European Journal of Plant Pathology

, Volume 129, Issue 2, pp 267–280

Influence of nitric oxide and reactive oxygen species on development of lettuce downy mildew in Lactuca spp.

  • Michaela Sedlářová
  • Marek Petřivalský
  • Jana Piterková
  • Lenka Luhová
  • Jindra Kočířová
  • Aleš Lebeda
Article

DOI: 10.1007/s10658-010-9626-9

Cite this article as:
Sedlářová, M., Petřivalský, M., Piterková, J. et al. Eur J Plant Pathol (2011) 129: 267. doi:10.1007/s10658-010-9626-9

Abstract

The role of nitric oxide and reactive oxygen species, molecules indispensable for plant-pathogen signalling, was studied in the Lactuca spp.-Bremia lactucae pathosystem. Using a leaf disc model the translaminar effect of various compounds affecting their metabolism was studied by light microscopy. Time course studies revealed a slowdown in the development of B. lactucae (race BL16) infection structures by rutin (scavenger of reactive nitrogen and oxygen species) and SNP (NO donor) within 48 h post inoculation, followed by a retardation of sporulation. Application of the specific NO scavenger, PTIO, accelerated penetration of B. lactucae but had no further effects on the plant-pathogen interaction. Inhibitors of NO synthase (L-NAME) and nitrate reductase (sodium tungstate) did not influence pathogen development. Our results suggest that drastic change in the NO: hydrogen peroxide ratio seems to determine the pathogen’s fate. NO synthase-like activity significantly increased early after B. lactucae challenge in resistant L. virosa. Confocal laser scanning microscopy revealed the accumulation of nitric oxide in the penetrated cells, pointing to a role in the initiation of the hypersensitive reaction. The tips of germ tubes and appressoria of B. lactucae also accumulated NO, suggesting an essential role for this molecule in penetration of the biotrophic pathogen. Additionally, temporal changes in endogenous levels of rutin and quercetin in extracts from Lactuca spp. leaves will be discussed in connection to their role as part of the antioxidative machinery that influences the plants’ susceptibility/resistance to lettuce downy mildew.

Keywords

Antioxidants Bremia lactucae Lactuca sativa Lactuca saligna Lactuca virosa Oomycete Oxidative stress Quercetin Rutin Sodium nitroprusside 

Abbreviations

DAF-FM DA

4-amino-5-(N-methylamino)-2′,7′-difluorofluorescein diacetate

hpi

hours post inoculation

HR

hypersensitive response

L-NAME

NG-nitro-L-arginine-methylester

NOS

nitric oxide synthase

NR

nitrate reductase

PTIO

2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide

PV

primary vesicle

ROS

reactive oxygen species

RNS

reactive nitrogen species

SNP

sodium nitroprusside

SD

standard deviation

SV

secondary vesicle

Copyright information

© KNPV 2010

Authors and Affiliations

  • Michaela Sedlářová
    • 1
  • Marek Petřivalský
    • 2
  • Jana Piterková
    • 2
  • Lenka Luhová
    • 2
  • Jindra Kočířová
    • 2
  • Aleš Lebeda
    • 1
  1. 1.Department of Botany, Faculty of SciencePalacký University in OlomoucOlomoucCzech Republic
  2. 2.Department of Biochemistry, Faculty of SciencePalacký University in OlomoucOlomoucCzech Republic

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