BmG10H-1 transcript from B. monnieri was functionally active. BmG10H-1 promoter drives GUS activity in response to MeJA and wounding. BmMYB35 regulates BmG10H-1 transcript by binding to its promoter.
Geraniol 10-hydroxylase (G10H) is one of the important regulatory
cytochrome P450 monooxygenase, which is involved in the biosynthesis of
monoterpene alkaloids. However, G10H is not characterized at the enzymatic or at the regulatory aspect in B. monnieri. In the present study, we have identified two transcripts of BmG10H (BmG10H-1and BmG10H-2) and characterized the
methyl jasmonate (MeJA) and
wound responsive BmG10H-1 transcript from B. monnieri. BmG10H-1 showed induced expression after 3 h of MeJA and wounding treatment in the shoot. Yeast purified recombinant BmG10H-1
protein is enzymatically active, having Vmax of 0.16 µMsec-1 μg-1
protein and catalyzes the hydroxylation of
geraniol to 10-hydroxy
geraniol. The BmG10H-1 promoter was isolated by using the genome walking method. BmG10H-1 promoter can drive GUS expression in transgenic Arabidopsis thaliana. GUS activity of MeJA and
wound-treated Arabidopsis seedlings were found to be increased as compared to the control untreated seedlings, whereas no GUS activity was found in deleted MeJA responsive and W-box cis-elements. This shows that the BmG10H-1 promoter contains functional MeJA (TGACG) and
wound responsive (TGACCT) cis-elements. Further, shoot specific and MeJA responsive recombinant BmMYB35
protein was purified, which binds with the MYB recognition cis-
element (TGGTTA) present in the BmG10H-1 promoter and transcriptionally activates the reporter gene in yeast. In conclusion, the characterization of MeJA and
wound responsive BmG10H-1 provides novel information about its transcriptional regulation by binding with MYB
transcription factor in B. monnieri.