Characterization of an antimicrobial and phytotoxic ribonuclease secreted by the fungal wheat pathogen Zymoseptoria tritici

A - Papers appearing in refereed journals

Kettles, G. J., Bayon, C., Sparks, C. A., Canning, G., Kanyuka, K. and Rudd, J. J. 2018. Characterization of an antimicrobial and phytotoxic ribonuclease secreted by the fungal wheat pathogen Zymoseptoria tritici. New Phytologist. 217 (1), pp. 320-331.

AuthorsKettles, G. J., Bayon, C., Sparks, C. A., Canning, G., Kanyuka, K. and Rudd, J. J.
Abstract

The fungus Zymoseptoria tritici is the causal agent of Septoria Tritici Blotch (STB) disease of wheat leaves. Zymoseptoria tritici secretes many functionally uncharacterized effector proteins during infection. Here, we characterized a secreted ribonuclease (Zt6) with an unusual biphasic expression pattern.
Transient expression systems were used to characterize Zt6, and mutants thereof, in both host and non‐host plants. Cell‐free protein expression systems monitored the impact of Zt6 protein on functional ribosomes, and in vitro assays of cells treated with recombinant Zt6 determined toxicity against bacteria, yeasts and filamentous fungi.
We demonstrated that Zt6 is a functional ribonuclease and that phytotoxicity is dependent on both the presence of a 22‐amino‐acid N‐terminal ‘loop’ region and its catalytic activity. Zt6 selectively cleaves both plant and animal rRNA species, and is toxic to wheat, tobacco, bacterial and yeast cells, but not to Z. tritici itself.
Zt6 is the first Z. tritici effector demonstrated to have a likely dual functionality. The expression pattern of Zt6 and potent toxicity towards microorganisms suggest that, although it may contribute to the execution of wheat cell death, it is also likely to have an important secondary function in antimicrobial competition and niche protection.

Keywords
Year of Publication2018
JournalNew Phytologist
Journal citation217 (1), pp. 320-331
Digital Object Identifier (DOI)doi:10.1111/nph.14786
PubMed ID28895153
PubMed Central IDPMC5724701
Open accessPublished as ‘gold’ (paid) open access
Funder project or codeWheat
Designing Future Wheat (DFW) [ISPG]
DFW - Designing Future Wheat - Work package 1 (WP1) - Increased efficiency and sustainability
FunderBiotechnology and Biological Sciences Research Council
Publisher's versionKettles_et_al-2017-New_Phytologist.pdf
Output statusPublished
Publication dates
Online12 Sep 2017
Publication process dates
Accepted11 Aug 2017
Copyright licenseCC BY
PublisherWiley
Grant IDBB/J/00426X/1
BB/P016855/1
ISSN0028-646X

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