| Title: | Dynamic evolution of herbivore-induced sesquiterpene biosynthesis in sorghum and related grass crops |
| Author(s): | Zhuang X; Kollner TG; Zhao N; Li G; Jiang Y; Zhu L; Ma J; Degenhardt J; Chen F; |
| Address: | "Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA" |
| DOI: | 10.1111/j.1365-313X.2011.04771.x |
| ISSN/ISBN: | 1365-313X (Electronic) 0960-7412 (Linking) |
| Abstract: | "Sorghum (Sorghum bicolor) plants damaged by insects emit a blend of volatiles, predominantly sesquiterpenes, that are implicated in attracting natural enemies of the attacking insects. To characterize sesquiterpene biosynthesis in sorghum, seven terpene synthase (TPS) genes, SbTPS1 through SbTPS7, were identified based on their evolutionary relatedness to known sesquiterpene synthase genes from maize and rice. While SbTPS6 and SbTPS7 encode truncated proteins, all other TPS genes were determined to encode functional sesquiterpene synthases. Both SbTPS1 and SbTPS2 produced the major products zingiberene, beta-bisabolene and beta-sesquiphellandrene, but with opposite ratios of zingiberene to beta-sesquiphellandrene. SbTPS3 produced (E)-alpha-bergamotene and (E)-beta-farnesene. SbTPS4 formed (E)-beta-caryophyllene as the major product. SbTPS5 produced mostly (E)-alpha-bergamotene and (Z)-gamma-bisabolene. Based on the genome sequences of sorghum, maize and rice and the sesquiterpene synthase genes they contain, collinearity analysis identified the orthologs of sorghum sesquiterpene synthase genes, except for SbTPS4, in maize and rice. Phylogenetic analysis implied that SbTPS1, SbTPS2 and SbTPS3, which exist as tandem repeats, evolved as a consequence of local gene duplication in a lineage-specific manner. Structural modeling and site-directed mutagenesis experiments revealed that three amino acids in the active site play critical roles in defining product specificity of SbTPS1, SbTPS2, SbTPS3 and their orthologs in maize and rice. The naturally occurring functional variations of sesquiterpene synthases within and between species suggest that multiple mechanisms, including lineage-specific gene duplication, subfunctionalization, neofunctionalization and pseudogenization of duplicated genes, have all played a role in the dynamic evolution of insect-induced sesquiterpene biosynthesis in grasses" |
| Keywords: | "Alkyl and Aryl Transferases/*genetics/*metabolism Animals *Biological Evolution Bridged Bicyclo Compounds/metabolism Catalytic Domain Gene Duplication *Herbivory Insecta/physiology Monocyclic Sesquiterpenes Mutagenesis, Site-Directed Oryza/enzymology/gene;" |
| Notes: | "MedlineZhuang, Xiaofeng Kollner, Tobias G Zhao, Nan Li, Guanglin Jiang, Yifan Zhu, Liucun Ma, Jianxin Degenhardt, Jorg Chen, Feng eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. England 2011/09/02 Plant J. 2012 Jan; 69(1):70-80. doi: 10.1111/j.1365-313X.2011.04771.x. Epub 2011 Oct 13" |
