Mutations in VMK1, a mitogen-activated protein kinase gene, affect microsclerotia formation and pathogenicity in Verticillium dahliae

Abstract

Verticillium dahliae is an important soil-borne fungal pathogen that causes vascular wilt diseases in a large variety of important crop plants. Due to its persistence in the soil, control of Verticillium wilt relies heavily on soil fumigation. The global ban on methyl bromide, a highly effective soil fumigant, poses an urgent need to develop alternative control measures against Verticillium wilt; and these might be more forthcoming with a better understanding of the molecular and cellular mechanisms that underpin the pathogenicity of V. dahliae. In this study, we assessed the role in growth, development, and pathogenicity of VMK1, a gene encoding a mitogen-activated protein (MAP) kinase (hence, Verticillium MAP Kinase 1). Disruption of VMK1 via Agrobacterium tumefaciens-mediated transformation, in two V. dahliae isolates, one from lettuce and the other from tomato, resulted in severely reduced virulence in diverse host plants, suggesting that VMK1 is essential for pathogenicity and that the MAP kinase-mediated signaling pathway has a conserved role in fungal pathogenicity. The vmk1 mutants also exhibited reduced conidiation and microsclerotia formation, suggesting that the gene is important for multiple cellular processes.

Verticillium wilt of olive: a case study to implement an integrated strategy to control a soil-borne pathogen

“…Indeed, disruption of VMK1 gene via Agrobacterium tumefaciens-mediated transformation (ATMT) in lettuce (Lactuca sativa L.) and tomato V. dahliae isolates provoked reduction in virulence in several host plants. Similarly, mutants of this gene showed reduced conidiation and MS formation (Rauyaree et al 2005). These studies are truly relevant in unraveling molecular mechanisms of MS morphogenesis.…”

Proteomics-based analysis reveals that Verticillium dahliae toxin induces cell death by modifying the synthesis of host proteins

“…The occlusion can be due to a physical blockage of the xylem by the pathogen or due to host defense responses that result in vessel plugging (Fradin and Thomma 2006). In recent years, some genes related to V. dahliae pathogenicity have been identified, such as a mitogen-activated protein kinase (VMK1) (Rauyaree et al 2005), a cAMP-dependent protein kinase A (VdPKAC1) (Tzima et al 2010), a glutamic acid-rich protein (VdGARP1) (Gao et al 2010) and a sucrose nonfermenting 1 gene (VdSNF1) (Tzima et al 2011). Proteins that can induce plant cell death have also been isolated from a culture supernatant of V. dahliae such as VdNEP (Wang et al 2004); however, there is still doubt whether any of these play key role in V. dahliae pathogenicity (Zhou et al 2012).…”

Conserved Regulatory Mechanisms Controlling Aflatoxin and Sterigmatocystin Biosynthesis

“…In A. nidulans and other filamentous fungi, homologs of FUS3 have been characterized (i.e. Atoui et al, 2008;Chen et al, 2004;Cousin et al, 2006;Di Petro et al, 2001;Jenczmionka et al, 2003;Mey et al, 2002;Moriwaki et al, 2007;Rauyaree et al, 2005;Ruiz-Roldman et al, 2001;Takano et al, 2000;Xu et al, 1996;). Our laboratory has shown that the A. nidulans FUS3 homolog, mpkB, controls sexual development and secondary metabolism (Paoleti et al, 2007;Atoui et al, 2008).…”