Characterization of two conserved cell death elicitor families from the Dothideomycete fungal pathogens Dothistroma septosporum and Fulvia fulva (syn. Cladosporium fulvum)

作者：Mariana Tarallo, Rebecca L. McDougal, Zhi-Yuan Chen, Yan Wang, Rosie E. Bradshaw, Carl H. Mesarich · 发表于：Frontiers in Microbiology · 年份：2022 · DOI：10.3389/fmicb.2022.964851 · 被引用次数：10 · 研究领域：Plant-Microbe Interactions and Immunity、Plant Pathogenic Bacteria Studies、Plant Disease Resistance and Genetics

Dothistroma septosporum (Ds) and Fulvia fulva (Ff; previously called Cladosporium fulvum ) are two closely related Dothideomycete fungal species that cause Dothistroma needle blight in pine and leaf mold in tomato, respectively. During host colonization, these pathogens secrete virulence factors termed effectors to promote infection. In the presence of corresponding host immune receptors, however, these effectors activate plant defenses, including a localized cell death response that halts pathogen growth. We identified two apoplastic effector protein families, Ecp20 and Ecp32, which are conserved between the two pathogens. The Ecp20 family has four paralogues in both species, while the Ecp32 family has four paralogues in D. septosporum and five in F. fulva . Both families have members that are highly expressed during host infection. Members of the Ecp20 family have predicted structural similarity to proteins with a β-barrel fold, including the Alt a 1 allergen from Alternaria alternata , while members of the Ecp32 family have predicted structural similarity to proteins with a β-trefoil fold, such as trypsin inhibitors and lectins. Using Agrobacterium tumefaciens -mediated transient transformation assays, each family member was assessed for its ability to trigger cell death in leaves of the non-host species Nicotiana benthamiana and N. tabacum . Using this approach, FfEcp20-2, DsEcp20-3, and FfEcp20-3 from the Ecp20 family, and all members from the Ecp32 family, except for th...