Cloning of the key genes in maize oxylipins pathways and their roles in herbivore induced defense
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To gain an understanding of the molecular basis of signaling pathways in herbivore-induced maize plant defense, three key genes,ZmAOS, ZmAOC andZmHPL, which are involved in the biosynthesis of oxylipin signals, have been cloned using RT-PCR in this study. Beet armyworm (BAW) infestation induced the systemic expression of the key genes involved in the biosynthesis of oxylipin signals similar to exogenous methyl jasmonate (MeJA). Moreover, the systemic expression patterns of maize defense-related genes were similar between maize leaves induced by jasmonic acid (JA) and damaged by BAW. Previous treatment with salicyhydroxamic acid (SHAM), an inhibitor of jasmonates (JAs) signal pathway followed by BAW infestation did not induce the systemic expression of the defense-related genes. Exposure to the vapors of green leafy volatiles (GLVs, (Z)-3-hexen-1-ol, (E)-2-hexenal, (E)-3-hexenal) and β-ocimene induced the expression of the defense-related genes, as well as the key genes involved in biosynthesis of JAs. However, previous treatment with SHAM clearly decreased the transcript levels of the defense genes induced by (Z)-3-hexen-1-ol, (E)-2-hexenal and (E)-3-hexenal. These results demonstrate the major role of oxylipin signal pathway in herbivore-induced maize chemical defense. JA was the endogenous signal in the process of herbivore-induced maize systemic defense. GLVs, another group of oxylipin, played an important role in the process of herbivore-induced systemic defense outside the plant. Furthermore, the expression of defense-related genes induced by GLVs was partially dependent on JAs signal pathway, while β-ocimene induction was independent of JAs signal pathway.
Keywordsmaize beet armyworm (BAW) herbivore-induced defense oxylipin signaling pathways jasmonates (JAs) green leafy volatiles (GLVs)
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- 1.Karban, R., Baldwin, I. T., Induced Response to Herbivory, Chicago: The University of Chicago Press, 1997.Google Scholar
- 4.Ryan, C. A., The systemin signaling pathway: Differential activation of plant defensive genes, Biochem. Biophy. Acta, 2000, 1477: 112–121.Google Scholar
- 6.Lou, Y. G., Cheng, J. A., Herbivore-induced plant volatiles: Primary characteristics, ecological functions and its release mechanism, Acta Ecol. Sin. (in Chinese), 2000, 20: 1097–1106.Google Scholar
- 16.Thaler, J. S., Fidantsef, A. L., Bostock, R. M., Antagonism between jasmonate- and salicylate-mediated induced plant resistance: Effects of concentration and timing of elicitation on defense-related proteins, herbivores, and pathogen performace in tomato, J. Chem. Ecol., 2002, 28: 1131–1159.CrossRefGoogle Scholar
- 17.Gui, L. Y., Liu, S. S., Chen, Z. M., Plant resistance to insects induced by application of exogenous jasmonic acid and methyl jasmonate, Acta Entomol. Sin. (in Chinese), 2004, 47: 507–514.Google Scholar
- 18.Lu, Y. B., Liu, S. S., Effects of plant responses induced by exogenous jasmonic acid on host-selection behavior ofCotesia plutellae (Hymenoptera: Braconidae), Acta Entomol. Sin. (in Chinese), 2004, 47: 206–212.Google Scholar
- 42.Kan, W., Zhang, F., Zhang, Z. N., Behavior-modulating plant volatile chemical for aphids, Chin. Sci. Bull., 2002, 47: 115–117.Google Scholar
- 49.Schmelz, E. A., Alborn, H. T., Banchio, E. et al., Quantitative relationships between induced jasmonic acid levels and volatile emission inZea mays duringSpodopterea exigua herbivory, Planta, 2003, 216: 665–673.Google Scholar
- 51.Li, G. H., Chen, Q. J., Pang, Y., Studies of artificial diets for the beet armyworm,Spodoptera exigue, Acta Sci. Nat. Univ. Sun Yat-set. (in Chinese), 1998, 37: 1–5.Google Scholar