RRC ID 65585
Author Akiyama R, Nakayasu M, Umemoto N, Kato J, Kobayashi M, Lee HJ, Sugimoto Y, Iijima Y, Saito K, Muranaka T, Mizutani M.
Title Tomato E8 Encodes a C-27 Hydroxylase in Metabolic Detoxification of α-Tomatine during Fruit Ripening.
Journal Plant Cell Physiol
Abstract Tomato (Solanum lycopersicum) contains α-tomatine, a steroidal glycoalkaloid (SGA) that contributes to its defense against pathogens and herbivores through its bitter taste and toxicity. It accumulates at high levels in all the plant tissues, especially in leaves and immature green fruits, whereas it decreases during fruit ripening through metabolic conversion to the nontoxic esculeoside A, which accumulates in the mature red fruit. This study aimed to identify the gene encoding a C-27 hydroxylase that is a key enzyme in the metabolic conversion of α-tomatine to esculeoside A. The E8 gene, encoding a 2-oxoglutalate-dependent dioxygenase, is well-known as an inducible gene in response to ethylene during fruit ripening. The recombinant E8 was found to catalyze the C-27 hydroxylation of lycoperoside C to produce prosapogenin A and is designated as Sl27DOX. The ripe fruit of E8/Sl27DOX-silenced transgenic tomato plants accumulated lycoperoside C and exhibited decreased esculeoside A levels compared with the wild-type plants. Furthermore, E8/Sl27DOX-deletion in tomato accessions resulted in higher lycoperoside C levels in ripe fruit than in wild-type plants. Thus, E8/Sl27DOX functions as a C-27 hydroxylase of lycoperoside C in the metabolic detoxification of α-tomatine during tomato fruit ripening, and the efficient detoxification by E8/27DOX may provide an advantage in the domestication of cultivated tomatoes.
Published 2021-6-8
DOI 10.1093/pcp/pcab080
PII 6294823
PMID 34100555
IF 3.929
Resource
Tomato TOMJPF00001 (Micro-Tom)