Epigenomic modification in rice controls meiotic recombination and segregation distortion

The low frequency of meiotic recombination in chromosomal regions other than hotspots is a general obstacle to efficient breeding. A number of active genes are present in recombination-repressed centromeric regions in higher eukaryotes, suggesting that suppression of meiotic recombination prevents shuffling of genes within a centromeric region. In this study, by using an inter-subspecific cross of Oryza sativa L., we show that modification of inactive chromatin states by either genetic or chemical inhibition of chromatin modifying proteins induced changes in both the position of meiotic recombination and, unexpectedly, the pattern of segregation distortion of parental alleles. Antisense knockdown of rice homologues of DECREASE IN DNA METHYLATION1 , which is required for the maintenance of heterochromatin in Arabidopsis thaliana , induced a recombination hotspot in a centromeric region accompanied by a steep increase in the proportion of heterozygotes. Our results describe a previously undocumented phenomenon in which artificial chromatin modification could be used to change the pattern of segregation distortion in rice and open up novel possibilities for efficient crop breeding.