Activities of lipoxygenase and phenylalanine ammonia lyase in poplar leaves induced by insect herbivory and volatiles

• DOI: 10.1007/s11676-009-0063-6
• Publication Date: 2009-11-09T06:45:04Z
• Authors: Zeng-hui Hu; Wen Zhang; Ying-bai Shen; Huai-jun Fu; Xiao-hua Su; Zhi-yi Zhang
• Keywords: Methyl jasmonate; Phenylalanine ammonia-lyase; Phenylpropanoid; Green leaf volatiles; Methyl salicylate

A study was conducted to explore the defense response in woody plants after insect herbivory. The activities of two enzymes, lipoxygenase (LOX), a key enzyme of jasmonate (JA) pathway, and phenylalanine ammonia lyase (PAL), a rate-limiting enzyme of phenylpropanoid pathway, were measured in the leaves of one-year-old poplar (Populus simonii × P. pyramidalis ‘Opera 8277’) cuttings after Clostera anachoreta larvae attack. The results show that the increased activities of LOX and PAL were found not only in the leaves wounded by C. anachoreta larvae but also in their upper systemic leaves, indicating that JA and phenylpropanoid pathways were activated, and the defense response was stimulated systemically. The increase in LOX and PAL activities in neighboring intact poplar cuttings suggested that there exists the interplant communication between poplar plants mediated by the herbivore-induced volatiles. Methyl jasmonate (MeJA) was also proved to be an airborne signal to induce defense response in P. simonii × P. pyramidalis ‘Opera 8277’ cuttings.