Objective Phospholipase D (PLD) plays a crucial role in plant growth, development, and stress response. The study was conducted to explore the PLD gene family members involved in biotic and abiotic stress in rice (Oryza sativa L.) and investigate their biological functions.

Method The rice PLD family members were identified based on the rice genome database, and the protein physicochemical properties, phylogenetics, conserved motifs, and cis-acting elements of the gene family members were systematically analyzed by bioinformatics methods. The gene expression patterns of the family members under different biotic and abiotic stress conditions were analyzed through RNA-seq data, and the changes of total PLD activity under stress treatment conditions were detected.

Result The rice PLD gene family had 17 members with amino acid numbers ranging from 512 to 1115 and relative molecular weights ranging from 57.19 to 123.82 kD; The isoelectric points of these proteins were between 5.60 and 11.23. According to the phylogenetic tree, the PLD gene family was divided into four subfamilies, and there were significant differences in the number of exons among the members of different subfamilies. Chromosome localization analysis revealed that 17 PLD genes were located on 9 chromosomes. The analysis of cis-acting elements revealed that the promoter regions of PLD gene family members contained a large number of hormone responsive elements such as auxin, abscisic acid, and methyl jasmonate, as well as low temperature response, pressure defense, and anaerobic induction responsive elements; RNA-seq data analysis under biotic and abiotic stress conditions revealed that members of the PLD gene family were strongly induced by low nitrogen, ABA, and GA; In addition, enzyme activity analysis showed a significant increase of total phospholipase D activity after high salt stress and black stripe dwarf disease infection.

Conclusion A total of 17 rice PLD genes are identified, and members in the same subfamily have similar conserved motifs. The expression of PLD gene family members in rice varies in different tissues and under biotic and abiotic stress conditions. These results will provide assistance in analyzing the role and mechanism of phospholipase D family in rice growth and development, biotic and abiotic stress response.