Articles
SALICYLIC ACID AND CHITINASE IN INFECTED CUCUMBER PLANTS
Article number
381_46
Pages
371 – 374
Language
Abstract
Attacks of plants by necrotizing pathogens leads to local defense reactions and may induce subsequent long-lasting resistance, defined as systemic acquired resistance (SAR) in tissues remotely located from the site of the initial infection.
Salicylic acid (SA) was proposed as a putative signalling molecule for the induction of SAR. Pathogenesis-Related (PR) proteins including chitinase are generally thought to play a crucial role in the mechanisms of disease resistance both locally and systemically.
Cucumber plants were inoculated with Pseudomonas lachrymans on leaf 1. PR proteins, chitinase and endogenous levels of SA were monitored in the inoculated leaf 1, in leaf 2 and in roots.
The earliest significative increase in SA occured 9h and 12h post-inoculation in leaf 1 (up to 4.5-fold higher than controls) and in leaf 2 (up to 2.4-fold higher than controls) respectively, whereas no free SA were detected in roots from control and infected plants 5 d post-inoculation.
Chitinase was first detected after 12h and 18h in leaves 1 and 2 respectively.
Therefore, both local and systemic increase in endogenous SA are consistent with a possible role of SA in the induction of chitinase in leaves of cucumber plants infected with Pseudomonas lachrymans.
Salicylic acid (SA) was proposed as a putative signalling molecule for the induction of SAR. Pathogenesis-Related (PR) proteins including chitinase are generally thought to play a crucial role in the mechanisms of disease resistance both locally and systemically.
Cucumber plants were inoculated with Pseudomonas lachrymans on leaf 1. PR proteins, chitinase and endogenous levels of SA were monitored in the inoculated leaf 1, in leaf 2 and in roots.
The earliest significative increase in SA occured 9h and 12h post-inoculation in leaf 1 (up to 4.5-fold higher than controls) and in leaf 2 (up to 2.4-fold higher than controls) respectively, whereas no free SA were detected in roots from control and infected plants 5 d post-inoculation.
Chitinase was first detected after 12h and 18h in leaves 1 and 2 respectively.
Therefore, both local and systemic increase in endogenous SA are consistent with a possible role of SA in the induction of chitinase in leaves of cucumber plants infected with Pseudomonas lachrymans.
Authors
P. Meuwly, W. Mölders, K. Summermatter, L. Sticher, J.-P. Métraux
Keywords
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