Infection of cotton seedlings and sample collection
Two-week-old seedlings of G. barbadense cv. 7124 and G. hirsutum cv. YZ1 were infected with V. dahliae conidial suspensions (1×10^6 conidia·ml-1) using a root dip inoculation method, and control plants were mock-inoculated with sterile water. Roots were harvested at 0 h, 6 h, 12 h, 24 h and 48 h post inoculation, frozen in liquid nitrogen and stored at -80°C for subsequent RNA extraction.