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Only an early nitric oxide burst and the following wave of secondary nitric oxide generation enhanced effective defence responses of pelargonium to a necrotrophic pathogen
Author(s) -
FloryszakWieczorek Jolanta,
Arasimowicz Magdalena,
Milczarek Grzegorz,
Jelen Henryk,
Jackowiak Hanna
Publication year - 2007
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2007.02142.x
Subject(s) - pelargonium , nitric oxide , catalase , pathogen , hydrogen peroxide , apx , peroxidase , chemistry , botrytis cinerea , respiratory burst , microbiology and biotechnology , biology , oxidative stress , botany , biochemistry , enzyme , organic chemistry
Summary• Participation of nitric oxide (NO) in cross‐talk between ivy pelargonium ( Pelargonium peltatum ) leaves and Botrytis cinerea was investigated using electrochemical and biochemical approaches. • In response to the necrotroph, leaves initiated a near‐immediate NO burst, but the specificity of its generation was dependent on the genetic makeup of the host plant. • In the resistant cultivar, a strong NO burst was followed by a wave of secondary NO generation, shown by bio‐imaging with DAF‐2DA. The epicentre of NO synthesis was located in targeted cells, which exhibited a TUNEL‐positive reaction. Soon after the challenge, an elevated concentration of hydrogen peroxide (H 2 O 2 ) was correlated with a reversible inhibition of catalase (CAT), ascorbate peroxidase (APX), and suppression of ethylene synthesis. The induced NO generation initially expanded and then gradually disappeared on successive days, provoking noncell‐death‐associated resistance with an enhanced pool of antioxidants, which finally favoured the maintenance of homeostasis of surrounding cells. • By contrast, in the susceptible pelargonium, a weak NO burst was recorded and further NO generation increased only as the disease progressed, which was accompanied by very intensive H 2 O 2 and ethylene synthesis. The pathogen colonizing susceptible cells also acquired the ability to produce considerable amounts of NO and enhanced nitrosative and oxidative stress in host tissues.