Unveiling genomic diversity of glycolipid transfer protein (GLTP) gene family in rice: The lipid connection to climate resilience

Abstract

Glycolipid transfer protein (GLTP) genes are recognized for their role in stress adaptation in animals. In this study, for the first time, seventy-four GLTP genes were identified across ten Oryza species, with each species containing 6-9 genes. These genes exhibited strong synteny and collinearity, maintaining conserved chromosomal positions across all Oryza species. Gene duplication events were frequent, accounting for 61.9 % of the GLTP genes, and their Ka/Ks ratios (<1) suggested purifying selection and evolutionary conservation. All identified genes encoded proteins with a single GLTP domain and clustered into three major clades: two containing distinct sets of GLTP genes and the third comprising ACD11-like genes. Notably, the GLTP2-miR414 regulatory module was supported by both bioinformatic predictions and experimental validation. Structural and functional analyses revealed ACD11 and GLTP3 as the most promising candidate genes for stress responses. Further, for functional validation of GLTP3 by candidate gene analysis using a rice minicore diversity panel revealed 14 significant marker-trait associations, including two markers specifically associated with malondialdehyde content-a key indicator of lipid peroxidation-under heat stress conditions. This is the first report on the GLTP genes in rice with promising leads for their utilization in stress breeding.

Keywords: ACD11 genes; Abiotic stress; GLTP genes; Gene duplication; Purifying selection; Rice (Oryza); miRNA regulation.