TitlePhysiological, biochemical, and molecular mechanisms associated with drought tolerance in agrostis species
NameMerewitz, Emily B. (author), Huang, Bingru (chair), Gianfagna, Thomas (internal member), Bonos, Stacy (internal member), Da Costa, Michelle (outside member), Rutgers University, Graduate School - New Brunswick,
DescriptionImprovement of the drought stress tolerance of plants is necessary due to the widespread incidence of drought damage to crop species. Turfgrasses are susceptible to drought damage and may exhibit symptoms of cellular water loss such as wilting, cessation of growth, and other cellular damages resulting in leaf and root senescence. Creeping bentgrass (Agrostis stolonifera L.) is a high value, drought sensitive turfgrass crop species. The main goals of the research described in this thesis were to evaluate mechanisms responsible for drought tolerance in turfgrasses by evaluating whole-plant, cellular, proteomic, metabolomic, genetic, and genomic regions associated with drought defense responses. Part I will focus on how differential hormonal regulation may affect the drought defense responses in turfgrasses. Plant hormones such as cytokinins (CK) are signaling molecules controlling gene expression and the activity of various biochemical pathways. Differential drought-induced regulation of plant hormones is a primary response to prevent cellular desiccation. Drought injury symptoms have been associated with an inhibition in CK synthesis and maintenance of endogenous CK is associated with alleviation of drought damage. Thus, specific objectives related to the effect of elevated CK content in creeping bentgrass during drought stress on 1) whole-plant physiology 2) proteomic 3) metabolic and 4) genetic responses were evaluated. Elevated CK content in the creeping bentgrass plants was achieved by drought induced expression of an ipt transgene encoding the enzyme adenine isopentenyltransferase promoting CK synthesis. The results showed significant modifications of the gene, protein, and metabolite profiles were caused by elevated CK, particularly changes related to energy production, metabolism, and stress defense. Part II will focus on the identification of genomic regions associated with drought tolerance known as quantitative trait loci (QTL). QTL are large genomic regions that are associated with molecular markers and specific plant phenotypes that can be used in plant breeding strategies. Knowledge of the location of QTLs can help breeders screen large quantities of germplasm for complex traits such as drought tolerance. QTLs for important drought tolerance traits such as relative water content, cellular membrane stability, indexes of turf quality, leaf area, and chlorophyll content were found.
NoteIncludes bibliographical references
Noteby Emily B. Merewitz
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.