A Single‐Nucleotide Mutation in a GLUTAMATE RECEPTOR‐LIKE Gene Confers Resistance to Fusarium Wilt in <i>Gossypium hirsutum</i>

Abstract

Fusarium wilt (FW) disease of cotton, caused by the fungus <i>Fusarium oxysporum</i> f. sp. <i>vasinfectum</i> (<i>Fov</i>), causes severe losses in cotton production worldwide. Though significant advancements have been made in development of FW-resistant Upland cotton (<i>Gossypium hirsutum</i>) in resistance screening programs, the precise resistance genes and the corresponding molecular mechanisms for resistance to <i>Fov</i> remain unclear. Herein it is reported that <i>Fov7</i>, a gene unlike canonical plant disease-resistance (<i>R</i>) genes, putatively encoding a GLUTAMATE RECEPTOR-LIKE (GLR) protein, confers resistance to <i>Fov</i> race 7 in Upland cotton. A single nucleotide polymorphism (SNP) (C/A) in <i>GhGLR4.8</i>, resulting in an amino acid change (L/I), is associated with <i>Fov</i> resistance. A PCR-based DNA marker (<i>GhGLR4.8^SNP(A/C)</i> ) is developed and shown to cosegregate with the <i>Fov</i> resistance. CRISPR/Cas9-mediated knockout of <i>Fov7</i> results in cotton lines extremely susceptible to <i>Fov</i> race 7 with a loss of the ability to induce calcium influx in response to total secreted proteins (SEPs) of <i>Fov</i>. Furthermore, coinfiltration of SEPs with <i>GhGLR4.8^A</i> results in a hypersensitive response. This first report of a GLR-encoding gene that functions as an <i>R</i> gene provides a new insight into plant-pathogen interactions and a new handle to develop cotton cultivars with resistance to <i>Fov</i> race 7.