Graduate Studies
First Advisor
Harkamal Walia
Second Advisor
Scott E. Sattler
Date of this Version
11-2024
Document Type
Thesis
Citation
A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science
Major: Agronomy
Under the supervision of Professors Harkamal Walia and Scott E. Sattler
Lincoln, Nebraska, November 2024
Abstract
Increased frequency of extreme weather events threatens global food security. Developing resilient climate smart cultivars requires an integrated multi-omics based approach where abiotic stress response in crop plants is accurately recorded and the underlying molecular and physiological mechanisms can be elucidated. With access to diverse techniques and plant materials from Dr. Sattler’s and Dr. Walia’s laboratories, this study addresses the physiological and molecular responses of sorghum to water limitation.
In sorghum, caffeic acid O-methyltransferase (COMT) is central for the biosynthesis of one of the three monolignols. The mechanistic role of COMT in root growth and plant stress response was explored in this work using analysis of metabolomic and transcriptome data from sorghum whole root tissue. This integrated approach suggested the enrichment of defense related compounds and free amino acids in the root tissue from plants of the loss of function mutant brown midrib (bmr) 12, that could attribute to its enhanced stress tolerance. Conversely, the altered root phenotype in bmr12 could be attributed to increased levels of an auxin antagonist IAA-Trp.
This study was further extended to explore the altered spectral differences among the bmr mutants in response to water limitation, using hyperspectral imaging (HSI) (650 -1650 nm). The results from this study suggested that bmr mutants have altered spectral responses, which could be attributed to differences in energy concentration of the samples. The models trained for analysis provide a set of wavelengths with the highest predictive value for calorimetric content, which can be applied to high-throughput genomics-assisted breeding strategies for sorghum.
Advisors: Harkamal Walia and Scott E. Sattler
Comments
Copyright 2024, Yuvraj Chopra. Used by permission