RT Journal Article SR Electronic T1 Two different pathways for initiation of Trichoderma reesei Rad51-only meiotic recombination JF bioRxiv FD Cold Spring Harbor Laboratory SP 644443 DO 10.1101/644443 A1 Li, Wan-Chen A1 Chuang, Yu-Chien A1 Chen, Chia-Ling A1 Timofejeva, Ljudmilla A1 Pong, Wen-Li A1 Chen, Yu-Jie A1 Wang, Chih-Li A1 Wang, Ting-Fang YR 2019 UL http://biorxiv.org/content/early/2019/05/20/644443.abstract AB Background Meiotic recombination is mainly, but not exclusively, initiated by Spo11-induced double strand breaks (DSBs) in some sexual eukaryotes. DSBs are repaired by one or two RecA-like recombinases (ubiquitous Rad51 and meiosis-specific Dmc1). In yeast and mammals, Dmc1 is superior to Rad51 in tolerating mismatched sequences during highly polymorphic hybrid meiosis. The mechanisms underlying Rad51-only meiotic recombination remain less studied.Results The Rad51-only filamentous fungus Trichoderma reesei has only one spo11 gene. Removal of spo11 from T. reesei genome does not affect normal sexual development, meiosis or chromosome synapsis, but results in decrease of interhomolog recombination products to 70%, crossover homeostasis and lower genetic interference. Our results also suggest that T. reesei Rad51, like yeast and mammalian Dmc1 (but not Rad51), can tolerate mismatched sequences during meiotic recombination. Moreover, Topoisomerase II might act redundantly (and predominantly) with Spo11 to initiate meiotic recombination.Conclusion We suggest that T. reesei is an emerging model for studying Spo11-independent and Rad51-only meiosis.