Dissertation
UNDERSTANDING THE ROLE OF AUXIN AND ITS TRANSPORT IN CONTROLLING WHEAT DEVELOPMENT
Doctor of Philosophy (PhD), Washington State University
01/2017
Handle:
https://hdl.handle.net/2376/117147
Abstract
Genes influencing plant height have revolutionized agriculture in the late 1960s by almost doubling the wheat and rice production. These Rht genes in wheat and rice encode proteins that modulate the signaling pathway of phytohormone gibberellins (GA). Fifty years on, with more pronounced climate changes, ill effects of these genes on early plant growth traits have surfaced. Concomitant with the creation and screening of functional genomic resources in wheat, agronomically relevant reduction in plant height can be achieved by modulating genes involved in auxin pathway. Dynamic and differential distribution of auxin carried out by the coordinated activities of auxin influx and efflux transport proteins drives several aspects of plant development. PIN proteins form an integral component of the auxin efflux system. Therefore, the overall goal of this project was to create an alternate dwarfing system in wheat by modulating the PIN-mediated auxin transport pathway. Here, we have structurally and functionally characterized orthologs and paralogs of Arabidopsis PIN1 gene in wheat TaPIN1, and have achieved 26% height reduction upon its transient silencing. We also report the identification and structural characterization of 15 other PIN gene family members in hexaploid wheat and its progenitors showing distribution on six chromosomes. Analyses of the predicted PIN protein sequences from wheat and their orthologs from other species revealed motifs that distinguished various PIN loci from each other. Quantification of the reverse growth patterns of coleoptile and leaf in wheat suggested probable role of the motif-dependent localization of PINs. Expression analysis revealed organ and stage specific gene expression patterns for wheat PIN family. Potential members of this gene family particularly PIN8 were identified that can be utilized to improve wheat architecture. Creation of functional genomic resource was combined with high throughput bioinformatics analysis to identify desirable mutants. In total, 14,130 mutational changes were detected. On an average, 662 SNPs and 10 small INDELs were identified for each of the mutants. A mutation frequency of one per 5 Kb was observed with 70% being transitions and 30% transversions. Genes present in the distal regions of the chromosomes were found to be more prone to EMS-induced changes.
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Details
- Title
- UNDERSTANDING THE ROLE OF AUXIN AND ITS TRANSPORT IN CONTROLLING WHEAT DEVELOPMENT
- Creators
- Gaganjot Sidhu
- Contributors
- Kulvinder S Gill (Advisor)Ananth Kalyanaraman (Committee Member)Arron Carter (Committee Member)Linda Thomashow (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Crop and Soil Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 226
- Identifiers
- 99900581429001842
- Language
- English
- Resource Type
- Dissertation