Involved in meiotic recombination. Required for reciprocal recombination and proper segregation of homologous chromosomes at meiosis. Promotes homologous recombination through facilitating chiasma formation during prophase I. Involved in the control of class I crossover (interference-sensitive crossover) formation. Detected in punctuate foci onto the chromosomes during the early meiotic prophase I. Highly expressed in the panicles. Normal vegetative growth but severe reduction in fertility due to a decrease in chiasma frequency at metaphase I of meiosis. Belongs to the DNA mismatch repair MutS family.