Functional Analysis Of GhWRKY40-like And GhWRKY70 In Cotton Responsive To Verticillium Dahliae

As one of the important economic crop in the world, the production and quality of cotton has been severely affected by verticillium wilt caused by Verticillium dahliae, No effective methods and measures to control verticillium wilt have been applied in cotton production so far.Therefore, research in verticillium wilt becomes one of mainpoints in cotton molecular biology SA and JA signal pathways. play important roles in plant immunity system. It has been reported that JA signa pathway positively regulates the resistance of cotton to verticillium wilt, While SA signal pathway also been found involved in cotton resistance to verticillium wilt.Exploring mechanisms of cotton resistance to V.dahliae and characterizing the resistance genes are essential for cotton disease resistance breeding.In this study, two WRKY transcription factors in cotton are isolated and characterized. Our results demonstrate that, 1) Gh WRKY40-like and Gh WRKY70 have different tissue expression patterns.Gh WRKY40-like dominantly expressed in petals while Gh WRKY70 expressed with high level in roots, stems and leaves. 2) The expression of Gh WRKY40-like and Gh WRKY70 show different response when cotton exposed to SA and JA, The expression of Gh WRKY40-like is up-regulated by both exogenous treatments of SA and Me JA, while Gh WRKY70 is only up-regulated by SA and down-regulated by Me JA treatment. 3) Expression of Gh WRKY40-like was significantly up-regulated in cotton after inoculation with V. dahliae for 1h. However, no obvious difference in expression level of Gh WRKY70 compared to the mock. 4) Transgenic cotton plants with silencing of Gh WRKY40-like and Gh WRKY70 were generated, respectively. The results showed that knock down of Gh WRKY40-like or Gh WRKY70 both can significantly improve the resistance of cotton to V. dahlia. Meanwhile, expression levels of genes involved in SA signal pathway were up-regulated. Thereby, silencing of Gh WRKY40-like and Gh WRKY70 SA activate signaling pathway and contribute to the resistance of cotton to V. dahliae.