Random T-DNA mutagenesis identifies a Cu/Zn superoxide dismutase gene as a virulence factor of Sclerotinia sclerotiorum

Liangsheng Xu; Weidong Chen

doi:10.1094/MPMI-07-12-0177-R

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Random T-DNA mutagenesis identifies a Cu/Zn superoxide dismutase gene as a virulence factor of Sclerotinia sclerotiorum

Journal article

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Random T-DNA mutagenesis identifies a Cu/Zn superoxide dismutase gene as a virulence factor of Sclerotinia sclerotiorum

Liangsheng Xu and Weidong Chen

Molecular plant-microbe interactions, Vol.26(4), pp.431-441

04/2013

DOI: https://doi.org/10.1094/MPMI-07-12-0177-R

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https://hdl.handle.net/2376/114222

PMID: 23252459

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Abstract

Ascomycota - pathogenicity

Superoxide Dismutase - genetics

DNA, Bacterial - genetics

Virulence Factors - genetics

Oxidative Stress - physiology

Ascomycota - genetics

Mutagenesis - genetics

Oxidative Stress - genetics

Virulence Factors - metabolism

Mutagenesis - physiology

Ascomycota - metabolism

Superoxide Dismutase - metabolism

Agrobacterium-mediated transformation (AMT) was used to identify potential virulence factors in Sclerotinia sclerotiorum. Screening AMT transformants identified two mutants showing significantly reduced virulence. The mutants showed growth rate, sclerotial formation, and oxalate production similar to that of the wild type. The mutation was due to a single T-DNA insertion at 212 bp downstream of the Cu/Zn superoxide dismutase (SOD) gene (SsSOD1, SS1G_00699). Expression levels of SsSOD1 were significantly increased under oxidative stresses or during plant infection in the wild-type strain but could not be detected in the mutant. SsSOD1 functionally complemented the Cu/Zn SOD gene in a Δsod1 Saccharomyces cerevisiae mutant. The SOD mutant had increased sensitivity to heavy metal toxicity and oxidative stress in culture and reduced ability to detoxify superoxide in infected leaves. The mutant also had reduced expression levels of other known pathogenicity genes such as endo-polygalacturanases sspg1 and sspg3. The functions of SsSOD1 were further confirmed by SsSOD1-deletion mutation. Like the AMT insertion mutant, the SsSOD1-deletion mutant exhibited normal growth rate, sclerotial formation, oxalate production, increased sensitivity to metal and oxidative stress, and reduced virulence. These results suggest that SsSOD1, while not being required for saprophytic growth and completion of the life cycle, plays critical roles in detoxification of reactive oxygen species during host-pathogen interactions and is an important virulence factor of Sclerotinia sclerotiorum.

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Title: Random T-DNA mutagenesis identifies a Cu/Zn superoxide dismutase gene as a virulence factor of Sclerotinia sclerotiorum
Creators: Liangsheng Xu - Department of Plant Pathology, Washington State University, Pullman, WA, USA
Weidong Chen
Publication Details: Molecular plant-microbe interactions, Vol.26(4), pp.431-441
Academic Unit: Plant Pathology, Department of
Publisher: United States
Identifiers: 99900547698901842
Language: English
Resource Type: Journal article