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 |