Transcriptome reveals Gafmt-1 and Gadlc-1-5 play positive roles in cotton resistance to Verticillium wilt

Both Gafmt-1 and Gadlc-1-5 from Gossypium arboreum respond to Verticillium dahilae infection in Gossypium hirsutum and may play positive roles in Verticillium wilt resistance via the salicylic acid pathway. Verticillium wilt (VW) caused by Verticillium dahliae is one of the most destructive diseases affecting cotton production and quality worldwide. Numerous resistance genes against the disease from tetraploid cultivated cotton (2n = 4x = AADD = 52) have been cloned and functionally analyzed to attempt to develop resistant varieties. However, VW continues to pose a significant threat to global cotton production due to the lack of cost-effective resistance genes to balance resistance and yield. Resistance genes from diploid cotton species such as Gossypium arboreum (2n = 2x = AA = 26) remain largely untapped, and their functions are unknown. Here, a resistant G. hirsutum-G. arboreum introgression line, DM10781, was employed to mine new resistance genes against V. dahliae from the diploid cotton species. We performed time-course transcriptome analysis on the RNA-seq data at 0, 4, 12, 24, 48, and 96 h post-inoculation. Weighted gene co-expression network analysis showed that nine differentially expressed genes (DEGs) caused by disease resistance have been identified. Among them, seven genes were found on the introgression segments from G. arboreum and suffered from virus-induced gene silencing in DM10781. Out of them, two genes were further overexpressing in Arabidopsis. The results indicated the two genes of Gafmt-1 and Gadlc-1-5 played positive roles in both cotton and Arabidopsis. Our study demonstrates that G. arboreum has the resistance genes to VW and can be used in future disease-resistance breeding, providing insights into the resistance of Gafmt-1 and Gadlc-1-5 against VW in cotton.