Verticillium dahliae is a soil-borne fungal disease with a wide range of hosts. It harms major economic crops such as cotton, tomato, lettuce, and pepper, and causes serious economic losses to agricultural production. Cotton Verticillium wilt, caused by Verticillium dahliae, is one of the most important threats to cotton production. Mining Verticillium wilt resistance genes in cotton germplasm resources and analyzing their disease resistance mechanisms are of great significance for genetic improvement of cotton disease resistance and stable cotton production.
Recently, Genome Biology published an article titled "Genome-wide association analysis reveals a novel pathway mediated by a dual-TIR domain protein for pathogen resistance in cotton", analyzing the key gene GhRVD1 for resistance to Verticillium wilt and its genetic basis for resistance to Verticillium wilt. This study provides an important target for improving cotton disease resistance through biological breeding, and provides a new idea for the prevention and control of cotton Verticillium wilt.
In this study, an introgressed fragments was identified to be significantly associated with Verticillium wilt resistance in upland cotton, and it was found that GhRVD1, which encodes the intracellular nucleotide-binding site leucine-rich repeat (NLR) receptors, is the key gene for Verticillium wilt resistance. And the mutation of a few nucleotide sites of this gene in upland cotton weakens its mediated resistance to Verticillium wilt.
More importantly, GhRVD1 is the first NLR protein identified in plants with a nitrogen-terminal tandem Toll/interleukin-1 receptor (TIR) structure, whose tandem TIR structure mediates a rapid immune response by forming an inverse parallel dimer. In addition, the study also found that the nitrogen-terminal binding protein of GhRVD1, GhTIRP1, is an important switch for balancing vegetative growth and immune response in plants. It competitively binds to GhRVD1 under normal growth conditions, inhibits the formation of dimers, and then blocks the immune response mediated by it to maintain normal growth of cotton. However, under the invasion condition of Verticillium dahliae, it releases the GhRVD1 occupancy by down-regulating the expression, promotes the formation of dimers, and then activates the downstream immune response to resist the invasion of pathogenic bacteria.
Reference:
Zhang, Y., Zhang, Y., Ge, X. et al. Genome-wide association analysis reveals a novel pathway mediated by a dual-TIR domain protein for pathogen resistance in cotton. Genome Biol 24, 111 (2023). https://doi.org/10.1186/s13059-023-02950-9
