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A peroxisomal thioesterase plays auxiliary roles in plant β‐oxidative benzoic acid metabolism
Author(s) -
Adebesin Funmilayo,
Widhalm Joshua R.,
Lynch Joseph H.,
McCoy Rachel M.,
Dudareva Natalia
Publication year - 2018
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13818
Subject(s) - peroxisome , phenylpropanoid , biochemistry , biology , thioesterase , coenzyme a , metabolic pathway , oxidative phosphorylation , metabolism , beta oxidation , biosynthesis , enzyme , gene , reductase
Summary Peroxisomal β‐oxidative degradation of compounds is a common metabolic process in eukaryotes. Reported benzoyl‐coenzyme A ( BA ‐CoA) thioesterase activity in peroxisomes from petunia flowers suggests that, like mammals and fungi, plants contain auxiliary enzymes mediating β‐oxidation. Here we report the identification of Petunia hybrida thioesterase 1 (Ph TE 1), which catalyzes the hydrolysis of aromatic acyl‐CoAs to their corresponding acids in peroxisomes. Ph TE 1 expression is spatially, developmentally and temporally regulated and exhibits a similar pattern to known benzenoid metabolic genes. Ph TE 1 activity is inhibited by free coenzyme A (CoA), indicating that Ph TE 1 is regulated by the peroxisomal CoA pool. Ph TE 1 downregulation in petunia flowers led to accumulation of BA ‐CoA with increased production of benzylbenzoate and phenylethylbenzoate, two compounds which rely on the presence of BA ‐CoA precursor in the cytoplasm, suggesting that acyl‐CoAs can be exported from peroxisomes. Furthermore, Ph TE 1 downregulation resulted in increased pools of cytoplasmic phenylpropanoid pathway intermediates, volatile phenylpropenes, lignin and anthocyanins. These results indicate that Ph TE 1 influences (i) intraperoxisomal acyl‐CoA/CoA levels needed to carry out β‐oxidation, (ii) efflux of β‐oxidative products, acyl‐CoAs and free acids, from peroxisomes, and (iii) flux distribution within the benzenoid/phenylpropanoid metabolic network. Thus, this demonstrates that plant thioesterases play multiple auxiliary roles in peroxisomal β‐oxidative metabolism.