Abstract
Verticillium wilt, mainly caused by a soil-inhabiting fungus Verticillium dahliae, can seriously reduce the yield and quality of cotton. The complex mechanism underlying cotton resistance to Verticillium wilt remains largely unknown. In plants, reactive oxygen species (ROS) mediated by Rbohs is one of the earliest responses of plants to biotic and abiotic stresses. In our previous study, we performed a time-course phospho-proteomic analysis of roots of resistant and susceptible cotton varieties in response to V. dahliae, and found early differentially expressed protein burst oxidase homolog protein D (GhRbohD). However, the role of GhRbohD-mediated ROS in cotton defense against V. dahliae needs further investigation. In this study, we analyzed the function of GhRbohD-mediated resistance of cotton against V. dahliae in vitro and in vivo. Bioinformatics analysis showed that GhRbohD possessed the conservative structural attributes of Rbohs family, 12 members of RbohD out of 57 Rbohs in cotton. The expression of GhRbohD was significantly upregulated after V. dahliae inoculation, peaking at 6 hpi, and the phosphorylation level was also increased. A VIGS test demonstrated that ROS production, NO, H2O2 and Ca2+ contents of GhRbohD-silenced cotton plants were significantly reduced, and lignin synthesis and callose accumulation were damaged, important reasons for the impairment of GhRbohD-silenced cotton’s defense against V. dahliae. The expression levels of resistance-related genes were downregulated in GhRbohD-silenced cotton by qRT-PCR, mainly involving the lignin metabolism pathway and the jasmonic acid signaling pathway. However, overexpression of GhRbohD enhanced resistance of transgenic Arabidopsis to V. dahliae challenge. Furthermore, Y2H assays were applied to find that GhPBL9 and GhRPL12C may interact with GhRbohD. These results strongly support that GhRbohD activates ROS production to positively regulate the resistance of plants against V. dahliae.
Highlights
The results showed that the expression level of of GhRbohD gene was upregulated rapidly and increased significantly after pathogen inGhRbohD gene was upregulated rapidly and increased significantly after pathogen infection, fection, especially at 6 hpi, indicating that this gene may play an important role in the especially at 6 hpi, indicating that this gene may play an important role in the response response of cotton to the stress of V. dahliae (Figure 2C)
Verticillium wilt of cotton caused by V. dahliae remains a heavy hindrance to cotton production, the main reason being lack of understanding of the mechanisms of effectively utilizing molecular and genetic engineering techniques to further develop resistant cultivars [6,7]
The expression level of GhRbohD gene was significantly increased when plants were infected with pathogen at 6 hpi, with upregulating of 50 times compared to the control, indicating that this gene may play an important role in the response of cotton to the stress of V. dahliae (Figure 2C)
Summary
Cotton Verticillium wilt is one of the main dangerous diseases globally, which poses a serious threat to the sustainable development of cotton production [3,4,5,6]. Verticillium wilt of cotton is a kind of soil-borne vascular bundle disease caused by Verticillium dahliae, which can cause vessel blockage, leaf yellowing and wilting, and even plant death, mainly resulting in yield and fiber quality loss in cotton [4,7]. It is very difficult to obtain Verticillium wilt disease-resistant cotton varieties by traditional breeding methods. With the development of genetics, molecular biology and genetic engineering, these methods will accelerate progress in the resistance of plants to Verticillium wilt [1]. Further understanding is still needed of the key genes in the resistance mechanism and regulation mechanism of cotton against Verticillium wilt [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
