Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent Ghent, Belgium.
Department of Plant Breeding and Genetics, Cornell University , Ithaca, NY, USA.
Front Plant Sci. 2014 Jun 17;5:279. doi: 10.3389/fpls.2014.00279. eCollection 2014.
Faithful chromosome segregation in meiosis is essential for ploidy stability over sexual life cycles. In plants, defective chromosome segregation caused by gene mutations or other factors leads to the formation of unbalanced or unreduced gametes creating aneuploid or polyploid progeny, respectively. Accurate segregation requires the coordinated execution of conserved processes occurring throughout the two meiotic cell divisions. Synapsis and recombination ensure the establishment of chiasmata that hold homologous chromosomes together allowing their correct segregation in the first meiotic division, which is also tightly regulated by cell-cycle dependent release of cohesin and monopolar attachment of sister kinetochores to microtubules. In meiosis II, bi-orientation of sister kinetochores and proper spindle orientation correctly segregate chromosomes in four haploid cells. Checkpoint mechanisms acting at kinetochores control the accuracy of kinetochore-microtubule attachment, thus ensuring the completion of segregation. Here we review the current knowledge on the processes taking place during chromosome segregation in plant meiosis, focusing on the characterization of the molecular factors involved.
在有性生命周期中，忠实的染色体分离对于倍性稳定性至关重要。在植物中，基因突变或其他因素导致的染色体分离缺陷会分别导致不平衡或非减数配子的形成，从而产生非整倍体或多倍体后代。准确的分离需要协调执行整个两个减数分裂细胞分裂过程中发生的保守过程。联会和重组确保了交叉的建立，交叉将同源染色体固定在一起，从而允许它们在第一次减数分裂中正确分离，这也受到细胞周期依赖性的有丝分裂黏连蛋白释放和姐妹动粒的单极附着到微管的严格调控。在减数分裂 II 中，姐妹动粒的双定向和适当的纺锤体定向正确地将染色体分离到四个单倍体细胞中。作用于动粒的检查点机制控制着动粒-微管附着的准确性，从而确保了分离的完成。本文综述了植物减数分裂中染色体分离过程中发生的过程的最新知识，重点介绍了所涉及的分子因素的特征。
