Thesis
Regulators of seedling root-growth rate and characterization of SALPI in Brachypodium distachyon
Washington State University
Master of Science (MS), Washington State University
05/2019
DOI:
https://doi.org/10.7273/000004230
Handle:
https://hdl.handle.net/2376/125262
Abstract
Crop advancement has been greatly benefited by marker-assisted selection, next-generation sequencing, and genomics-based breeding methods which decrease selection time for breeding programs and aid in gene identification. These advancements have been particularly useful for quantitative traits, which underlie a number of agronomically important traits such as root growth and abiotic stress tolerance that have high impacts on crop yield. However, quantitative root traits are difficult to study due to obstruction by soil and the complexity of epistatic interactions. Globally, average temperatures have had an upward trend since the beginning of the twentieth century and are continuing to rise, resulting in intensification of abiotic stresses such as heat, drought, and salinity. Identification and integration of abiotic stress-responsive genes is critical for breeding high-yielding crops that are well-adapted for the predicted changing climate. Multi-method approaches are progressively accelerating this process, as well as the utilization of model species for comparative studies in genetically complex crops. Brachypodium distachyon is a model for temperate cereals which we used in Chapter 2 for the identification of a candidate gene regulating seedling root-growth rate. We used a modified QTL-Seq approach that encompassed QTL analysis, whole genome resequencing of a bulk segregant population, single nucleotide polymorphism (SNP) mapping, and expression analysis. Four QTL were identified on Chromosomes 1, 3, 4, and 5. Notably, the QTL located on chromosome 5 correlated with two SNPs located in the promoter of calmodulin-binding transcription activator 4 (CAMTA4). CAMTA4 had a 7-fold difference in transcript abundance between parental accessions that exhibit a 3-fold difference in seedling root-growth rate. In Chapter 3, we performed characterization of stress associated little protein 1 (SALP1) in B. distachyon, an abiotic stress-responsive gene found to confer salt tolerance in rice. Stable transgenic BdSALP1 lines were created for overexpression and knockdown analysis, whereas protein localization was visualized transiently in Nicotiana benthamiana. Together, these studies have shed light on genes involved in root-growth rate and abiotic stress tolerance; paving the way for future studies in related crops and examination of their importance for cereal breeding programs.
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Details
- Title
- Regulators of seedling root-growth rate and characterization of SALPI in Brachypodium distachyon
- Creators
- Zara B. York
- Contributors
- Karen Sanguinet (Advisor) - Washington State University, Crop and Soil Sciences, Department of
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900896424501842
- Language
- English
- Resource Type
- Thesis