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

Tarallo M; McDougal RL; Chen Z; Wang Y; Bradshaw RE; Mesarich CH

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

dc.citation.volume	13
dc.contributor.author	Tarallo M
dc.contributor.author	McDougal RL
dc.contributor.author	Chen Z
dc.contributor.author	Wang Y
dc.contributor.author	Bradshaw RE
dc.contributor.author	Mesarich CH
dc.contributor.editor	Wang Y
dc.coverage.spatial	Switzerland
dc.date.accessioned	2023-12-15T01:28:12Z
dc.date.accessioned	2024-07-25T06:40:55Z
dc.date.available	2022-09-08
dc.date.available	2023-12-15T01:28:12Z
dc.date.available	2024-07-25T06:40:55Z
dc.date.issued	2022-09-08
dc.description.abstract	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 the Ds/FfEcp32-4 pair, triggered cell death in both species. This cell death was dependent on secretion of the effectors to the apoplast. In line with recognition by an extracellular immune receptor, cell death triggered by Ds/FfEcp20-3 and FfEcp32-3 was compromised in N. benthamiana silenced for BAK1 or SOBIR1, which encode extracellular co-receptors involved in transducing defense response signals following apoplastic effector recognition. We then investigated whether DsEcp20-3 and DsEcp20-4 triggered cell death in the host species Pinus radiata by directly infiltrating purified protein into pine needles. Strikingly, as in the non-host species, DsEcp20-3 triggered cell death, while DsEcp20-4 did not. Collectively, our study describes two new candidate effector families with cell death-eliciting activity from D. septosporum and F. fulva and provides evidence that members of these families are recognized by plant immune receptors.
dc.description.confidential	false
dc.format.pagination	964851-
dc.identifier.author-url	https://www.ncbi.nlm.nih.gov/pubmed/36160260
dc.identifier.citation	Tarallo M, McDougal RL, Chen Z, Wang Y, Bradshaw RE, Mesarich CH. (2022). Characterization of two conserved cell death elicitor families from the Dothideomycete fungal pathogens Dothistroma septosporum and Fulvia fulva (syn. Cladosporium fulvum).. Front Microbiol. 13. (pp. 964851-).
dc.identifier.doi	10.3389/fmicb.2022.964851
dc.identifier.eissn	1664-302X
dc.identifier.elements-type	journal-article
dc.identifier.issn	1664-302X
dc.identifier.number	964851
dc.identifier.uri	https://mro.massey.ac.nz/handle/10179/70664
dc.language	eng
dc.publisher	Frontiers Media S.A.
dc.publisher.uri	https://www.frontiersin.org/articles/10.3389/fmicb.2022.964851/full
dc.relation.isPartOf	Front Microbiol
dc.rights	(c) The author/s	en
dc.rights.license	CC BY	en
dc.rights.uri	https://creativecommons.org/licenses/by/4.0/	en
dc.subject	Dothideomycetes
dc.subject	cell death-eliciting effectors
dc.subject	immune receptors
dc.subject	plant-pathogen interactions
dc.subject	protein families
dc.subject	protein tertiary structure
dc.title	Characterization of two conserved cell death elicitor families from the Dothideomycete fungal pathogens Dothistroma septosporum and Fulvia fulva (syn. Cladosporium fulvum)
dc.type	Journal article
pubs.elements-id	457187
pubs.organisational-group	Other