Effect of Chromatin modification on meiosis: wheat, a model for polyploid crops

Lead Research Organisation: Earlham Institute
Department Name: UNLISTED

Abstract

Most related chromosomes of wild relatives of wheat exhibit extensive gene synteny along their chromosome length. Moreover the genes on related chromosomes exhibit more than 95% homology at the sequence level. Despite this level of similarity, there is little recombination between wild relative and wheat chromosomes at meiosis due the presence of the Ph1 locus. This project aims to identify and understand the major chromosome pairing (Ph1) locus in wheat and its control of chromosome pairing. Wheat breeding programmes that exploit the genetic variation available in wild relatives provide potential opportunities for increases in yield production. Such a strategy can result in the transfer of a range of genes from alien species into wheat that control target traits such as increased tolerance/resistance to drought, salt, aluminium, disease, insect damage and the introduction of perenniality. One of the major barriers to exploiting wild relatives involves deploying more efficiently the Ph1 system to induce pairing and recombination between related chromosomes. By utilising next generation sequencing and cell biological approaches, we will identify what is being altered in the genic regions by the presence or absence of Ph1 at the onset of meiosis. We will access whether there is altered distribution of double strand breaks or their processing, chromatin structure or methylation of and transcription from the genic regions. From this information, we will treat developing wheat anthers prior to meiosis with drugs which themselves induce similar changes and then score the resulting effects on chromosome pairing during metaphase I, to confirm the association of the particular change with a pairing effect. The expected outcome of this project includes the creation of tools to allow breeders to have access to the genetic potential of wild wheat species that possess non-collinear chromosomes and which cannot normally be introgressed into wheat.

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