AUTHOR=Zhou Heng , Wang Yi , Zhang Yihao , Xie Yijing , Nadeem Hasan , Tang Canming 

TITLE=Flagellin C decreases the expression of the Gossypium hirsutum cation/proton exchanger 3 gene to promote calcium ion, hydrogen peroxide, and nitric oxide and synergistically regulate the resistance of cotton to Verticillium wilt

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.969506

DOI=10.3389/fpls.2022.969506

ISSN=1664-462X

ABSTRACT=<p>To date, no ideal effective method for controlling Verticillium wilt in upland cotton (<italic>Gossypium hirsutum</italic>) has been defined. The purpose of this study was to determine the effects and mechanism through which flagellin C (<italic>FLiC</italic>) regulates the <italic>Gossypium hirsutum</italic> cation/proton exchanger 3 gene (<italic>GhCAX3</italic>), induces plant immunity, and increases resistance to Verticillium wilt. The FLiC gene was cloned from an endophytic bacterium (<italic>Pseudomonas</italic>) isolated from roots of the upland cotton cultivar Zhongmiansuo 41. The biocontrol effects of FLiC purified <italic>in vitro</italic> on resistant and susceptible upland cotton cultivars were 47.50 and 32.42%, respectively. FLiC induced a hypersensitive response (HR) in leaves of tobacco and immune responses in upland cotton. Transcriptome data showed that treatment with FLiC significantly enriched the calcium antiporter activity-associated disease-resistant metabolic pathway in seedlings. Moreover, FLiC downregulated <italic>GhCAX3</italic> expression to increase intracellular calcium ion (Ca<sup>2+</sup>) content and stimulate increases in the intracellular hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) and nitric oxide (NO) contents. The coordinated regulation of Ca<sup>2+</sup>, H<sub>2</sub>O<sub>2</sub>, and NO enhanced cotton resistance to Verticillium wilt. Furthermore, transgenic <italic>Arabidopsis</italic> plants overexpressing <italic>FLiC</italic> showed significantly improved resistance to Verticillium wilt. <italic>FLiC</italic> may be used as a resistance gene and a regulator to improve resistance to <italic>Verticillium dahliae</italic> (VD) in upland cotton.</p>