ABSTRACT In higher plants, male meiosis is a key process of microsporogenesis and is crucial for plant fertility. Male meiosis programs are prone to be influenced by altered temperature conditions. Studies have reported that an increased temperature (28°C) within a fertile threshold can affect the frequency of meiotic recombination in Arabidopsis. However, not much has been known how male meiosis responses to an extremely high temperature beyond the fertile threshold. To understand the impact of extremely high temperature on male meiosis in Arabidopsis, we treated flowering Arabidopsis plants with 36-38°C and found that the high-temperature condition significantly reduced pollen shed and plant fertility, and led to formation of pollen grains with varied sizes. The heat stress-induced unbalanced tetrads, polyad and meiotic restitution, suggesting that male meiosis was interfered. Fluorescence in situ hybridization (FISH) assay confirmed that both homologous chromosome separation and sister chromatids cohesion were influenced. Aniline blue staining of tetrad-stage pollen mother cells (PMCs) revealed that meiotic cytokinesis was severely disrupted by the heat stress. Supportively, immunolocalization of ɑ-tubulin showed that the construction of spindle and phragmoplast at both meiosis I and II were interfered. Overall, our findings demonstrate that an extremely high-temperature stress over the fertile threshold affects both chromosome segregation and cytokinesis during male meiosis by disturbing microtubular cytoskeleton in Arabidopsis.

中文翻译：

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热应激干扰拟南芥雄性减数分裂过程中的染色体分离和胞质分裂

摘要 在高等植物中，雄性减数分裂是小孢子发生的关键过程，对植物的生育能力至关重要。雄性减数分裂程序容易受到温度条件变化的影响。研究报告称，在可育阈值内升高的温度 (28°C) 会影响拟南芥中减数分裂重组的频率。然而，对于雄性减数分裂如何对超过生育阈值的极高温度做出反应知之甚少。为了解极高温对拟南芥雄性减数分裂的影响，我们对拟南芥开花植物进行了 36-38°C 处理，发现高温条件显着降低了花粉脱落和植株的生育力，并导致形成了不同程度的花粉粒。尺寸。热应激引起的不平衡四分体、多聚体和减数分裂恢复，表明雄性减数分裂受到干扰。荧光原位杂交 (FISH) 测定证实同源染色体分离和姐妹染色单体内聚都受到影响。四分体花粉母细胞（PMC）的苯胺蓝染色显示减数分裂胞质分裂被热应激严重破坏。支持性地，ɑ-微管蛋白的免疫定位表明在减数分裂I和II中纺锤体和成膜体的构建受到干扰。总体而言，我们的研究结果表明，超过可育阈值的极端高温胁迫通过扰乱拟南芥中的微管细胞骨架，影响雄性减数分裂过程中的染色体分离和胞质分裂。荧光原位杂交 (FISH) 测定证实同源染色体分离和姐妹染色单体内聚都受到影响。四分体花粉母细胞（PMC）的苯胺蓝染色显示减数分裂胞质分裂被热应激严重破坏。支持性地，ɑ-微管蛋白的免疫定位表明在减数分裂I和II中纺锤体和成膜体的构建受到干扰。总体而言，我们的研究结果表明，超过可育阈值的极端高温胁迫通过扰乱拟南芥中的微管细胞骨架，影响雄性减数分裂过程中的染色体分离和胞质分裂。荧光原位杂交 (FISH) 测定证实同源染色体分离和姐妹染色单体内聚都受到影响。四分体花粉母细胞（PMC）的苯胺蓝染色显示减数分裂胞质分裂被热应激严重破坏。支持性地，ɑ-微管蛋白的免疫定位表明在减数分裂I和II中纺锤体和成膜体的构建受到干扰。总体而言，我们的研究结果表明，超过可育阈值的极端高温胁迫通过扰乱拟南芥中的微管细胞骨架，影响雄性减数分裂过程中的染色体分离和胞质分裂。ɑ-微管蛋白的免疫定位表明减数分裂I和II中纺锤体和成膜体的构建受到干扰。总体而言，我们的研究结果表明，超过可育阈值的极端高温胁迫通过扰乱拟南芥中的微管细胞骨架，影响雄性减数分裂过程中的染色体分离和胞质分裂。ɑ-微管蛋白的免疫定位表明减数分裂I和II中纺锤体和成膜体的构建受到干扰。总体而言，我们的研究结果表明，超过可育阈值的极端高温胁迫通过扰乱拟南芥中的微管细胞骨架，影响雄性减数分裂过程中的染色体分离和胞质分裂。