A time-resolved dual transcriptome analysis reveals the molecular regulating network underlying the compatible/incompatible interactions between cabbage (Brassica oleracea) and Fusarium oxysporum f. sp. conglutinans

Abstract

Cabbage Fusarium wilt (CFW) disease, caused by the soil-borne fungus Fusarium oxysporum f. sp. conglutinans (Foc), threatens cabbage production worldwide. We aimed to explore the molecular mechanism of CFW resistance and the avirulence/virulence factors of Foc. The resistant ‘96–100’ and susceptible ‘01–20’ cabbage lines were examined histologically and in RNA-seq analyses. The key differentially expressed genes (DEGs) and pathways of both the host and fungus were determined via bioinformatics databases and tools. After inoculation, Foc began to colonize in the root of 01–20 at approximately 3 dpi and almost covered the root at 9 dpi, while the colonization was inhibited in 96–100. 96,142 and 3152 unigenes were generated for cabbage and Foc, respectively, by de novo assembly. For cabbage, there were 42,056 and 37,346 DEGs in 01–20 and 96–100 at all time points. Plant-pathogen interaction (map04626) was the major enrichment pathway among the DEGs. Many NBS-LRR genes and WRKY transcription factors were identified with different expression levels between 96 and 100 and 01–20. For Foc, 977 upregulated genes and 113 downregulated genes were identified, and the pathway of ribosome (map03010) was greatly enriched. There were 1 potential effectors, 2 elicitors and 6 virulence factors with increased or decreased transcript abundance among Foc DEGs, which deserved further functional validation. The RNA-seq data were further validated by qRT-PCR. Our results provide a distinct dual transcriptomic landscape to reveal the molecular mechanisms of cabbage resistance to Foc, and expand our understanding of the interaction between plant hosts and their fungal pathogens.