The impact of the indica rice SSIIa allele on the apparent high amylose starch from rice grain with downregulated japonica SBEIIb.

The impact of the indica rice SSIIa allele on the apparent high amylose starch from rice grain with downregulated japonica SBEIIb.
Theor Appl Genet. 2020 Jul 10;:
Authors: Luo J, Butardo VM, Yang Q, Konik-Rose C, Colgrave ML, Millar A, Jobling SA, Li Z
Abstract
KEY MESSAGE: Catalytically active indica SSIIa allele in high amylose rice with down-regulated japonica SBEIIb can increase starch content and modify the starch structure and properties without changing its amylose content. Rice (Oryza sativa) genotypes with inactive starch synthase IIa (SSIIa) with recessive variants of starch branching enzyme IIb (SBEIIb) exhibit a range of alterations in grain phenotype, starch granule morphology, starch granule bound proteins, starch structure, and functional properties. However, the interactions between the two enzymes have not been thoroughly investigated yet. We analysed recombinant rice lines having down-regulated SBEIIb expression (SBEIIbDR) with either indica or japonica type SSIIa (SSIIaind or SSIIajap). In SBEIIbDR rice starch granules, the increased abundance of two protein bands (SSI and SSIIa) was found with eight additional protein bands not generally associated with starch granules. The amount of SSIIa was higher in SSIIaindSBEIIbDR than SSIIajapSBEIIbDR, which indicated that indica type SSIIa, possibly in the monomer form, was extensively involved in starch biosynthesis in the SBEIIbDR endosperm. Furthermore, SSIIaindSBEIIbDR...

Source: TAG. Theoretical and Applied Genetics - July 9, 2020 Category: Genetics & Stem Cells Authors: Luo J, Butardo VM, Yang Q, Konik-Rose C, Colgrave ML, Millar A, Jobling SA, Li Z Tags: Theor Appl Genet Source Type: research