Component of a topoisomerase 6 complex specifically required for meiotic recombination (PubMed:26917763, PubMed:28855712). Together with SPO11 (SPO11-1 and SPO11-2), mediates DNA cleavage that forms the double-strand breaks (DSB) that initiate meiotic recombination (PubMed:26917763, PubMed:28855712). The complex promotes relaxation of negative and positive supercoiled DNA and DNA decatenation through cleavage and ligation cycles (PubMed:26917763). Heterotetramer of 2 SPO11 (SPO11-1 and/or SPO11-2) and 2 MTOPVIB chains (Probable). Interacts with SPO11-1 and SPO11-2 (PubMed:26917763, PubMed:28855712). Binds to PRD1 (PubMed:28855712). Localizes to meiotic chromosomes from leptotene to pachytene (PubMed:26917763). Mostly present in the nucleus, but also present in the cytoplasm (PubMed:28855712). Expressed ubiquitously in different tissues, including roots, stems, leaves, seedlings, inflorescences, siliques and pollen grains, specially as a higher level in inflorescence. Despite a weak sequence similarity, retains most of the structural features of the ancestral archaeal Top6B subunit (AC O05207), including the transducer domain that interacts with the SPO11 subunit and the ATP-binding fold, also named GHKL fold. Defective in meiosis (PubMed:28855712). Sterility due to male and female gamete developmental defects leading to disturbed embryo sac development and abnormal pollen formation (PubMed:26917763, PubMed:28855712). Strong reduction in bivalent formation at metaphase I caused by defects in meiotic double-strand breaks (DSB) formation (PubMed:26917763, PubMed:28855712). Impaired homologous chromosome synapsis and recombination (PubMed:28855712). Belongs to the TOP6B-like family.