</i> genes were classified as synonymous, and sixteen SNPs in ten <i>GhGPAT</i> genes non-synonymous. Two SNP markers of the <i>GhGPAT16</i> and <i>GhGPAT26</i> genes were significantly correlated with cotton oil content in one of the three field tests. This study shed lights on the molecular evolutionary properties of <i>GPAT</i> genes in cotton, and provided reference for improvement of cotton response to abiotic stress and the genetic improvement of cotton oil content.