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

A total of 332 sugarcane leaf samples were collected from seven provinces in China during 2010 to 2013. RT-PCR was performed using the YLS111/YLS462 primers to detect the causal pathogen Sugarcane yellow leaf virus (SCYLV) causing yellow leaf disease in sugarcane. The incidence of SCYLV infection ranged from 24 to 38 % depending on geographic areas. A new primer pair (P0-R3/P0-F2) was designed to prime the amplification of a 968-nucleotide (nt) fragment from SCYLV-positive samples. The fragment contained a partial 5′ untranslated region, the complete ORF0 encoding P0, and a partial ORF1. A phylogenetic analysis of 141 P0 fragment sequences (937 nt) worldwide showed that all SCYLV isolates were clustered into eight genotypes. The 107 SCYLV isolates collected in this study were classified into three genotypes (BRA, HAW, and CHN3), of which the BRA genotype (102/107) was the most prevalent and was detected in all evaluated locations. One isolate (1/107) of genotype HAW was found in Hainan province. Four isolates (4/107) of the genotype CHN3 were observed in Guangxi, Guizhou and Hainan provinces. These findings help understand the genotypic diversity and distribution of SCYLV isolates in China.

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