2021년 한국식물생명공학회 국제학술발표회 및 총회

Abstract

Meiosis is critical to sexual reproduction and creates genetic diversity in most eukaryotes. During meiosis, homologous chromosomes pair and undergo reciprocal genetic exchange, called crossover. Crossovers have a profound effect on genetic diversity, and are a critical process during crop improvement, allowing new recombinant backgrounds to be generated. Meiotic crossover number is tightly restricted along chromosomes in most eukaryotes, despite an excess of initiating DNA double-strand breaks. The majority of plant crossovers are dependent on class I interfering repair pathway, with a minority formed via the class II pathway. Class II crossover is limited by anti-recombination pathways; however, similar pathways repressing class I crossovers have not been identified. We performed a forward genetic screen in Arabidopsis using fluorescent crossover reporters to identify high crossover rate (hcr) mutants. We identified HCR1, HCR2 and HCR3 as repressing class I crossovers. Genetic proof, cytological results, genome wide crossover mapping and high-throughput fluorescence reporter analyses revealed that HCR1 and HCR3 limit crossovers by controlling protein phosphorylation and interactions of pro-crossover factors in class I pathway, while HCR2 represses transcription of HEI10 encoding meiotic E3 ligase that promotes crossover number in a dosage dependent manner. Our findings shed light on new anti-recombination pathways by which class I interfering crossovers are restricted. I will present our genetic screen, advanced approaches and ongoing studies on meiotic crossover recombination in plants.