Location: Chemistry ResearchTitle: Biosynthesis, elicitation and roles of monocot terpenoid phytoalexins Author
Submitted to: Plant Journal
Publication Type: Review Article
Publication Acceptance Date: 1/17/2014
Publication Date: 8/1/2014
Citation: Schmelz, E.A., Huffaker, A., Sims, J.W., Christensen, S.A., Lu, X., Okada, K., Peters, R. 2014. Biosynthesis, elicitation and roles of monocot terpenoid phytoalexins. Plant Journal. 79:659-678. Interpretive Summary:
Technical Abstract: A long standing goal in plant defense research is to optimize the protective function of biochemicals that impede pathogen and pest attack. Nearly 40 years ago pathogen-inducible non-volatile diterpenoids were described in rice and demonstrated to function as potent antimicrobial phytoalexins. Using rice and maize as examples, we discuss recent advances in the identification, biosynthesis, elicitation, signaling and function of inducible terpenoid phytoalexins. The rate of monocot terpenoid phytoalexin discovery in additional species is likely to increase through recent advances in sequencing and annotation that are uncovering cereal genes displaying inducible transcript accumulation for previously uncharacterized terpene synthases. Genetic evidence suggests that terpenoid phytoalexins may occur widely in key cereal crops and should aid in discoveries outside of the Poaceae. Biochemical discoveries are actively pairing terpenoid phytoalexin precursors and endproducts with cognate biosynthetic pathway genes. In addition to classical antimicrobial functions, examples of root exudate-mediated allelopathy and insect-elicitation coupled with antifeedant activity encourage a consideration of additional ecological roles for phytoalexins that blur traditionally discrete classifications. Critical examination of these biological roles is aided by the establishment of rice and maize mutant collections and genetic transformation. Collectively these approaches enable the additional examination of terpenoid phytoalexin precursors and endproducts as potential signals mediating further plant physiological processes.