AUTHOR=Li Jia , Li Changfu , Gou Junbo , Zhang Yansheng 

TITLE=Molecular Cloning and Functional Characterization of a Novel Isoflavone 3′-O-methyltransferase from Pueraria lobata

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.00793

DOI=10.3389/fpls.2016.00793

ISSN=1664-462X

ABSTRACT=<p><italic>Pueraria lobata</italic> roots accumulate 3′-, 4′- and 7-<italic>O</italic>-methylated isoflavones and many of these methylated compounds exhibit various pharmacological activities. Either the 4′- or 7-<italic>O</italic>-methylation activity has been investigated at molecular levels in several legume species. However, the gene encoding the isoflavone 3′-<italic>O-</italic>methyltransferase (OMT) has not yet been isolated from any plant species. In this study, we reported the first cDNA encoding the isoflavone 3′-OMT from <italic>P. lobata</italic> (designated PlOMT4). Heterologous expressions in yeast and <italic>Escherichia coli</italic> cells showed that the gene product exhibits an enzyme activity to methylate the 3′-hydroxy group of the isoflavone substrate. The transcript abundance of <italic>PlOMT4</italic> matches well with its enzymatic product in different organs of <italic>P. lobata</italic> and in the plant roots in response to methyl jasmonate elicitation. Integration of the biochemical with metabolic and transcript data supported the proposed function of PlOMT4. The identification of <italic>PlOMT4</italic> would not only help to understand the isoflavonoid metabolism in <italic>P. lobata</italic> but also potentially provide an enzyme catalyst for methylating existing drug candidates to improve their hydrophobicity.</p>