title: Water deficit stress tolerance in maize conferred by expression of an isopentenyltransferase (IPT) gene driven by a stress- and maturation-induced promoter.
abstract: Senescence can be delayed in transgenic plants overexpressing the enzyme isopentenyltransferase (IPT) due to stress-induced increased levels of endogenous cytokinins. This trait leads to sustained photosynthetic activity and improved tolerance to abiotic stress. The aim of this study was to generate and characterize transgenic plants of maize (Zea mays L.) transformed with the IPT gene sequence under the regulation of SARK promoter (protein kinase receptor-associated senescence). Three independent transgenic events and their segregating null controls were evaluated in two watering regimes (WW: well watered; WD: water deficit) imposed for two weeks around anthesis. Our results show that the WD treatment induced IPT expression with the concomitant increase in cytokinin levels, which prolonged the persistence of total green leaf area, and maintained normal photosynthetic rate and stomatal conductance. These trends were accompanied by a minor decrease in number of grains per plant, individual grain weight and plant grain yield as compared to WW plants. Plants expressing the IPT gene under WD had PGR, anthesis and silking dates and biomass levels similar to WW plants. Our results demonstrate that expression of the IPT gene under the regulation of the SARK promoter helps improve productivity under WD conditions in C4 plants like maize.
authors.affiliation: Institute of Genetics "Edwald A. Favret", National Institute of Agricultural Technology (INTA), Buenos Aires, Argentina. Electronic address: decimaoneto.cecilia@inta.gob.ar.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Décima Oneto
authors.affiliation: School of Agriculture of the University of Buenos Aires, Argentina,; National Scientific and Technical Research Council (CONICET), Argentina;
authors.forename: María Elena
authors.initials: ME
authors.lastname: Otegui
authors.affiliation: Institute of Genetics "Edwald A. Favret", National Institute of Agricultural Technology (INTA), Buenos Aires, Argentina; National Scientific and Technical Research Council (CONICET), Argentina;
authors.forename: Irene
authors.initials: I
authors.lastname: Baroli
authors.affiliation: Institute of Genetics "Edwald A. Favret", National Institute of Agricultural Technology (INTA), Buenos Aires, Argentina; National Scientific and Technical Research Council (CONICET), Argentina;
authors.forename: Ailin
authors.initials: A
authors.lastname: Beznec
authors.affiliation: Institute of Genetics "Edwald A. Favret", National Institute of Agricultural Technology (INTA), Buenos Aires, Argentina.
authors.forename: Paula
authors.initials: P
authors.lastname: Faccio
authors.affiliation: Institute of Genetics "Edwald A. Favret", National Institute of Agricultural Technology (INTA), Buenos Aires, Argentina.
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Bossio
authors.affiliation: Department Plant Sciences, University of California, Davis, USA.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Blumwald
authors.affiliation: Institute of Genetics "Edwald A. Favret", National Institute of Agricultural Technology (INTA), Buenos Aires, Argentina.
authors.forename: Dalia
authors.initials: D
authors.lastname: Lewi
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D019883:Alkyl and Aryl Transferases / Q000235:genetics* / Q000378:metabolism; D018533:Biomass; D015139:Blotting, Southern / Q000379:methods; D002734:Chlorophyll / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D003583:Cytokinins / Q000378:metabolism; D003681:Dehydration / Q000235:genetics / Q000378:metabolism*; D002523:Edible Grain / Q000254:growth & development; D054883:Oxylipins / Q000378:metabolism; D010788:Photosynthesis; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D054046:Plant Stomata; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction / Q000379:methods; D011401:Promoter Regions, Genetic; D012987:Soil / Q000737:chemistry; D013312:Stress, Physiological; D014867:Water / Q000378:metabolism; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development
chemical_list: D003517:Cyclopentanes; D003583:Cytokinins; D054883:Oxylipins; D010940:Plant Proteins; D012987:Soil; D014867:Water; D002734:Chlorophyll; C011006:jasmonic acid; D000040:Abscisic Acid; D019883:Alkyl and Aryl Transferases; C024274:adenylate isopentenyltransferase
keywords: C(4) plants; Cytokinins; Genetic transformation; Plant grain yield; Water stress tolerance; Zea mays L.