Characterisation of genes involved in galactolipids and sulfolipids metabolism in maize and Arabidopsis and their differential responses to phosphate deficiency.

Galactolipids (MGDG and DGDG) and sulfolipids (SQDG) are key components of plastidic membranes, and play important roles in plant development and photosynthesis. In this study, the whole families of MGD, DGD and SQD were identified in maize genome, and were designated as ZmMGD1-3, ZmDGD1-5 and ZmSQD1-5 respectively. Based on the phylogenetic analyses, maize and Arabidopsis MGDs, DGDs and SQDs were clearly divided into two major categories (Type A and Type B) along with their orthologous genes from other plant species. Under low-phosphorus condition, the expression of Type B MGD, DGD and SQD genes of maize and Arabidopsis were significantly elevated in both leaf and root tissues. The lipid analysis was also conducted, and an overall increase in non-phosphorus lipids (MGDG, DGDG and SQDG), and a decrease in phosphorus lipids (PC, PE and PA) were observed in maize leaves and roots under phosphate deficiency. Several maize MGD and SQD genes were found involved in various abiotic stress responses. These findings will help for better understanding the specific functions of MGDs, DGDs and SQDs in 18:3 plants and for the generation of improved crops adapted to phosphate starvation and other abiotic stresses.