Activities of lipoxygenase and phenylalanine ammonia lyase in poplar leaves induced by insect herbivory and volatiles
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.
KeywordsClostera anachoreta larvae lipoxygenase methyl jasmonate phenylalanine ammonia lyase Populus simonii × P. pyramidalis ‘Opera 8277’ cuttings
- Axelrod B, Cheesbrough TM, Leakso S. 1981. Lipoxygenase from soybeans. Methods in Enzymology, 7: 443–451.Google Scholar
- Constabel CP. 1999. A survey of herbivore-inducible defensive proteins and phytochemicals. In: Agrawal AA, Tuzun S, Bent E (eds), Inducible plant defenses against pathogens and herbivores: biochemistry, ecology, and agriculture. United States of America: American Phytopathological Society Press, pp. 137–166.Google Scholar
- Howe GA. 2004. Jasmonates as signals in the wound response. Journal of Plant Growth Regulation, 23: 223–237.Google Scholar
- Li L, Zhao Y, McCaig BC, Wingerd BA, Wang J, Whalon ME, Pichersky E, Howe GA. 2004. The tomato homolog of CORONATINE-INSENSITIVE1 is required for the maternal control of seed maturation, jasmonate-signaled defense responses and glandular trichome development. Plant Cell, 16: 126–143.CrossRefPubMedGoogle Scholar
- Wang L, Allmann S, Wu J, Baldwin IT. 2008. Comparisons of LIPOXYGENASE3- and JASMONATE-RESISTANT4/6-Silenced plants reveal that jasmonic acid and jasmonic acid-amino acid conjugates platy different roles in herbivore resistance of Nicotiana attenuata. Plant Physiology, 146: 904–915.CrossRefPubMedGoogle Scholar