Award details

Increasing genetic diversity in wheat by interfering with mismatch repair

Reference	BB/F001185/1
Principal Investigator / Supervisor	Professor Keith Edwards
Co-Investigators / Co-Supervisors
Institution	University of Bristol
Department	Biological Sciences
Funding type	Research
Value (£)	395,858
Status	Completed
Type	Research Grant
Start date	01/02/2008
End date	31/01/2012
Duration	48 months

Abstract

Mismatch repair (MMR) is the process which all organisms use to repair DNA damage. In evolutionary terms, MMR is a highly conserved process, which relies on the cooperation of numerous proteins to both identify and correct the various types of mismatches that can occur during replication, recombination and environmental induced damage. Given the above it might be expected that mutations in the genes encoding the proteins of the MMR system would have a significant effect on the efficiency of the repair process and this has been shown to be the case; For instance work in humans and Arabidopsis has shown that mutations in either MSH2 or PMS2 lead to deficiencies in MMR and to a corresponding increase in the frequency of mutations. In addition to their role in MMR MSH2, MSH3 and MSH6/7 have also been implicated in the suppression of recombination between non homologous sequences such as diverse alleles, paralogs and homoeologous chromosomes in allopolyploids. Such a suggestion correlates well with the reduced recombination rate seem between sequences showing even low levels of sequence diversity and the increased rate of recombination (in both somatic and meiotic tissue) between such sequences in Arabidopsis lines having reduced mismatch repair activity Via this proposal we intend to both characterise MSH2 and MSH6 wheat transgenes for evidence of reduced MMR and to examine if either they alone or in combination with existing transgenes for PMS2 show an additive effect and as such whether or not 'multiple' transgenes provide an even more efficient source of novel alleles. As proof of principle we then intend to examine the role of PMS2, MSH2 and MSH6 in allelic, paraologous and homoeologous recombination at the agricultural important Glu-1 loci which encodes the glutenin proteins. If our approach is successful we intend to use it to develop a strategy for increasing the rate of recombination occurring within the wheat genome.

Summary

Mismatch repair (MMR) is the process which all organisms use to repair DNA damage. We intend to generate wheat plants which have reduced levels of MMR and hence elevated levels of genetic diversity and recombination. As a proof of principle we intend to use this material to generate lines carrying novel combinations of HMW-glutenin alleles. Plants having greater allele diversity will be extremely valuable to wheat geneticists and wheat breeders as both a source of new alleles and as a means of recombining chromosomes to generate new variants. The approach builds upon our existing work using a truncated wheat Post Meiotic Segregation Increased 2 (TaPMS2) gene to reduce mismatch repair activity (MMR). In this proposal we intend to develop and characterise a series of transgenic lines carrying single and multiple gene constructs to further reduce MMR activity. We hypothesize that such plants will carry an increased level of allelic diversity, for instance within the glutenin loci, we also hypothesize that reduced MMR activity will lead to plants having a higher level of recombination between non-identical sequences. As such transgenic material might be problematical for today's wheat breeders, we also intend to pursue alternative, but longer term, routes to generate similar material via non-transgenic means.

Committee	Closed Committee - Agri-food (AF)
Research Topics	Crop Science, Plant Science
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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