Multitrophic secondary metabolite s mediated defense in zingiber zerumbet l smith a systematic exploration using molecular metabolomic and microbiome analysis

Abstract

Zingiber zerumbet is a perennial rhizomatous herb with wide range of ethnomedicinal newlineuses and found in wild or naturalized states throughout Southeast Asia, Pacific and newlineOceania. Despite the remarkable biotic resistance exhibited by Z. zerumbet, obscure newlineinformation is available on the defense mechanisms employed by this wild taxon newlineto prevent pathogenic ingress especially with respect to Pythium myriotylum, an newlineeconomically significant necrotrophic phytopathogen. Present study is a novel newlineattempt in this direction towards understanding the role of secondary metabolites newlinein mediating defense mechanisms in Z. zerumbet. Among the sixty-nine newlineconstituents identified in essential oil of Z. zerumbet, the sesquiterpenoid, newline zerumbone [2,6,9,9-tetramethyl-(2E,6E,10E)- cycloundeca-2,6,10-trien-1-one] is the newlineactive principle. Sesquiterpenoids (C15) constitute a large group of isoprenoid (C5) newlinecompounds with diverse physiological, metabolic and structural functions. Biosynthesis newlineof diverse terpenoid carbon skeleton is catalyzed by terpene synthases (TPS) that newlineconstitutes a mid-size family with gene numbers ranging from ca 20-150 as observed in newlinesequenced plant genomes. TPS genes share a common evolutionary origin and newlineresult from multiple gene duplication and diversification events. One of the newlinerationales of present study involves isolation and characterization of TPS gene newlinesequence from Z. zerumbet and to deduce the correlation between TPS gene newlineexpression and biotic resistance to soft-rot causative P. myriotylum. Following 5 newlineand 3 genome walking strategy, a full-length TPS homologous sequence newlinedesignated ZzTPS was identified. Isolated ZzTPS gene showed identity ranging from newline37% to terpene synthase [Macleaya cordata] (e-value: 8e-22) to75% to chloroplast newlinelinalool synthase [Hedychium coronarium] (e-value: 5e-43) following NCBI newlinesearches. ZzTPS gene contains an intact open reading frame (ORF) of 1218 bp newlinelength and the deduced translated protein had 405 amino acids.