Characterization of gossypol biosynthetic pathway.
Proc Natl Acad Sci U S A
; 115(23): E5410-E5418, 2018 06 05.
Article
em En
| MEDLINE
| ID: mdl-29784821
ABSTRACT
Gossypol and related sesquiterpene aldehydes in cotton function as defense compounds but are antinutritional in cottonseed products. By transcriptome comparison and coexpression analyses, we identified 146 candidates linked to gossypol biosynthesis. Analysis of metabolites accumulated in plants subjected to virus-induced gene silencing (VIGS) led to the identification of four enzymes and their supposed substrates. In vitro enzymatic assay and reconstitution in tobacco leaves elucidated a series of oxidative reactions of the gossypol biosynthesis pathway. The four functionally characterized enzymes, together with (+)-δ-cadinene synthase and the P450 involved in 7-hydroxy-(+)-δ-cadinene formation, convert farnesyl diphosphate (FPP) to hemigossypol, with two gaps left that each involves aromatization. Of six intermediates identified from the VIGS-treated leaves, 8-hydroxy-7-keto-δ-cadinene exerted a deleterious effect in dampening plant disease resistance if accumulated. Notably, CYP71BE79, the enzyme responsible for converting this phytotoxic intermediate, exhibited the highest catalytic activity among the five enzymes of the pathway assayed. In addition, despite their dispersed distribution in the cotton genome, all of the enzyme genes identified show a tight correlation of expression. Our data suggest that the enzymatic steps in the gossypol pathway are highly coordinated to ensure efficient substrate conversion.
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Bases de dados:
MEDLINE
Assunto principal:
Gossipol
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
China