Soybean CALCIUM-DEPENDENT PROTEIN KINASE17 Positively Regulates Plant Resistance to Common Cutworm ( Spodoptera litura Fabricius).

Soybean is frequently attacked by herbivorous pests throughout the growth period. Exploring anti-insect genes to improve insect resistance in soybean is an important soybean breeding goal. Here, we cloned and characterized the gene for a quantitative trait locus (QTL) related to insect resistance, , which encodes CALCIUM-DEPENDENT PROTEIN KINASE17 () in soybean. The pairwise sequence alignment analysis revealed that the presumed protein of shares 52.06% similarity with that of , a known negative regulatory gene of insect resistance in soybean. Ectopic expression of and restored the phenotypes of the Arabidopsis insect-susceptible mutant and insect-resistant mutant , respectively. Moreover, transgenic hairy roots of the soybean cultivar Jack were generated by -mediated transformation. Overexpression of increased soybean hairy root resistance to common cutworm (CCW), while RNA interference of the gene decreased soybean hairy root resistance to CCW. Sequencing data from the cultivated and wild soybeans were used to analyze the genetic diversity of . This gene was subjected to domestication selection. Six and seven haplotypes (Haps) were identified in cultivated and wild soybeans, respectively. The resistance Hap1 is not widely used in cultivated soybeans and is mainly distributed at low latitudes. Accessions with resistance haplotypes of the and genes showed high resistance to CCW. Altogether, we revealed a novel positive regulatory insect resistance gene, , which may further improve insect resistance in soybean.