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Abstract

A greater understanding of the control of recombination in crop plants would be particularly useful for crop species such as barley (and wheat) where a highly skewed distribution of meiotic crossover events means that up to half of the genes rarely, if ever, recombine.  In these crops, substantial proportions of the chromosomes are inherited together as a large linkage block, preventing the generation of novel gene combinations and useful variation that could be exploited in breeding programmes. In order to improve our understanding of recombination in barley, and ultimately to be able to modulate recombination in barley, we are characterizing a collection of 14 non-allelic desynaptic (des) mutants that exhibit perturbed meiosis and semi-sterility compared to wild type. A number of these mutants have now been genetically mapped using the semi-sterility phenotype and cytologically characterized. In particular, 3D-SIM microscopy analysis reveals that each mutant is differently affected for synapsis, crossing over formation and meiosis progression. We will discuss results of some of these mutants, showing the importance of the interplay between synapsis and recombination and the implication for the modulation of recombination for breeding purpose.

References:

• Isabelle Colas, Benoit Darrier, Mikel Arrieta, Sybille Mittmann, Luke Ramsay, Pierre Sourdille and Robbie Waugh. Observation of extensive chromosome axis remodelling during the ‘diffuse-phase’ of meiosis in large genome cereals. (2017) Frontiers in Plant Sciences. Jul 13;8:1235.
• Isabelle Colas, Malcolm Macaulay, James D. Higgins, Dylan Phillips, Abdellah Barakate, Markus Posch, Sue J. Armstrong, F. Chris H. Franklin, Claire Halpin, Robbie Waugh, and Luke Ramsay. A spontaneous mutation in MutL-Homolog 3 (HvMLH3) affects synapsis progression and crossover resolution in the barley desynaptic mutant des10. (2016) New Phytol. 212(3):693-707
• Barakate A, Higgins JD, Vivera S, Stephens J, Perry RM, Ramsay L, Colas I, Oakey H, Waugh R, Franklin FC, Armstrong SJ, Halpin C. The synaptonemal complex protein ZYP1 is required for imposition of meiotic crossovers in barley. (2014) Plant Cell. Feb;26(2):729-40.