Overexpression of TaWRKY14 transcription factor enhances accumulation of chlorogenic acid in Taraxacum antungense Kitag and increases its resistance to powdery mildew

Abstract

WRKY transcription factors play a critical role in metabolism and stress responses in plants, but few WRKYs have been reported in Taraxacum antungense. Here, a multiple stress-inducible gene, TaWRKY14, was isolated from T. antungense. TaWRKY14 was localized to the nuclei, and phylogenetic analysis indicated that TaWRKY14 shared the highest identity to WRKY40 in Salvia miltiorrhiza. TaWRKY14 was highly expressed in roots, and up-regulated by salt and drought stress, salicylic acid treatment and powdery mildew. TaWRKY14-overexpressing transgenic lines had higher chlorogenic acid concentration and high expression of TaPAL1. The yeast one-hybrid assay proved that TaWRKY14 bond to the W-box of proTaPAL1. Additionally, field experiments showed that TaWRKY14-overexpressing T. antungense lines have higher powdery mildew resistance than the wild-type. Our results demonstrated that TaWRKY14 can regulate CGA biosynthesis and play an important role in resistance to powdery mildew in T. antungense. TaWRKY14 transgenic T. antungense can be used for further evaluation as a new germplasm resource. We analyzed and evaluated the biological function of TaWRKY14 in Taraxacum antungense, and determined that TaWRKY14-overexpressing lines have higher chlorogenic acid concentration and stronger resistance to powdery mildew.