Resistance to Botrytis cinerea in sitiens, an abscisic acid-deficient tomato mutant, involves timely production of hydrogen peroxide and cell wall modifications in the epidermis.
Plant defense mechanisms against necrotrophic pathogens, such as Botrytis cinerea, are considered to be complex and to differ from those that are effective against biotrophs. In the abscisic acid-deficient sitiens tomato (Solanum lycopersicum) mutant, which is highly resistant to B. cinerea, accumulation of hydrogen peroxide (H(2)O(2)) was earlier and stronger than in the susceptible wild type at the site of infection. In sitiens, H(2)O(2) accumulation was observed from 4 h postinoculation (hpi), specifically in the leaf epidermal cell walls, where it caused modification by protein cross-linking and incorporation of phenolic compounds. In wild-type tomato plants, H(2)O(2) started to accumulate 24 hpi in the mesophyll layer and was associated with spreading cell death. Transcript-profiling analysis using TOM1 microarrays revealed that defense-related transcript accumulation prior to infection was higher in sitiens than in wild type. Moreover, further elevation of sitiens defense gene expression was stronger than in wild type 8 hpi both in number of genes and in their expression levels and confirmed a role for cell wall modification in the resistant reaction. Although, in general, plant defense-related reactive oxygen species formation facilitates necrotrophic colonization, these data indicate that timely hyperinduction of H(2)O(2)-dependent defenses in the epidermal cell wall can effectively block early development of B. cinerea.
Asselbergh
Bob
B
Laboratory of Phytopathology , Ghent University, B-9000 Ghent, Belgium.
Curvers
Katrien
K
Franca
Soraya C
SC
Audenaert
Kris
K
Vuylsteke
Marnik
M
Van Breusegem
Frank
F
Höfte
Monica
M
D000040:Abscisic Acid / Q000378:metabolism; D020171:Botrytis / Q000502:physiology*; D002473:Cell Wall / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D020869:Gene Expression Profiling; D017343:Genes, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D009154:Mutation; D009195:Peroxidase / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D010935:Plant Diseases; D019441:Plant Epidermis / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism
D010636:Phenols; D010940:Plant Proteins; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D009195:Peroxidase