Engineering high amylose and resistant starch in maize by CRISPR/Cas9-mediated editing of starch branching enzymes  

作　　者：Mingzheng Ma Shanqiu Sun Jinjie Zhu Xiantao Qi Gaoke Li Jianguang Hu Chuanxiao Xie Changlin Liu 

机构地区：[1]State Key Laboratory of Crop Gene Resources and Breeding,Institute of Crop Sciences,Chinese Academy of Agricultural Sciences,Beijing 100081,China [2]Hainan Yazhou Bay Seed Lab,Sanya 572024,Hainan,China [3]Anhui Agricultural University,Hefei 230036,Anhui,China [4]Crops Research Institute,Guangdong Academy of Agricultural Sciences,Guangzhou 510640,Guangdong,China

出　　处：《The Crop Journal》2024年第4期1252-1258,共7页作物学报（英文版）

基　　金：supported by the National Key Research and Development Program of China(2023YFD1202901);the China Agriculture Research System of MOF and MARA(CARS-02-06);the Key Area Research and Development Program of Guangdong Province(2018B020202008).

摘　　要：To improve the amylose content(AC)and resistant starch content(RSC)of maize kernel starch,we employed the CRISPR/Cas9 system to create mutants of starch branching enzyme I(SBEI)and starch branching enzyme IIb(SBEIIb).A frameshift mutation in SBEI(E1,a nucleotide insertion in exon 6)led to plants with higher RSC(1.07%),lower hundred-kernel weight(HKW,24.71±0.14 g),and lower plant height(PH,218.50±9.42 cm)compared to the wild type(WT).Like the WT,E1 kernel starch had irregular,polygonal shapes with sharp edges.A frameshift mutation in SBEIIb(E2,a four-nucleotide deletion in exon 8)led to higher AC(53.48%)and higher RSC(26.93%)than that for the WT.E2 kernel starch was significantly different from the WT regarding granule morphology,chain length distribution pattern,X-ray diffraction pattern,and thermal characteristics;the starch granules were more irregular in shape and comprised typical B-type crystals.Mutating SBEI and SBEIIb(E12)had a synergistic effect on RSC,HKW,PH,starch properties,and starch biosynthesis-associated gene expression.SBEIIa,SS1,SSIIa,SSIIIa,and SSIIIb were upregulated in E12 endosperm compared to WT endosperm.This study lays the foundation for rapidly improving the starch properties of elite maize lines.

关 键 词：MAIZE Gene editing Starch branching enzyme I Starch branching enzyme IIb 

分 类 号：S513[农业科学—作物学]