RRC ID 58209
著者 Nakayasu M, Akiyama R, Kobayashi M, Lee HJ, Kawasaki T, Watanabe B, Urakawa S, Kato J, Sugimoto Y, Iijima Y, Saito K, Muranaka T, Umemoto N, Mizutani M.
タイトル Identification of α-Tomatine 23-Hydroxylase Involved in the Detoxification of a Bitter Glycoalkaloid.
ジャーナル Plant Cell Physiol
Abstract Tomato plants (Solanum lycopersicum) contain steroidal glycoalkaloid α-tomatine, which functions as a chemical barrier to pathogens and predators. α-Tomatine accumulates in all tissues and at particularly high levels in leaves and immature green fruits. The compound is toxic and causes a bitter taste, but its presence decreases through metabolic conversion to nontoxic esculeoside A during fruit ripening. This study identifies the gene encoding a 23-hydroxylase of α-tomatine, which is a key to this process. Some 2-oxoglutarate-dependent dioxygenases were selected as candidates for the metabolic enzyme, and Solyc02g062460, designated Sl23DOX, was found to encode α-tomatine 23-hydroxylase. Biochemical analysis of the recombinant Sl23DOX protein demonstrated that it catalyzes the 23-hydroxylation of α-tomatine and the product spontaneously isomerizes to neorickiioside B, which is an intermediate in α-tomatine metabolism that appears during ripening. Leaves of transgenic tomato plants overexpressing Sl23DOX accumulated not only neorickiioside B but also another intermediate, lycoperoside C (23-O-acetylated neorickiioside B). Furthermore, the ripe fruits of Sl23DOX-silenced transgenic tomato plants contained lower levels of esculeoside A but substantially accumulated α-tomatine. Thus, Sl23DOX functions as α-tomatine 23-hydroxylase during the metabolic processing of toxic α-tomatine in tomato fruit ripening and is a key enzyme in the domestication of cultivated tomatoes.
巻・号 61(1)
ページ 21-28
公開日 2020-1-1
DOI 10.1093/pcp/pcz224
PII 5670534
PMID 31816045
MeSH Fruit / metabolism Gene Expression Regulation, Plant Inactivation, Metabolic Mixed Function Oxygenases / genetics Mixed Function Oxygenases / metabolism* Plant Leaves / metabolism Plants, Genetically Modified / metabolism Recombinant Proteins Solanum lycopersicum / enzymology* Solanum lycopersicum / genetics Solanum lycopersicum / metabolism* Taste* Tomatine / analogs & derivatives* Tomatine / metabolism*
IF 4.062
引用数 0
リソース情報
トマト TOMJPF00001(Micro-Tom) LEFL2019P01 LEFL2027P04 LEFL2046F14