Ethylene-dependent salicylic acid regulates an expanded cell death response to a plant pathogen.
The molecular events associated with susceptible plant responses to disease-causing organisms are not well understood. We have previously shown that ethylene-insensitive tomato plants infected with Xanthomonas campestris pv. vesicatoria have greatly reduced disease symptoms relative to wild-type cultivars. Here we show that salicylic acid (SA) is also an important component of the susceptible disease response. SA accumulates in infected wild-type tissues and is correlated with necrosis but does not accumulate in ethylene-insensitive plants. Exogenous feeding of SA to ethylene-deficient plants restores necrosis, indicating that reduced disease symptoms are associated with failure to accumulate SA. These results indicate a mechanism for co-ordination of phytohormone signals that together constitute a susceptible response to pathogens.
O'Donnell
P J
PJ
Department of Horticultural Sciences, University of Florida, Gainesville, FL 32611, USA.
Jones
J B
JB
Antoine
F R
FR
Ciardi
J
J
Klee
H J
HJ
D016923:Cell Death; D005030:Ethylenes / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000166:cytology* / Q000382:microbiology; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction; D016959:Xanthomonas campestris / Q000502:physiology*
D005030:Ethylenes; C036216:ethylene; D020156:Salicylic Acid