Cotton Bsr-k1 modulates lignin deposition participating in plant resistance against Verticillium dahliae and Fusarium oxysporum

Verticillium wilt and Fusarium wilt, caused by Verticillium dahliae and Fusarium oxysporum, respectively, severely restricted cotton production. It is difficult to control the damage due to large unknown about the interaction between plants and pathogens. Here, we reported the identification of cotton Bsr-k1, which was also designated as GhBsr-k1. The GhBsr-k1 was expressed in the root, stem and leaf. Silencing of GhBsr-k1 improved plant resistance to both V. dahliae and F. oxysporum. In the GhBsr-k1-silenced plants, the expression of phenylpropanoid metabolism related genes were significantly up-regulated comparing with the control, which resulting the increase of lignin deposition. Moreover, the expression level of PALs exhibited highly negative correlation with GhBsr-k1. Collectively, the results suggested GhBsr-k1 acted as a negative regulator during plant resistance against V. dahliae and F. oxysporum. The potential mechanisms beyond GhBsr-k1 in plant defense may related to the regulation of the transcript of lignin deposition genes (GhPAL2, GhPAL5).