A SIX1 Homolog in Fusarium oxysporum f. sp. conglutinans Is Required for Full Virulence on Cabbage

PLoS One. 2016 Mar 24;11(3):e0152273. doi: 10.1371/journal.pone.0152273. eCollection 2016.

Abstract

Fusarium oxysporum is a soil-born fungus that induces wilt and root rot on a variety of plants. F. oxysporum f. sp. conglutinans (Foc) can cause wilt disease on cabbage. This study showed that a homolog of SIX1 protein in the Arabidopsis infecting isolate Fo5176 (Fo5176-SIX1) had four isoforms in the conidia of Foc by proteomic analysis. Thus, we analyzed the roles of protein Foc-SIX1. Gene expression analysis showed that, compared to the expression in mycelia, dramatically altered expression of Foc-SIX1 could be detected after infecting cabbages, and Foc-SIX1 was highly expressed in conidia under axenic culture condition. Furthermore, we knocked out the Foc-SIX1 gene and found that Foc-ΔSIX1 mutants had significantly reduced virulence compared with wild type isolate, and full virulence was restored by complementation of Foc-ΔSIX1 mutants with Foc-SIX1. Thus, we concluded that SIX1 in Foc was required for full virulence on cabbage. We also complemented Foc-ΔSIX1 with SIX1 gene in F. oxysporum f. sp. lycopersici (Fol) and found Foc-ΔSIX1::Fol-SIX1 mutants did not affect the virulence of Foc-ΔSIX1. The results confirmed that Fol-SIX1 was not capable of replacing the role of Foc-SIX1 in Foc on the disease symptom development of cabbage. The roles of Fol-SIX1 on virulence might rely on host specificity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brassica / microbiology*
  • Fungal Proteins / genetics*
  • Fusarium / genetics
  • Fusarium / pathogenicity*
  • Gene Deletion
  • Genes, Fungal
  • Phylogeny
  • Virulence / genetics*

Substances

  • Fungal Proteins

Grants and funding

This work was funded by the National Natural Science Foundation of China (31272003), [http://www.nsfc.gov.cn/], to YHY; National Key Technology R&D Program (2012BAD19B06), [http://program.most.gov.cn/], to BYX; National Staple Vegetable Industry Technology System Construction Project (CARS-25-B-01), to BYX; Special Fund for Agro-scientific Research in the Public Interest (200903049-04), to BYX. The funders had roles in study design, data collection and analysis, decision to publish and preparation of the manuscript.