Xingwang Li
Junkai Zhu
Xiaobin Liu
Zhenghu Chu
Jiali Shen
Changyin Wu
a National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China;
b Jiangsu Kingearth Seed Co., Ltd., Yangzhou 225012, China
Funds: We thank Prof. Jiankang Zhu for providing the CRISPR-Cas9 single target system. We thank Prof. Yaoguang Liu for providing the CRISPR-Cas9 multi-target system. We thank Prof. Wanqi Liang for providing the antibody against REC8. This work was supported by the National Natural Science Foundation of China (31630054, 31425018, 31821005) and Program for Chinese Outstanding Talents in Agricultural Scientific Research.
Received Date: 2021-04-15
Accepted Date:2021-04-27
Rev Recd Date:2021-04-25
Publish Date:2021-06-20
Abstract
Abstract
Meiotic recombination is essential for reciprocal exchange of genetic information between homologous chromosomes and their subsequent proper segregation in sexually reproducing organisms. MLH1 and MLH3 belong to meiosis-specific members of the MutL-homolog family, which are required for normal level of crossovers (COs) in some eukaryotes. However, their functions in plants need to be further elucidated. Here, we report the identification of OsMLH1 and reveal its functions during meiosis in rice. Using CRISPR-Cas9 approach, two independent mutants, Osmlh1-1 and Osmlh1-2, are generated and exhibited significantly reduced male fertility. In Osmlh1-1, the clearance of PAIR2 is delayed and partial ZEP1 proteins are not loaded into the chromosomes, which might be due to the deficient in resolution of interlocks at late zygotene. Thus, OsMLH1 is required for the assembly of synapsis complex. In Osmlh1-1, CO number is dropped by ~53% and the distribution of residual COs is consistent with predicted Poisson distribution, indicating that OsMLH1 is essential for the formation of interference-sensitive COs (class I COs). OsMLH1 interacts with OsMLH3 through their C-terminal domains. Mutation in OsMLH3 also affects the pollen fertility. Thus, our experiments reveal that the conserved heterodimer MutLγ (OsMLH1-OsMLH3) is essential for the formation of class I COs in rice.Keywords: Meiosis,
Crossover,
OsMLH1,
OsMLH3,
Rice
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