AUTHOR=Sun Yongwei , Jiao Guiai , Liu Zupei , Zhang Xin , Li Jingying , Guo Xiuping , Du Wenming , Du Jinlu , Francis Frédéric , Zhao Yunde , Xia Lanqin 

TITLE=Generation of High-Amylose Rice through CRISPR/Cas9-Mediated Targeted Mutagenesis of Starch Branching Enzymes

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.00298

DOI=10.3389/fpls.2017.00298

ISSN=1664-462X

ABSTRACT=<p>Cereals high in amylose content (AC) and resistant starch (RS) offer potential health benefits. Previous studies using chemical mutagenesis or RNA interference have demonstrated that starch branching enzyme (SBE) plays a major role in determining the fine structure and physical properties of starch. However, it remains a challenge to control starch branching in commercial lines. Here, we use CRISPR/Cas9 technology to generate targeted mutagenesis in <italic>SBEI</italic> and <italic>SBEIIb</italic> in rice. The frequencies of obtained homozygous or bi-allelic mutant lines with indels in <italic>SBEI</italic> and <italic>SBEIIb</italic> in T<sub>0</sub> generation were from 26.7 to 40%. Mutations in the homozygous T<sub>0</sub> lines stably transmitted to the T<sub>1</sub> generation and those in the bi-allelic lines segregated in a Mendelian fashion. Transgene-free plants carrying only the frame-shifted mutagenesis were recovered in T<sub>1</sub> generation following segregation. Whereas no obvious differences were observed between the <italic>sbeI</italic> mutants and wild type, <italic>sbeII</italic> mutants showed higher proportion of long chains presented in debranched amylopectin, significantly increased AC and RS content to as higher as 25.0 and 9.8%, respectively, and thus altered fine structure and nutritional properties of starch. Taken together, our results demonstrated for the first time the feasibility to create high-amylose rice through CRISPR/Cas9-mediated editing of <italic>SBEIIb</italic>.</p>