Item – Theses Canada

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OCLC number
732947834
Link(s) to full text
LAC copy
LAC copy
Author
Challa, Sathya Sheela.
Title
Genetic and phenotypic analysis of the HUA2-LIKE (HULK) gene family in Arabidopsis thaliana.
Degree
Ph. D. -- University of Western Ontario, 2009
Publisher
Ottawa : Library and Archives Canada = Bibliothèque et Archives Canada, [2010]
Description
3 microfiches
Notes
Includes bibliographical references.
Abstract
This thesis describes the functional characterization of four members of a small plant-specific 'HULK' gene family in 'Arabidopsis thaliana'. Gene expression studies indicated that four 'HULK ' genes display similar expression patterns but one of them is expressed at a low level. Phenotypic analysis of plants carrying mutations in one or several 'HULK' family genes revealed that they affect flowering time, embryo development, pollen viability, fertility and plant size. Only mutations in the 'HUA2' gene cause a visible phenotype, whereas ' hulk1, hulk2' and 'hulk3' mutants appear similar to wild type. The loss-of-function 'hua2-7' allele combined with ' hulk1, hulk2' or 'hulk3' alleles causes early flowering. In addition, 'hua2-7/hulk1' double mutants show sterility in early flowers and embryo defects. The 'hulk2/hulk3' mutants are late flowering, whereas 'hulk1/hulk2' and 'hulk1/hulk3 ' double mutants resemble wild type plants. The early and late flowering phenotypes of several 'hulk' mutants are correlated with ' FLC' transcript levels. The expressions of wild type 'HULK ' genes in single and double mutants are altered, signifying the complexity of the molecular changes in these genetic backgrounds. The embryo defects and sterile flower phenotype were gradually enhanced when additional ' HULK' family genes were compromised revealing an extensive functional redundancy among the 'HULK' genes. The 'hua2-7/hulk1 ' mutant in combination with 'hulk2' enhances the embryo defect phenotype, and with 'hulk3' causes male sterility due to loss of pollen viability. I was unable to recover the mutant lacking all four H'HULK' genes. Through over-expression analysis, ' HULK' genes exhibited a series of developmental phenotypes, including delay in floral transition, serrated leaves and sterile flowers. Taken together, the results presented in this thesis have established essential roles of ' HULK' genes in plant development.
ISBN
9780494542750
0494542756