title: Disruption of OPR7 and OPR8 reveals the versatile functions of jasmonic acid in maize development and defense.
abstract: Here, multiple functions of jasmonic acid (JA) in maize (Zea mays) are revealed by comprehensive analyses of JA-deficient mutants of the two oxo-phytodienoate reductase genes, OPR7 and OPR8. Single mutants produce wild-type levels of JA in most tissues, but the double mutant opr7 opr8 has dramatically reduced JA in all organs tested. opr7 opr8 displayed strong developmental defects, including formation of a feminized tassel, initiation of female reproductive buds at each node, and extreme elongation of ear shanks; these defects were rescued by exogenous JA. These data provide evidence that JA is required for male sex determination and suppression of female reproductive organ biogenesis. Moreover, opr7 opr8 exhibited delayed leaf senescence accompanied by reduced ethylene and abscisic acid levels and lack of anthocyanin pigmentation of brace roots. Remarkably, opr7 opr8 is nonviable in nonsterile soil and under field conditions due to extreme susceptibility to a root-rotting oomycete (Pythium spp), demonstrating that these genes are necessary for maize survival in nature. Supporting the importance of JA in insect defense, opr7 opr8 is susceptible to beet armyworm. Overall, this study provides strong genetic evidence for the global roles of JA in maize development and immunity to pathogens and insects.
authors.affiliation: Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: Yuanxin
authors.initials: Y
authors.lastname: Yan
authors.forename: Shawn
authors.initials: S
authors.lastname: Christensen
authors.forename: Tom
authors.initials: T
authors.lastname: Isakeit
authors.forename: Jürgen
authors.initials: J
authors.lastname: Engelberth
authors.forename: Robert
authors.initials: R
authors.lastname: Meeley
authors.forename: Allison
authors.initials: A
authors.lastname: Hayward
authors.forename: R J Neil
authors.initials: RJ
authors.lastname: Emery
authors.forename: Michael V
authors.initials: MV
authors.lastname: Kolomiets
mesh_terms: D000483:Alleles; D000818:Animals; D000872:Anthocyanins / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism*; D004251:DNA Transposable Elements / Q000235:genetics; D060467:Disease Resistance / Q000276:immunology; D017343:Genes, Plant / Q000235:genetics; D060434:Herbivory / Q000502:physiology; D016254:Mutagenesis, Insertional / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D009928:Organ Specificity; D054883:Oxylipins / Q000378:metabolism*; D010641:Phenotype; D010858:Pigmentation; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D018515:Plant Leaves / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018520:Plant Shoots / Q000254:growth & development; D011775:Pythium / Q000502:physiology; D018411:Spodoptera / Q000502:physiology; D003313:Zea mays / Q000235:genetics / Q000254:growth & development* / Q000276:immunology* / Q000382:microbiology
chemical_list: D000872:Anthocyanins; D003517:Cyclopentanes; D004251:DNA Transposable Elements; D054883:Oxylipins; D010940:Plant Proteins; C011006:jasmonic acid