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Plant Physiol

Title:		"Discovery, Biosynthesis and Stress-Related Accumulation of Dolabradiene-Derived Defenses in Maize"
Author(s):		Mafu S; Ding Y; Murphy KM; Yaacoobi O; Addison JB; Wang Q; Shen Z; Briggs SP; Bohlmann J; Castro-Falcon G; Hughes CC; Betsiashvili M; Huffaker A; Schmelz EA; Zerbe P;
Address:		"Department of Plant Biology, University of California, Davis, California. Section of Cell and Developmental Biology, University of California, La Jolla, California. Department of Chemistry, San Diego State University, San Diego, California. College of Agronomy and Institute of Ecological Agriculture, Sichuan Agricultural University, Chengdu 611130, China. Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4. Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, La Jolla, California. Department of Plant Biology, University of California, Davis, California pzerbe@ucdavis.edu"
Journal Title:		Plant Physiol
Year:		2018
Volume:		20180223
Issue:		4
Page Number:		2677 - 2690
DOI:		10.1104/pp.17.01351
ISSN/ISBN:		1532-2548 (Electronic) 0032-0889 (Print) 0032-0889 (Linking)
Abstract:		"Terpenoids are a major component of maize (Zea mays) chemical defenses that mediate responses to herbivores, pathogens, and other environmental challenges. Here, we describe the biosynthesis and elicited production of a class of maize diterpenoids, named dolabralexins. Dolabralexin biosynthesis involves the sequential activity of two diterpene synthases, ENT-COPALYL DIPHOSPHATE SYNTHASE (ZmAN2) and KAURENE SYNTHASE-LIKE4 (ZmKSL4). Together, ZmAN2 and ZmKSL4 form the diterpene hydrocarbon dolabradiene. In addition, we biochemically characterized a cytochrome P450 monooxygenase, ZmCYP71Z16, which catalyzes the oxygenation of dolabradiene to yield the epoxides 15,16-epoxydolabrene (epoxydolabrene) and 3beta-hydroxy-15,16-epoxydolabrene (epoxydolabranol). The absence of dolabradiene and epoxydolabranol in Zman2 mutants under elicited conditions confirmed the in vivo biosynthetic requirement of ZmAN2. Combined mass spectrometry and NMR experiments demonstrated that much of the epoxydolabranol is further converted into 3beta,15,16-trihydroxydolabrene (trihydroxydolabrene). Metabolite profiling of field-grown maize root tissues indicated that dolabralexin biosynthesis is widespread across common maize cultivars, with trihydroxydolabrene as the predominant diterpenoid. Oxidative stress induced dolabralexin accumulation and transcript expression of ZmAN2 and ZmKSL4 in root tissues, and metabolite and transcript accumulation were up-regulated in response to elicitation with the fungal pathogens Fusarium verticillioides and Fusarium graminearum Consistently, epoxydolabranol significantly inhibited the growth of both pathogens in vitro at 10 microg mL(-1), while trihydroxydolabrene-mediated inhibition was specific to Fverticillioides These findings suggest that dolabralexins have defense-related roles in maize stress interactions and expand the known chemical space of diterpenoid defenses as genetic targets for understanding and ultimately improving maize resilience"
Keywords:		"Alkyl and Aryl Transferases/genetics/metabolism *Biosynthetic Pathways Disease Resistance/genetics Diterpenes/chemistry/*metabolism Fusarium/classification/physiology Gene Expression Regulation, Plant Molecular Structure Plant Diseases/genetics/microbiolo;"
Notes:		"MedlineMafu, Sibongile Ding, Yezhang Murphy, Katherine M Yaacoobi, Omar Addison, J Bennett Wang, Qiang Shen, Zhouxin Briggs, Steven P Bohlmann, Jorg Castro-Falcon, Gabriel Hughes, Chambers C Betsiashvili, Mariam Huffaker, Alisa Schmelz, Eric A Zerbe, Philipp eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2018/02/25 Plant Physiol. 2018 Apr; 176(4):2677-2690. doi: 10.1104/pp.17.01351. Epub 2018 Feb 23"