Comparative genomics and expression profile of lipid biosynthesis pathway genes in Camellia sinensis

Abstract

The lipid biosynthesis pathway is directly associated with lipid content in plants. The genes involved in lipid biosynthesis of tea plant (Camellia sinensis) were identified through in-silico mining of available transcriptomic data in public domain. Seventy five homologous genes in tea were identified through comparative genomics and 56 sequences of them showed more than 50% sequence similarity with the Arabidopsis reference sequences. The expression pattern of five key genes biotin carboxylase (BC), Acyl CoA: diacylglycerol acyltransferase (DGAT), phosphatidylinositol synthase (PIS), monogalactosyldiacylglycerol synthase (MGDGS) and glycerol 3 phosphate dehydrogenase (G3PDH) were analysed through qRT-PCR in roots, leaves, flowers, and seeds of three Tocklai released tea varieties (TV1, TV17 and TV20). Relative expression analysis showed that all the five genes were highly up-regulated in the seeds compared to the other parts of the studied tea varieties. Except biotin carboxylase, other four genes showed highest expression in TV1 seeds compared to TV17 and TV20. The overall increased expression of four key lipid biosynthesis genes give an indication that TV1 seeds may contain higher lipid content than the others in this study. DGAT, PIS and G3PDH also showed upregulation in the leaves and roots of some of the studied varieties which is an indication of possible involvement of lipid biosynthesis genes in various growth and developmental processes.