Technologies for rapid cloning and characterization of resistance genes in wild and domesticated wheat.

Ghosh, Sreya (2020) Technologies for rapid cloning and characterization of resistance genes in wild and domesticated wheat. Doctoral thesis, University of East Anglia.

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Abstract

Wheat is a major worldwide staple, accounting for approximately 20% of the global calorie and protein consumption. Therefore, breeding wheat to maintain yields and increase them to match expected future demand is important for global food security. Biotic stresses pose a major constraint to wheat cultivation, in particular fungal pathogens such as the wheat rusts. Achieving durable genetic resistance to these pathogens would sustainably mitigate yield losses, but a lack of precise molecular markers for resistance genes can complicate their characterization and practical use in breeding programs. On the other hand, efforts to identify the molecular sequences of genes underlying resistance using forward genetics are hampered by the large genome size of wheat and its long generation time. In this thesis, I discuss the establishment of a rapid generation advancement protocol, called “Speed Breeding”, that can be used to significantly reduce the generation time of wheat, while ensuring usability for pre-breeding and research activities. I further use a model based on binomial distribution to determine an approximate number of allelic trait-mutants required to identify a causal gene through sequence comparison, to establish best practices for identifying genes through mutational genomics. I then discuss how I have identified two novel gene candidates that confer resistance to the globally devasting wheat leaf rust pathogen in the wheat wild relative Aegilops tauschii, using k-mer based association genetics. The identification of the molecular sequences of resistance genes provides the opportunity to perform precise experiments to gain a mechanistic understanding of the genes’ function and their behaviour in different genetic backgrounds, while speed breeding can play an important role in shortening the timeline of such experiments. At the same time, the sequence information is useful for breeders to develop gene-specific markers to trace the gene in their germplasm and breeding programs.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	29 Mar 2023 09:21
Last Modified:	29 Mar 2023 09:21
URI:	https://ueaeprints.uea.ac.uk/id/eprint/91702
DOI:

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