title: A Wheat Cinnamyl Alcohol Dehydrogenase TaCAD12 Contributes to Host Resistance to the Sharp Eyespot Disease.
abstract: Sharp eyespot, caused mainly by the necrotrophic fungusRhizoctonia cerealis, is a destructive disease in hexaploid wheat (Triticum aestivumL.). InArabidopsis, certain cinnamyl alcohol dehydrogenases (CADs) have been implicated in monolignol biosynthesis and in defense response to bacterial pathogen infection. However, little is known about CADs in wheat defense responses to necrotrophic or soil-borne pathogens. In this study, we isolate a wheat CAD geneTaCAD12in response toR. cerealisinfection through microarray-based comparative transcriptomics, and study the enzyme activity and defense role of TaCAD12 in wheat. The transcriptional levels ofTaCAD12in sharp eyespot-resistant wheat lines were significantly higher compared with those in susceptible wheat lines. The sequence and phylogenetic analyses revealed that TaCAD12 belongs to IV group in CAD family. The biochemical assay proved that TaCAD12 protein is an authentic CAD enzyme and possesses catalytic efficiencies toward both coniferyl aldehyde and sinapyl aldehyde. Knock-down ofTaCAD12transcript significantly repressed resistance of the gene-silenced wheat plants to sharp eyespot caused byR. cerealis, whereasTaCAD12overexpression markedly enhanced resistance of the transgenic wheat lines to sharp eyespot. Furthermore, certain defense genes (Defensin, PR10, PR17c, andChitinase1) and monolignol biosynthesis-related genes (TaCAD1, TaCCR, andTaCOMT1) were up-regulated in theTaCAD12-overexpressing wheat plants but down-regulated inTaCAD12-silencing plants. These results suggest that TaCAD12 positively contributes to resistance against sharp eyespot through regulation of the expression of certain defense genes and monolignol biosynthesis-related genes in wheat.
authors.affiliation: The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Rong
authors.affiliation: The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Meiying
authors.initials: M
authors.lastname: Luo
authors.affiliation: The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Tianlei
authors.initials: T
authors.lastname: Shan
authors.affiliation: The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Xuening
authors.initials: X
authors.lastname: Wei
authors.affiliation: The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Lipu
authors.initials: L
authors.lastname: Du
authors.affiliation: The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Huijun
authors.initials: H
authors.lastname: Xu
authors.affiliation: The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Zengyan
authors.initials: Z
authors.lastname: Zhang
keywords: Rhizoctonia cerealis; cinnamyl alcohol dehydrogenase (CAD); defense genes; hexaploid wheat; monolignol biosynthesis-related genes; sharp eyespot-resistance