PubAg

Main content area

An herbivore elicitor activates the gene for indole emission in maize

Author:
Frey, M., Stettner, C., Pare, P.W., Schmelz, E.A., Tumlinson, J.H., Gierl, A.
Source:
Proceedings of the National Academy of Sciences of the United States of America 2000 v.97 no.26 pp. 14801
ISSN:
0027-8424
Subject:
Zea mays, lyases, genes, complementary DNA, nucleotide sequences, enzyme activity, gene expression, messenger RNA, Spodoptera exigua, linolenic acid, glutamine, defense mechanisms, indoles, introns, exons, emissions, species differences
Abstract:
Maize and a variety of other plant species release volatile compounds in response to herbivore attack that serve as chemical cues to signal natural enemies of the feeding herbivore. N-(17-hydroxylinolenoyl)-L-glutamine is an elicitor component that has been isolated and chemically characterized from the regurgitant of the herbivore-pest beet armyworm. This fatty acid derivative, referred to as volicitin, triggers the synthesis and release of volatile components, including terpenoids and indole in maize. Here we report on a previously unidentified enzyme, indole-3-glycerol phosphate lyase (IGL), that catalyzes the formation of free indole and is selectively activated by volicitin. IGL's enzymatic properties are similar to BX1, a maize enzyme that serves as the entry point to the secondary defense metabolites DIBOA and DIMBOA. Gene-sequence analysis indicates that Igl and Bx1 are evolutionarily related to the tryptophan synthase alpha subunit.
Agid:
34386
Handle:
10113/34386