An herbivore elicitor activates the gene for indole emission in maize.
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.
Frey
M
M
Lehrstuhl für Genetik, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany. Monika.Frey@bio.tum.de
Stettner
C
C
Pare
P W
PW
Schmelz
E A
EA
Tumlinson
J H
JH
Gierl
A
A
D000818:Animals; D001483:Base Sequence; D018744:DNA, Plant; D005227:Fatty Acids / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005973:Glutamine / Q000031:analogs & derivatives / Q000378:metabolism*; D005994:Glycerophosphates / Q000096:biosynthesis; D007209:Indole-3-Glycerol-Phosphate Synthase / Q000235:genetics* / Q000378:metabolism; D007211:Indoles / Q000378:metabolism*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018411:Spodoptera / Q000378:metabolism; D015533:Transcriptional Activation; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics; D017962:alpha-Linolenic Acid / Q000031:analogs & derivatives / Q000378:metabolism*
D018744:DNA, Plant; D005227:Fatty Acids; D005994:Glycerophosphates; D007211:Indoles; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C419781:volicitin; D017962:alpha-Linolenic Acid; D005973:Glutamine; C008117:indoleglycerol phosphate; C030374:indole; D007209:Indole-3-Glycerol-Phosphate Synthase