LYSIN MOTIF-CONTAINING PROTEINS PLAY ROLE IN DEFENSE AGAINST VERTICILLIUM DAHLIAE IN COTTON
Lysin motif (LysM)-containing proteins are important pattern recognition receptors (PRRs) in plants, which function in the perception of microbe-associated molecular patterns (MAMPs) and in the defense against pathogenic attack. To date, the LysM genes have not been fully analyzed in cotton (Gossypium hirsutum) or effectively utilized for disease resistance.
The team of Jun Xu from Nanjing Agricultural University in China identified all LysM genes from four sequenced cotton species. These LysM genes were then classified into four groups with different structural characteristics and a variety of expression patterns in different organs and tissues when induced by chitin or Verticillium dahliae. The team then focused on three genes, Lyp1, Lyk7, and LysMe3, which showed a significant increase in expression in response to chitin signals, V. dahliae presence, and several stress-related signaling compounds.
Lyp1, Lyk7, and LysMe3 proteins were found to be localized to the plasma membrane. Silencing of their expression in cotton drastically impaired salicylic acid, jasmonic acid, and reactive oxygen species generation. The silencing also impaired defense gene activation and compromised resistance to V. dahliae.
These results indicate that Lyp1, Lyk7, and LysMe3 are important PRRs that function in the recognition of chitin signals to activate the downstream defense processes and induce cotton defense against V. dahliae.