Mutations of OsPLDa1 Increase Lysophospholipid Content and Enhance Cooking and Eating Quality in Rice

Abstract

Phospholipids belong to a significant class of lipids and comprise ~10% of total lipids in rice grains. Lysophospholipid (LPL) is derived from the hydrolysis of phospholipids and plays an important role in rice grain quality. Our previous study demonstrated that mutations in a phospholipase D gene (<i>OsPLDα1</i>) significantly altered lipid metabolites and reduced phytic acid content. In the present study, the effect of two <i>ospldα1</i> mutations on LPL and other physicochemical prosperities of brown rice was further investigated, with the aim of assessing the overall importance of <i>ospldα1</i> mutations in rice grain quality. Metabolite profiling revealed a ~15% increase in LPL level in both <i>ospldα1</i> mutants as compared with their wild-type (WT) parent. Both <i>ospldα1</i> mutations significantly lowered the apparent amylose content in brown rice flour (~1.9%) and altered viscosity profiles with significantly increased breakdown (+12.4%) and significantly reduced setback viscosity (-6.2%). Moreover, both <i>ospldα1</i> mutations significantly lowered the gelatinization onset, peak temperature and retrogradation percentage of brown rice flour. This study demonstrated that OsPLDα1 plays a crucial role in rice grain quality and its mutation could, in general, improve the cooking and eating quality and nourishment of brown rice.