Departamento de Genética, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, 13418-900, Piracicaba, São Paulo, Brazil.
Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, SP, 13635-900, Pirassununga, São Paulo, Brazil.
Plant J. 2024 Jun;118(6):2094-2107. doi: 10.1111/tpj.16731. Epub 2024 Mar 25.
The sugarcane (Saccharum spp.) genome is one of the most complex of all. Modern varieties are highly polyploid and aneuploid as a result of hybridization between Saccharum officinarum and S. spontaneum. Little research has been done on meiotic control in polyploid species, with the exception of the wheat Ph1 locus harboring the ZIP4 gene (TaZIP4-B2) which promotes pairing between homologous chromosomes while suppressing crossover between homeologs. In sugarcane, despite its interspecific origin, bivalent association is favored, and multivalents, if any, are resolved at the end of prophase I. Thus, our aim herein was to investigate the purported genetic control of meiosis in the parental species and in sugarcane itself. We investigated the ZIP4 gene and immunolocalized meiotic proteins, namely synaptonemal complex proteins Zyp1 and Asy1. The sugarcane ZIP4 gene is located on chromosome 2 and expressed more abundantly in flowers, a similar profile to that found for TaZIP4-B2. ZIP4 expression is higher in S. spontaneum a neoautopolyploid, with lower expression in S. officinarum, a stable octoploid species. The sugarcane Zip4 protein contains a TPR domain, essential for scaffolding. Its 3D structure was also predicted, and it was found to be very similar to that of TaZIP4-B2, reflecting their functional relatedness. Immunolocalization of the Asy1 and Zyp1 proteins revealed that S. officinarum completes synapsis. However, in S. spontaneum and SP80-3280 (a modern variety), no nuclei with complete synapsis were observed. Importantly, our results have implications for sugarcane cytogenetics, genetic mapping, and genomics.
甘蔗（Saccharum spp.）基因组是所有基因组中最复杂的之一。现代品种是高度多倍体和非整倍体，这是由于甘蔗属间杂种 S. officinarum 和 S. spontaneum 杂交的结果。除了小麦 Ph1 座位上含有 ZIP4 基因（TaZIP4-B2）的研究外，多倍体物种的减数分裂控制研究很少，该基因促进同源染色体的配对，同时抑制同系物之间的交叉。在甘蔗中，尽管其具有种间起源，但二价体联会是有利的，如果有任何多价体，它们都会在前期 I 结束时解决。因此，我们旨在研究亲本物种和甘蔗本身减数分裂的假定遗传控制。我们研究了 ZIP4 基因和减数分裂蛋白，即联会复合体蛋白 Zyp1 和 Asy1。甘蔗 ZIP4 基因位于染色体 2 上，在花中表达更为丰富，与 TaZIP4-B2 发现的模式相似。在新的同源多倍体 S. spontaneum 中，ZIP4 表达更高，而在稳定的八倍体物种 S. officinarum 中表达较低。甘蔗 Zip4 蛋白含有一个 TPR 结构域，对于支架至关重要。还预测了其 3D 结构，发现与 TaZIP4-B2 非常相似，反映了它们的功能相关性。Asy1 和 Zyp1 蛋白的免疫定位显示，S. officinarum 完成了联会。然而，在 S. spontaneum 和 SP80-3280（一种现代品种）中，没有观察到具有完整联会的核。重要的是，我们的结果对甘蔗细胞遗传学、遗传图谱和基因组学具有重要意义。
