Pyrenophora tritici–repentis in Tunisia : race structure and effector genes

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creativework.keywords - en
Phytopathogenic fungi
Champignons phytopathogènes
Haplotypes
creativework.keywords - fr
Haplotypes
Blé--Maladies et fléaux
Wheat--Diseases and pests
dc.contributor.author
Kamel, Sana
Cherif, Mejda
Hafez, Mohamed
Despins, Therese
Aboukhaddour, Reem
dc.date.accepted
2019-11-07
dc.date.accessioned
2024-10-07T18:00:00Z
dc.date.available
2024-10-07T18:00:00Z
dc.date.issued
2019-12-18
dc.date.submitted
2019-09-10
dc.description.abstract - en
Tan spot is a destructive foliar wheat disease worldwide and caused by the ascomycete fungus Pyrenophora tritici–repentis (Ptr); it has become more frequent in Tunisia over the last decade. In this study, the virulence of 73 single-spore isolates, collected from durum and bread wheat fields during 2017–2018 growing season, was evaluated on four differential wheat genotypes. This was followed by polymerase chain reaction tests with specific primers for the effector genes ToxA, ToxB, and toxb (ToxB-homolog). Sequence analysis to validate the identity of the amplified genes was followed, and ToxA amplicons from a subset of 22 isolates were analyzed to determine its haplotype identity. Ptr isolates from Tunisia were grouped in races 2, 4, 5, and 7, and 44% of the tested isolates did not fit under any known race, and were denoted here as atypical. These atypical isolates induced the same symptoms as race 7 isolates, extensive necrosis, and chlorosis on susceptible genotypes, but lacked the ToxA gene. ToxA is the only identified necrosis-inducing effector in Ptr, and was amplified in 51% of tested isolates, and shared identical sequence to previously identified haplotype (H15). ToxB and its homolog toxb were present in 97% and 93% of tested isolates, respectively. Ptr in Tunisia lacked Ptr ToxC activity, and none of the tested isolates induced the specific symptoms of that effector. Race 7 and the atypical isolates dominated the Tunisian Ptr population, while races 2, 4, and 5 were found at low percentages. In conclusion, ToxB and its homolog were the most dominant genes in Ptr from Tunisia, and the majority of the isolates induced necrosis and chlorosis on Ptr ToxA and Ptr ToxB susceptible wheat genotypes. However, only about half of that necrosis can be attributed to ToxA presence, this result necessitates further research to investigate the prevalence of additional necrotic effector(s). Terminology: in this paper, Pyrenophora tritici–repentis abbreviated as Ptr, the effectors are referred to by Ptr ToxA, Ptr ToxB and Ptr ToxC, and the genes coding for them are written in italic as ToxA, ToxB, and ToxC, respectively.
dc.identifier.citation
Kamel, S., Cherif, M., Hafez, M., Despins, T., & Aboukhaddour, R. (2019). Pyrenophora tritici–repentis in Tunisia : race structure and effector genes. Frontiers in Plant Science, 10, Article 1562. https://doi.org/10.3389/fpls.2019.01562
dc.identifier.doi
https://doi.org/10.3389/fpls.2019.01562
dc.identifier.issn
1664-462X
dc.identifier.uri
https://science-ouverte.canada.ca/handle/123456789/3016
dc.language.iso
en
dc.publisher
Frontiers Media S.A.
dc.rights - en
Creative Commons Attribution 4.0 International (CC BY 4.0)
dc.rights - fr
Creative Commons Attribution 4.0 International (CC BY 4.0)
dc.rights.openaccesslevel - en
Gold
dc.rights.openaccesslevel - fr
Or
dc.rights.uri - en
https://creativecommons.org/licenses/by/4.0/
dc.rights.uri - fr
https://creativecommons.org/licenses/by/4.0/deed.fr
dc.subject - en
Nature and environment
Agriculture
dc.subject - fr
Nature et environnement
Agriculture
dc.subject.en - en
Nature and environment
Agriculture
dc.subject.fr - fr
Nature et environnement
Agriculture
dc.title - en
Pyrenophora tritici–repentis in Tunisia : race structure and effector genes
dc.type - en
Article
dc.type - fr
Article
local.acceptedmanuscript.articlenum
1562
local.article.journaltitle
Frontiers in Plant Science
local.article.journalvolume
10
local.pagination
1-11
local.peerreview - en
Yes
local.peerreview - fr
Oui
local.requestdoi
No
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