The Expression of Systemic Acquired Resistance (SAR) Related Genes are Induced by Heat Stress in Cucumber plant.

Abstract

SAR is induced for example, after pathogen infection or by salicylic acid (SA). The pathogenesis-related (PR) proteins and phenylaranin ammonialyase (PAL) are known to be accumulated rapidly in SAR-induced plants. We examined the expression level of PR 8 and 9 from cucumber leaves after soaking into 45°C water in two minutes by real-time RT-PCR. The results indicated that the response to heat stress was as rapid as that to the SA treatment. This treatment also induced the expression of PAL, indicating that heat stress activate SAR via phenylpropanoid pathway like pathogen infection. However, they were not expressed by 35°Cand 40°C. We also found that pathogen infection was suppressed by heat stress treatment in cucumber.