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Title:Analysis of Aba-Regulated Gene Expression in Normal and Viviparous Maize (Zea Mays L.) Embryos
Author(s):Paiva, Renato
Doctoral Committee Chair(s):Kriz, Alan L.
Department / Program:Agronomy
Discipline:Agronomy
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Agriculture, Agronomy
Biology, Molecular
Biology, Plant Physiology
Abstract:Numerous studies have demonstrated that the phytohormone abscisic acid (ABA) plays an important role in many processes during seed development. ABA prevents precocious germination during seed development and induces specific genes normally expressed during other stages of seed development. The availability of maize viviparous mutants which are defective in ABA biosynthesis allowed the investigation of varying physiological ABA levels on expression patterns of specific ABA-responsive genes. The present work indicated that the expression of several ABA-responsive genes is variable among the different viviparous mutants. Among the genes examined, Em showed the highest correlation between in situ ABA content and transcript levels. Results from ABA studies strongly support the positive role of this phytohormone in inducing Globulin (Glb1 and Glb2) gene expression in maize embryos. However, the in situ ABA levels obtained from sib normal and viviparous mutant embryos do not correspond to the increase in Globulin expression in these mutants. Neither Glb1, Glb2, nor Em transcripts are detected in vp1 mutant embryos suggesting that a functional Vp1 gene product is required for Globulin and Em gene expression. These studies indicate that Globulin gene expression in maize embryos is under the control of different factors which require at least the combination of in situ ABA levels and the presence of a functional Vp1 gene product. This study represents a unique case in which ABA levels in specific ABA-deficient mutants are compared with expression patterns of developmentally-regulated ABA-responsive genes.
Issue Date:1993
Type:Text
Description:117 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1993.
URI:http://hdl.handle.net/2142/72614
Other Identifier(s):(UMI)AAI9329128
Date Available in IDEALS:2014-12-17
Date Deposited:1993


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