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Document Type

Dissertation - University Access Only

Award Date

2014

Degree Name

Doctor of Philosophy (PhD)

Department / School

Biology and Microbiology

First Advisor

Jai S. Rohila

Abstract

Wheat (Triticum spp.) is one of the world’s most important food crops in terms of harvested area, trade value, and human nutrition. A sharp decline in the availability of arable land, sufficient supply of irrigation water, hotter crop growing seasons along with a continuous steep increase in food demands have exerted a pressure on farmers to produce more grains with fewer resources. A combinatorial approach of accelerated gene discovery through genomics, proteomics, metabolomics and other associated -omics is proving to be an effective way to speed up the wheat improvement programs worldwide. During this study, 21 germplasm (14 from Egypt, 6 from USA, and 1 from CIMMYT) were screened for drought and heat tolerance using 4 different research platforms. The Egyptian and CIMMYT germplasm resembled the tolerant group while the American germplasm resembled towards susceptible group. The analysis of the physiological responses revealed that leaf water potential, net photosynthesis, evapotranspiration, and stomatal conductance for the tolerant group stays at comparatively higher levels than that of the susceptible ones. Four germplasm were chosen for transcriptomics and metabolomics analysis, three belonging to the tolerant group and one belonging to the susceptible group. The transcriptomics studies showed that the tolerant group up regulates the expression of photosynthesis related genes which come in coherence with the physiological analysis. Also, abscisic acid, jasmonic acid, redox genes and stress related transcription factors were found differentially regulated under stress in both susceptible and the tolerant groups. The metabolomics platform revealed that the tolerant group shows a delayed response for increasing some metabolites related to drought and heat stress. The CIMMYT germplasm was chosen for proteomics analysis, which revealed that a strong heat shock-redox system might be a very important reason giving the wheat germplasm tolerance to drought and heat stress. Apart from this, two contrasting near isogenic lines (NILs) for Fusarium head blight resistance; 260-2 (resistant) and 260-4 (susceptible), were also analyzed using proteomics platform. The analysis revealed that there are at least 7 proteins which could have roles in the Fusarium head blight resistance, since they were uniquely regulated between the resistant 260-2 and the susceptible 260-4 NIL.

Library of Congress Subject Headings

Wheat -- Effect of stress on
Wheat -- Drought tolerance
Wheat -- Effect of heat on
Wheat -- Molecular genetics

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

364

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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