AUTHOR=Zhang Yongxing , Guo Wei , Chen Limiao , Shen Xinjie , Yang Hongli , Fang Yisheng , Ouyang Wenqi , Mai Sihua , Chen Haifeng , Chen Shuilian , Hao Qingnan , Yuan Songli , Zhang Chanjuan , Huang Yi , Shan Zhihui , Yang Zhonglu , Qiu Dezhen , Zhou Xinan , Cao Dong , Li Xia , Jiao Yongqing 

TITLE=CRISPR/Cas9-Mediated Targeted Mutagenesis of GmUGT Enhanced Soybean Resistance Against Leaf-Chewing Insects Through Flavonoids Biosynthesis

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.802716

DOI=10.3389/fpls.2022.802716

ISSN=1664-462X

ABSTRACT=<p>Leaf-chewing insects are important pests that cause yield loss and reduce seed quality in soybeans (<italic>Glycine max</italic>). Breeding soybean varieties that are resistant to leaf-chewing insects can minimize the need for insecticide use and reduce yield loss. The marker gene for QTL-M, <italic>Glyma.07g110300</italic> (LOC100775351) that encodes a UDP-glycosyltransferase (UGT) is the major determinant of resistance against leaf-chewing insects in soybean; it exhibits a loss of function in insect-resistant soybean germplasms. In this study, <italic>Agrobacterium</italic>-mediated transformation introduced the CRISPR/Cas9 expression vector into the soybean cultivar Tianlong No. 1 to generate <italic>Glyma.07g110300-</italic>gene mutants. We obtained two novel types of mutations, a 33-bp deletion and a single-bp insertion in the <italic>GmUGT</italic> coding region, which resulted in an enhanced resistance to <italic>Helicoverpa armigera</italic> and <italic>Spodoptera litura</italic>. Additionally, overexpressing <italic>GmUGT</italic> produced soybean varieties that were more sensitive to <italic>H</italic>. <italic>armigera</italic> and <italic>S. litura</italic>. Both mutant and overexpressing lines exhibited no obvious phenotypic changes. The difference in metabolites and gene expression suggested that <italic>GmUGT</italic> is involved in imparting resistance to leaf-chewing insects by altering the flavonoid content and expression patterns of genes related to flavonoid biosynthesis and defense. Furthermore, ectopic expression of the <italic>GmUGT</italic> gene in the <italic>ugt72b1</italic> mutant of <italic>Arabidopsis</italic> substantially rescued the phenotype of <italic>H. armigera</italic> resistance in the <italic>atugt72b1</italic> mutant. Our study presents a strategy for increasing resistance against leaf-chewing insects in soybean through CRISPR/Cas9-mediated targeted mutagenesis of the <italic>UGT</italic> genes.</p>