Abstract: Starch is a main kind of carbohydrates and plays a vital role in energy storage. The granule-bound starch synthase (GBSS) is responsible for the synthesis of amylose. Although GBSS genes have been cloned and identified in many cultivated plants, there are only a few cases of studies on non-cultrivated plants. The present study involved qualitative and quantitative analyses on the sequence characteristics, phylogeny, and expression pattern of GBSS genes in Oryza officinalis. Phylogenetic analysis showed that the GBSS was encoded by two GBSS genes (GBSSI and GBSSII) in all species of Poaceae. In O. officinalis, the two genes shared 62% amino acid identity and displayed different expression patterns in different organs. GBSSII expression was higher in leaves than seeds, whereas GBSSI was mainly expressed in seeds, which suggests divergent spatial expression of the two genes in this wild rice.

Key words: Oryza officinalis, granule-bound starch synthase, sequence identity, expression divergence, leaf, seed