A novel GLYCEROPHOSPHODIESTER PHOSPHODIESTERASE 13 is involved in the Phosphate starvation-induced lipid remodeling in rice

Phosphorus (P) is one of the most vital macronutrient determinants in plant development and productivity. However, the bioavailability of inorganic phosphate (Pi), the only form that plants can assimilate, is limited in the soil, thus significantly affecting plant development. Plants have adopted various specialized strategies to modify their morphological, physiological, and biochemical properties for better adaptation to Pi deficiency conditions. GLYCEROPHOSPHODIESTER PHOSPHODIESTERASES (GDPDs), generally known as phospholipid remodeling proteins, have been suggested to play essential roles in maintaining phosphate homeostasis. The previous genome-wide association studies (GWAS) in a Vietnamese rice collection led to the discovery of a robust QTL named qRST9.14 associating with the phosphate adaption in rice, in which OsGDPD13 is located within this locus. Interestingly, we discovered an absence of OsGDPD13 from the Indica reference genome. A subcellular localization study showed that the GDPD13 protein localizes to the plasma membrane, cytoplasmic speckles, and plasmodesmata. The osgdpd13 knockout mutant was generated in the Japonica cv Kitaake background to characterize its function. Phenotypic analysis indicated that mutation of OsGDPD13 significantly lowered crown root number and reduced the plant height under Pi deficient condition. Moreover, osgdpd13 lines reduce the capability to degrade total phospholipids compared to the wild type under Pi starvation conditions. This finding suggests the involvement of the OsGDPD13 gene in rice growth and the Phosphate starvation-induced lipid remodeling under P deficiency. This work will provide valuable information for developing crop plants with higher Phosphate use efficiency.