Suppression of starch synthase I (SSI) by RNA interference alters starch biosynthesis and amylopectin chain distribution in rice plants subjected to high temperature

Publication date: Available online 26 June 2019Source: The Crop JournalAuthor(s): Qian Zhao, Xiaoxia Du, Zhanyu Han, Yu Ye, Gang Pan, Muhammad-Asad-Ullah Asad, Qifa Zhou, Fangmin ChengAbstractBased on known cDNAs of rice starch synthase isoforms, we constructed dsRNA interference vectors for starch synthase I (SSI) to produce transgenic plants containing starch with a moderately high amylose content. We investigated the effect of SSI suppression on grain quality traits, starch biosynthesis, and amylopectin chain distribution in rice plants exposed to two different temperature regimes. The activities and transcripts of BEs, DBEs, and other SS isoforms were further investigated to clarify the effect of SSI suppression on these key enzymes and their specific isoforms under different temperature treatments. Suppression of SSI by RNAi altered grain starch component and amylopectin chain distribution, but it exerted only a slight effect on total starch content (%) and accumulation amount (mg kernel−1) and on starch granule morphology and particle size distribution. Under normal temperature (NT), insignificant differences in kernel weight, chalky kernel proportion, chalky degree, and starch granule morphology between SSI-RNAi line and its wild type (WT) were observed. However, amylose content (AC) level and granule-bound starch synthase (GBSS) activity in rice endosperms were markedly increased by SSI-RNAi suppression. The chalky kernel proportion and chalky degree of SSI-RNAi lin...

Source: The Crop Journal - June 27, 2019 Category: Food Science Source Type: research