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

Abstract

Leaf-chewing insects are important pests that cause yield loss and reduce seed quality in soybeans (Glycine max). 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, Glyma.07g110300 (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, Agrobacterium-mediated transformation introduced the CRISPR/Cas9 expression vector into the soybean cultivar Tianlong No. 1 to generate Glyma.07g110300-gene mutants. We obtained two novel types of mutations, a 33-bp deletion and a single-bp insertion in the GmUGT coding region, which resulted in an enhanced resistance to Helicoverpa armigera and Spodoptera litura. Additionally, overexpressing GmUGT produced soybean varieties that were more sensitive to H. armigera and S. litura. Both mutant and overexpressing lines exhibited no obvious phenotypic changes. The difference in metabolites and gene expression suggested that GmUGT 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 GmUGT gene in the ugt72b1 mutant of Arabidopsis substantially rescued the phenotype of H. armigera resistance in the atugt72b1 mutant. Our study presents a strategy for increasing resistance against leaf-chewing insects in soybean through CRISPR/Cas9-mediated targeted mutagenesis of the UGT genes.

Flavonoids: Recent Advances and Applications in Crop Breeding

“…A 33-bp deletion and a single-bp insertion in the GmUGT coding domain increased resistance to Cotton bollworm (Helicoverpa armigera) and Tobacco cutworm (Spodoptera litura). Furthermore, GmUGT overexpression made soybean species susceptible to H. armigera and S. litura [109].…”

Dynamic regulation of phenylpropanoid pathway metabolites in modulating sorghum defense against fall armyworm

“…Flavonoids, a wide group of secondary metabolites, which include six major groups: chalcones, flavones, flavonols, flavandiols, anthocyanins, and the condensed tannins are derived from phenylalanine and malonyl-coenzyme A (Panche et al, 2016). Recently, flavonoids have also been found effective against aphids and chewing type insects (Morkunas et al, 2016;Kariyat et al, 2019;Zogli et al, 2020;Stec et al, 2021;Zhang et al, 2022). Moreover, flavonoids act as non-enzymatic antioxidants to suppress ROS generation and protects plants against ROS auto-toxicity (Bernards and Båstrup-Spohr, 2008;Baskar et al, 2018).…”

Genome-wide identification, characterization, and expression analysis of UDP-glycosyltransferase genes associated with secondary metabolism in alfalfa (Medicago sativa L.)

“…Currently, many UGT gene families have been identified in several crops and plant species at the whole genome-wide level, such as wheat ( Triticum aestivum ) ( He et al, 2018 ), soybean ( Glycine max) ( Yano et al, 2018 ), rice ( Oryza sativa ) ( Dong et al, 2020 ), and Arabidopsis thaliana ( Chen T. T. et al, 2020 ). Meanwhile, the sophisticated roles of plant hormone regulation, biotic and abiotic stress adaptation, yield and quality enhancement, and secondary metabolism adjustment, that UGTs played, have also been highlighted ( Mohnike et al, 2021 ; Kurze et al, 2022 ; Wang et al, 2022 ; Zhang et al, 2022 ).…”