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Two CYP716A subfamily cytochrome P450 monooxygenases of sweet basil play similar but nonredundant roles in ursane‐ and oleanane‐type pentacyclic triterpene biosynthesis
Author(s) -
Misra Rajesh Chandra,
Sharma Shubha,
Garg Anchal,
Chanotiya Chandan Singh,
Ghosh Sumit
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14412
Subject(s) - oleanolic acid , oleanane , ursolic acid , monooxygenase , biochemistry , biosynthesis , ocimum , methyl jasmonate , triterpene , biology , sweet basil , cytochrome p450 , botany , enzyme , gene , basilicum , medicine , alternative medicine , pathology
Summary The medicinal plant sweet basil ( Ocimum basilicum ) accumulates bioactive ursane‐ and oleanane‐type pentacyclic triterpenes ( PCT s), ursolic acid and oleanolic acid, respectively, in a spatio‐temporal manner; however, the biosynthetic enzymes and their contributions towards PCT biosynthesis remain to be elucidated. Two CYP 716A subfamily cytochrome P450 monooxygenases ( CYP 716A252 and CYP 716A253) are identified from a methyl jasmonate‐responsive expression sequence tag collection and functionally characterized, employing yeast ( Saccharomyces cerevisiae ) expression platform and adapting virus‐induced gene silencing ( VIGS ) in sweet basil. CYP 716A252 and CYP 716A253 catalyzed sequential three‐step oxidation at the C‐28 position of α‐amyrin and β‐amyrin to produce ursolic acid and oleanolic acid, respectively. Although CYP 716A253 was more efficient than CYP 716A252 for amyrin C‐28 oxidation in yeast, VIGS revealed essential roles for both of these CYP 716As in constitutive biosynthesis of ursolic acid and oleanolic acid in sweet basil leaves. However, CYP 716A253 played a major role in elicitor‐induced biosynthesis of ursolic acid and oleanolic acid. Overall, the results suggest similar as well as distinct roles of CYP 716A252 and CYP 716A253 for the spatio‐temporal biosynthesis of PCT s. CYP 716A252 and CYP 716A253 might be useful for the alternative and sustainable production of PCT s in microbial host, besides increasing plant metabolite content through genetic modification.