Cloning and functional identification of PeWRKY41 from Populus × euramericana

Abstract

Poplar is an important greening and economic tree species in China while damage caused by diseases and herbivorous insects seriously restricts its widespread planting. WRKYs play an important role in the response to biotic and abiotic stresses, but the defense mechanisms induced by poplar WRKY to protect the trees from herbivorous insects remain unclear. In this study, PeWRKY41 was cloned and its function was identified, aiming to provide guidance for producing salt-resistant and insect-resistant poplars. The results showed that the PeWRKY41 (1029 bp) encoded a nuclear-localized protein belonging to class III WRKY subfamily. The promoter region of PeWRKY41 contained several anti-stress-related cis-active elements that respond to the stress induced by ETH, MeJA, SA and NaCl. At the PeWRKY41-binding sites, the most significantly enriched motifs were W-box elements. Casein kinase interacts with PeWRKY41. Overexpression of PeWRKY41 improved the insect resistance and salt tolerance of transgenic Populus alba×Populus tremula var. glandulosa (84 K). A transcriptome analysis of showed that stress-resistance genes (protein kinase, berberine bridge enzyme, peroxidase, chitinase, etc.) were significantly upregulated, with the differentially expressed genes occurring in pathways related to biotic and abiotic stress defenses, such as flavonoid/flavonol biosynthesis, terpenoid backbone synthesis, phenylpropanoid biosynthesis, etc. The study provides references for the generation of stress-resistant poplars with potentially economic benefit.