Genome-Wide Identification, Evolution, and Expression of GDSL-Type Esterase/Lipase Gene Family in Soybean.

GDSL-type esterase/lipase proteins (GELPs) belong to the SGNH hydrolase superfamily and contain a conserved GDSL motif at their N-terminus. GELPs are widely distributed in nature, from microbes to plants, and play crucial roles in growth and development, stress responses and pathogen defense. However, the identification and functional analysis ofGELPgenes are hardly explored in soybean. This study describes the identification of 194GELPgenes in the soybean genome and their phylogenetic classification into 11 subfamilies (A-K).GmGELPgenes are disproportionally distributed on 20 soybean chromosomes. Large-scale WGD/segmental duplication events contribute greatly to the expansion of the soybeanGDSLgene family. The Ka/Ks ratios of more than 70% of duplicated gene pairs ranged from 0.1-0.3, indicating that mostGmGELPgenes were under purifying selection pressure. Gene structure analysis indicate that more than 74% ofGmGELPgenes are interrupted by 4 introns and composed of 5 exons in their coding regions, and closer homologous genes in the phylogenetic tree often have similar exon-intron organization. Further statistics revealed that approximately 56% of subfamily K members contain more than 4 introns, and about 28% of subfamily I members consist of less than 4 introns. For this reason, the two subfamilies were used to simulate intron gain and loss events, respectively. Furthermore, a new model of intron position distribution was established in current study to explore whether the evolution of multi-gene families resulted from the diversity of gene structure. Finally, RNA-seq data were used to investigate the expression profiles ofGmGELPgene under different tissues and multiple abiotic stress treatments. Subsequently, 7 stress-responsiveGmGELPgenes were selected to verify their expression levels by RT-qPCR, the results were consistent with RNA-seq data. Among 7GmGELPgenes,GmGELP28was selected for further study owing to clear responses to drought, salt and ABA treatments. TransgenicArabidopsis thalianaand soybean plants showed drought and salt tolerant phenotype. Overexpression ofGmGELP28resulted in the changes of several physiological indicators, which allowed plants to adapt adverse conditions. In all,GmGELP28is a potential candidate gene for improving the salinity and drought tolerance of soybean.