Comparative Metabolome and Transcriptome Analysis Reveals the Possible Roles of Rice Phospholipase A Genes in the Accumulation of Oil in Grains

The phospholipase A (<i>PLA</i>) gene family plays a crucial role in the regulation of plant growth, development and stress response. Although <i>PLA</i> genes have been identified in various plant species, their specific functions and characteristics in oil quality formation of rice grains (<i>Oryza sativa</i> L.) have not been studied yet. Here, we identified and characterized 35 rice <i>PLA</i> genes, which were divided into three subgroups based on gene structures and phylogenetic relationships. These genes are distributed unevenly across 11 rice chromosomes. The promoter sequence of rice <i>PLAs</i> contain multiple plant hormones and stress-related elements. Gene expression analyses in various tissues and under stress conditions indicated that <i>PLAs</i> may be involved in rice growth, development and stress response. In addition, metabolomics, transcriptomics and qRT-PCR analyses between two rice varieties Guang8B (G8B, high oil content) and YueFengB (YFB, low oil content) revealed that the different expressional levels of rice <i>PLA</i> genes were closely related to the differences in the oil content between 'G8B' and 'YFB' grains. The findings of this study provide potential novel insights into the molecular information of the phospholipase A gene family in rice, and underscore the potential functions of <i>PLA</i> genes in rice oil content accumulation, providing valuable resources for future genetic improvement and breeding strategies.