Reducing chilling injury and enhancing transcript levels of heat shock proteins, PR-proteins and alternative oxidase by methyl jasmonate and methyl salicylate in tomatoes and peppers.

摘要

Tomatoes (Lycopersicon esculentum) and sweet peppers (Capsicum annuum) treated with vapours of methyl jasmonate (MeJA) or methyl salicylate (MeSA) had markedly increased resistance to chilling injury and decreased incidence of decay during and after low temperature storage. Accumulation of classes I and II small heat shock protein (HSP) mRNAs was increased significantly by treatment of tomato fruits with MeJA and MeSA. Treated fruits also accumulated higher levels of transcripts from the HSP 70 family compared to untreated fruits. MeJA treatment also substantially enhanced mRNA levels of pathogenesis-related (PR)-2a, PR-2b and PR-3b. MeSA-treated fruits had significantly increased accumulation of PR-2b and PR-3a mRNAs compared to the control fruits. Two transcripts, 1.5 kb and 3.5 kb, of alternative oxidase (AOX) were detected by Northern blot analysis from sweet pepper fruits stored at 0 degrees C. Both transcripts reached maximum levels first in MeSA-treated fruits, second in MeJA-treated fruits and last in the control fruits. The results suggest that treatment of tomatoes and sweet peppers with MeJA or MeSA induces synthesis of some stress proteins, such as HSP, PR proteins and AOX, which leads to increased chilling tolerance and decay resistance..