Core effectorome of Fusarium oxysporum f. sp. conglutinans deciphered using a multiomics method exhibits diverse roles following infection in cabbage

Fusarium oxysporum f. sp. conglutinans (Focn), the causal agent of Fusarium wilt of cole crops such as cabbage, causes significant yield losses worldwide. However, the molecular mechanisms underlying Focn-mediated host susceptibility remain largely unexplored. Here, we presented the chromosome-level genome assembly of the Focn race 1 strain FGL03-6 via a single-molecule real-time sequencing platform, resequenced the genomes of 23 strains belonging to races 1 and 2, and performed genome-wide identification of Focn effectors using multiomics data generated from the Focn-cabbage interaction. In total, a core set of 14 candidate effectors were identified, among which 11 induced pronounced programmed cell death (PCD) in different cabbage lines, whereas only 1 candidate triggered partial cell death on the leaves of Nicotiana benthamiana, indicating that natural host cabbage is ideal for functional study of Focn effectors compared with N. benthamiana. In addition, we found that 8 PCD-inducing effectors can trigger cell death in highly resistant (HR) cabbage line 96-100, among which 2 can also trigger cell death in HR line BI-16 and moderately resistant line 084, separately, whereas 2 effectors induced PCD exclusively in the highly susceptible line 79-156, suggesting that different effectors might be exploited when Focn invades cabbage lines with distinct genetic backgrounds. Pathogenicity assays showed that Focn-EF7 knockout mutants exhibited enhanced virulence, whereas Focn-EF2 knockout mutants displayed reduced virulence. Our findings demonstrate that Focn invades host plants using diverse effector proteins, and the newly identified core effectorome provides a solid basis for understanding the molecular interactions between Focn and cabbage and for facilitating the development of strategies for effective disease control.