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ARS Home » Research » Publications at this Location » Publication #110707
Title: INDIRECT PLANT DEFENSES ARE INDUCED BY METHYL JASMONATE IN TWO COTTON VARIETIES

Author
item Rodriguez Saona, Cesar
item Crafts-Brandner, Steven

Submitted to: National Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Jasmonic acid and methyl jasmonate (MeJA) are phytohormones involved in the induction of direct (secondary metabolites) and indirect (volatiles that attract natural enemies) plant defenses in response to herbivore damage. Plants treated with these jasmonates might attract more natural enemies if the volatile blend emitted by the treated plants is similar to that of plants damaged by herbivores. We investigated the effect of exogenous MeJ on the emission of herbivore-induced volatiles in two cotton varieties: a glanded cv. Deltapine 5415 and a glandless cv. Coker 100A. At 18 micromoles of MeJA per plant, MeJA induced a volatile blend that was qualitatively similar to glandless cotton damaged by the beet armyworm, Spodoptera exigua. Treatment of glanded cotton with MeJA did not induce the release of any of the terpenes that are stored in the leaf glands i.e., alpha-pinene, beta-pinene, alpha-humulene, and beta-caryophellene. In contrast, these compounds are emitted in relatively large amounts from glanded cotton after herbivore damage. We are currently investigating the timing of volatile emission from cotton plants treated with MeJA. In addition, we will determine if MeJA induces a systemic response in untreated cotton leaves. Our results indicate that jasmonates play an important role in the induction of plant volatiles that attract natural enemies.