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A differentially regulated AP 2/ ERF transcription factor gene cluster acts downstream of a MAP kinase cascade to modulate terpenoid indole alkaloid biosynthesis in Catharanthus roseus
Author(s) -
Paul Priyanka,
Singh Sanjay K.,
Patra Barunava,
Sui Xueyi,
Pattanaik Sitakanta,
Yuan Ling
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.14252
Subject(s) - catharanthus roseus , gene cluster , biology , jasmonic acid , gene , biochemistry , transcription factor , biosynthesis , myb , kinase , microbiology and biotechnology
SummaryCatharanthus roseus produces bioactive terpenoid indole alkaloids ( TIA s), including the chemotherapeutics, vincristine and vinblastine. Transcriptional regulation of TIA biosynthesis is not fully understood. The jasmonic acid ( JA )‐responsive AP 2/ ERF transcription factor ( TF ), ORCA 3, and its regulator, Cr MYC 2, play key roles in TIA biosynthesis. ORCA 3 forms a physical cluster with two uncharacterized AP 2/ ERF s, ORCA 4 and 5. Here, we report that (1) the ORCA gene cluster is differentially regulated; (2) ORCA 4, while overlapping functionally with ORCA 3, modulates an additional set of TIA genes. Unlike ORCA 3, ORCA 4 overexpression resulted in dramatic increase of TIA accumulation in C. roseus hairy roots. In addition, Cr MYC 2 is capable of activating ORCA 3 and co‐regulating TIA pathway genes concomitantly with ORCA 3. The ORCA gene cluster and Cr MYC 2 act downstream of a MAP kinase cascade that includes a previously uncharacterized MAP kinase kinase, Cr MAPKK 1. Overexpression of Cr MAPKK 1 in C. roseus hairy roots upregulated TIA pathways genes and increased TIA accumulation. This work provides detailed characterization of a TF gene cluster and advances our understanding of the transcriptional and post‐translational regulatory mechanisms that govern TIA biosynthesis in C. roseus .