Evolution and expression analysis of starch synthase III and IV in rice

Abstract

Plants contain at least five subfamilies of starch synthases, granule bound starch synthase (GBSS) and starch synthases I, II, III, and IV (SSI, SSII, SSIII, SSIV). In this work, two members of SSIII and SSIV, respectively, were cloned and designated OsSSIII-1/-2 and OsSSIV-1/-2 in rice. Together with six other previously reported genes, the SS gene family in rice therefore is known to be duplicated and to comprise ten SS genes distributed among the five subfamilies. The starch synthase activity of each SS was confirmed by expression and enzyme activity assay in E. coli. Expression profile analysis with reverse transcription-PCR, western blotting and zymogram, indicates that OsSSIII-2 and OsSSIV-1 are mainly expressed in endosperm, while OsSSIII-1 and OsSSIV-2 are mainly expressed in the leaves. With a similar pattern of genes encoding other enzymes for starch synthesis, (such as GBSS, SSII, ADP-glucose pyrophosphorylases, and branching enzymes), it is suggested that two divergent groups of these genes should be classified in rice. Group I genes are preferentially expressed in the endosperm and function on storage starch synthesis. Group II genes are mainly expressed in leaves and some of them in the early developing endosperm, and function on transient starch synthesis in rice.

Functional Interactions between Starch Synthase III and Isoamylase-Type Starch-Debranching Enzyme in Maize Endosperm

“…SSIII contains a highly conserved N-terminal extension beyond the catalytic region, referred to the SSIII-homology domain (SSIIIHD; Gao et al, 1998;Li et al, 2003;Ral et al, 2004;Dian et al, 2005). This domain has been implicated in binding both to starch and to other proteins that are active in starch biosynthesis (Hennen-Bierwagen et al, 2009;Wayllace et al, 2010).…”

Spatiotemporal Profiling of Starch Biosynthesis and Degradation in the Developing Barley Grain

“…A full-length cDNA for SSI (Gubler et al, 2000) and a partial cDNA for SSIIa were recovered. The EST database screen also identified SSIIb (sharing 71.6% identity with barley SSIIa), SSIIIa (91.8% nucleotide identity with wheat SSIII; Li et al, 2000) and SSIIIb (79.1% identity with wheat SSIII and 91.0% identity with rice SSIII; Dian et al, 2005), and a partial SSIV sequence sharing 97.4% identity with wheat SSIV (GenBank accession no. AAK97773).…”

Identification of QTLs for resistant starch and total alkaloid content in brown and polished rice

“…It would be of greater value for our study to investigate the RS locations on chromosome 7, which would be different from Yang et al (2012), who mapped RS locus to chromosome 2. This QTL cluster is probably similar to a truncated starch synthase II-3 (SSII-3) gene on chromosome 7 (Dian et al, 2005). Gelatinization temperature was controlled by the ALK gene, which encodes a putative soluble starch synthase II-3 (Gao et al, 2011).…”