First published online October 13, 2009; 10.1105/tpc.108.063677
The Plant Cell 21:3315-3325 (2009)
© 2009 American Society of Plant Biologists
OPEN ACCESS ARTICLE
CYP76M7 Is an ent-Cassadiene C11 -Hydroxylase Defining a Second Multifunctional Diterpenoid Biosynthetic Gene Cluster in Rice[W],[OA]
Sivakumar Swaminathan1,
Dana Morrone1,
Qiang Wang1,
D. Bruce Fulton and
Reuben J. Peters2
Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011
2 Address correspondence to rjpeters{at}iastate.edu.
Biosynthetic gene clusters are common in microbial organisms, but rare in plants, raising questions regarding the evolutionary forces that drive their assembly in multicellular eukaryotes. Here, we characterize the biochemical function of a rice (Oryza sativa) cytochrome P450 monooxygenase, CYP76M7, which seems to act in the production of antifungal phytocassanes and defines a second diterpenoid biosynthetic gene cluster in rice. This cluster is uniquely multifunctional, containing enzymatic genes involved in the production of two distinct sets of phytoalexins, the antifungal phytocassanes and antibacterial oryzalides/oryzadiones, with the corresponding genes being subject to distinct transcriptional regulation. The lack of uniform coregulation of the genes within this multifunctional cluster suggests that this was not a primary driving force in its assembly. However, the cluster is dedicated to specialized metabolism, as all genes in the cluster are involved in phytoalexin metabolism. We hypothesize that this dedication to specialized metabolism led to the assembly of the corresponding biosynthetic gene cluster. Consistent with this hypothesis, molecular phylogenetic comparison demonstrates that the two rice diterpenoid biosynthetic gene clusters have undergone independent elaboration to their present-day forms, indicating continued evolutionary pressure for coclustering of enzymatic genes encoding components of related biosynthetic pathways.
This article has been cited by other articles:

|
 |

|
 |
 
E. Wegel, R. Koumproglou, P. Shaw, and A. Osbourn
Cell Type-Specific Chromatin Decondensation of a Metabolic Gene Cluster in Oats
PLANT CELL,
December 1, 2009;
21(12):
3926 - 3936.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|
|