Superoxide (O2.-) accumulation contributes to symptomless (type I) nonhost resistance of plants to biotrophic pathogens.
Plant Physiol Biochem
; 128: 115-125, 2018 Jul.
Article
em En
| MEDLINE
| ID: mdl-29775863
ABSTRACT
Nonhost resistance is the most common form of disease resistance exhibited by plants against most pathogenic microorganisms. Type I nonhost resistance is symptomless (i.e. no macroscopically visible cell/tissue death), implying an early halt of pathogen growth. The timing/speed of defences is much more rapid during type I nonhost resistance than during type II nonhost and host ("gene-for-gene") resistance associated with a hypersensitive response (localized necrosis, HR). However, the mechanism(s) underlying symptomless (type I) nonhost resistance is not entirely understood. Here we assessed accumulation dynamics of the reactive oxygen species superoxide (O2.-) during interactions of plants with a range of biotrophic and hemibiotrophic pathogens resulting in susceptibility, symptomless nonhost resistance or host resistance with HR. Our results show that the timing of macroscopically detectable superoxide accumulation (1-4 days after inoculation, DAI) is always associated with the speed of the defense response (symptomless nonhost resistance vs. host resistance with HR) in inoculated leaves. The relatively early (1 DAI) superoxide accumulation during symptomless nonhost resistance of barley to wheat powdery mildew (Blumeria graminis f. sp. tritici) is localized to mesophyll chloroplasts of inoculated leaves and coupled to enhanced NADPH oxidase (EC 1.6.3.1) activity and transient increases in expression of genes regulating superoxide levels and cell death (superoxide dismutase, HvSOD1 and BAX inhibitor-1, HvBI-1). Importantly, the partial suppression of symptomless nonhost resistance of barley to wheat powdery mildew by heat shock (49⯰C, 45â¯s) and antioxidant (SOD and catalase) treatments points to a functional role of superoxide in symptomless (type I) nonhost resistance.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Doenças das Plantas
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Plantas
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Ascomicetos
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Superóxidos
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Resistência à Doença
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Plant Physiol Biochem
Assunto da revista:
BIOQUIMICA
/
BOTANICA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Hungria