title: Transgenic studies on the involvement of cytokinin and gibberellin in male development.
abstract: Numerous plant hormones interact during plant growth and development. Elucidating the role of these various hormones on particular tissue types or developmental stages has been difficult with exogenous applications or constitutive expression studies. Therefore, we used tissue-specific promoters expressing CKX1 and gai, genes involved in oxidative cytokinin degradation and gibberellin (GA) signal transduction, respectively, to study the roles of cytokinin and GA in male organ development. Accumulation of CKX1 in reproductive tissues of transgenic maize (Zea mays) resulted in male-sterile plants. The male development of these plants was restored by applications of kinetin and thidiazuron. Similarly, expression of gai specifically in anthers and pollen of tobacco (Nicotiana tabacum) and Arabidopsis resulted in the abortion of these respective tissues. The gai-induced male-sterile phenotype exhibited by the transgenic plants was reversible by exogenous applications of kinetin. Our results provide molecular evidence of the involvement of cytokinin and GA in male development and support the hypothesis that the male development is controlled in concert by multiple hormones. These studies also suggest a potential method for generating maintainable male sterility in plants by using existing agrochemicals that would reduce the expense of seed production for existing hybrid crops and provide a method to produce hybrid varieties of traditionally non-hybrid crops.
authors.affiliation: Mystic Research, Monsanto Company, St Louis, Missouri 63198, USA. shihshieh.huang@na1.monsanto.com
authors.forename: Shihshieh
authors.initials: S
authors.lastname: Huang
authors.forename: R Eric
authors.initials: RE
authors.lastname: Cerny
authors.forename: Youlin
authors.initials: Y
authors.lastname: Qi
authors.forename: Deepti
authors.initials: D
authors.lastname: Bhat
authors.forename: Carrie M
authors.initials: CM
authors.lastname: Aydt
authors.forename: Doris D
authors.initials: DD
authors.lastname: Hanson
authors.forename: Kathleen P
authors.initials: KP
authors.lastname: Malloy
authors.forename: Linda A
authors.initials: LA
authors.lastname: Ness
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D003583:Cytokinins / Q000494:pharmacology*; D005298:Fertility / Q000235:genetics / Q000502:physiology; D035264:Flowers / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005875:Gibberellins / Q000494:pharmacology*; D007701:Kinetin; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010671:Phenylurea Compounds / Q000494:pharmacology; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D011058:Pollen / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D013830:Thiadiazoles; D014026:Nicotiana / Q000235:genetics; D003313:Zea mays / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development
chemical_list: D029681:Arabidopsis Proteins; D003583:Cytokinins; C109555:GAI protein, Arabidopsis; D005875:Gibberellins; D010671:Phenylurea Compounds; D013830:Thiadiazoles; C016785:thidiazuron; D010088:Oxidoreductases; C019984:cytokinin oxidase; D000225:Adenine; D007701:Kinetin