The timely programmed cell death (PCD) of the tapetum, the innermost somatic anther cell layer in flowering plants, is critical for pollen development, including the deposition and patterning of the pollen wall. Although several genes involved in tapetal PCD and pollen wall development have been characterized, the underlying regulatory mechanism remains elusive. Here we report that PERSISTENT TAPETAL CELL2 (PTC2), which encodes an AT-hook nuclear localized protein in rice (Oryza sativa), is required for normal tapetal PCD and pollen wall development. The mutant ptc2 showed persistent tapetal cells and abnormal pollen wall patterning including absent nexine, collapsed bacula, and disordered tectum. The defective tapetal PCD phenotype of ptc2 was similar to that of a PCD delayed mutant, ptc1, in rice, while the abnormal pollen wall patterning resembled that of a pollen wall defective mutant, Transposable Element Silencing Via AT-Hook, in Arabidopsis (Arabidopsis thaliana). Levels of anther cutin monomers in ptc2 anthers were significantly reduced, as was expression of a series of lipid biosynthetic genes. PTC2 transcript and protein were shown to be present in the anther after meiosis, consistent with the observed phenotype. Based on these data, we propose a model explaining how PTC2 affects anther and pollen development. The characterization of PTC2 in tapetal PCD and pollen wall patterning expands our understanding of the regulatory network of male reproductive development in rice and will aid future breeding approaches.

中文翻译：

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正常的磁带程序性细胞死亡和花粉壁图案形成需要持久的胎盘细胞2。

绒毡层是开花植物中最里面的体细胞花药细胞层，绒毡层的及时程序性细胞死亡（PCD）对于花粉发育至关重要，包括花粉壁的沉积和形成图案。尽管已表征了绒毡层PCD和花粉壁发育的几个基因，但潜在的调控机制仍然难以捉摸。在这里我们报告说，正常的绒毡状PCD和花粉壁发育需要持久性TAPETAL CELL2（PTC2），它编码水稻（Oryza sativa）中的AT钩核定位蛋白。突变体ptc2表现出持续存在的绒毛膜细胞和异常的花粉壁图案，包括缺少内皮素，塌陷的小球和不规则的顶盖。水稻中ptc2的绒毛膜PCD表型与PCD延迟突变体ptc1相似。而异常的花粉壁模式类似于拟南芥（Arabidopsis thaliana）中的一个花粉壁缺陷突变体，即通过AT-Hook引起的转座元件沉默。ptc2花药中的花药角质单体水平显着降低，一系列脂质生物合成基因的表达也降低了。减数分裂后的花药中显示PTC2转录本和蛋白质，与观察到的表型一致。基于这些数据，我们提出一个模型，解释PTC2如何影响花药和花粉发育。在绒毡状PCD和花粉壁图案中对PTC2进行表征，扩大了我们对水稻雄性生殖发育调控网络的了解，并将有助于将来的育种方法。在拟南芥（Arabidopsis thaliana）中。ptc2花药中的花药角质单体水平显着降低，一系列脂质生物合成基因的表达也降低了。减数分裂后的花药中显示PTC2转录本和蛋白质，与观察到的表型一致。基于这些数据，我们提出一个模型，解释PTC2如何影响花药和花粉发育。在绒毡状PCD和花粉壁图案中对PTC2进行表征，扩大了我们对水稻雄性生殖发育调控网络的了解，并将有助于将来的育种方法。在拟南芥（Arabidopsis thaliana）中。ptc2花药中的花药角质单体水平显着降低，一系列脂质生物合成基因的表达也降低了。减数分裂后的花药中显示PTC2转录本和蛋白质，与观察到的表型一致。基于这些数据，我们提出一个模型，解释PTC2如何影响花药和花粉发育。在绒毡状PCD和花粉壁图案中对PTC2进行表征，扩大了我们对水稻雄性生殖发育调控网络的了解，并将有助于将来的育种方法。基于这些数据，我们提出一个模型，解释PTC2如何影响花药和花粉发育。在绒毡状PCD和花粉壁图案中对PTC2进行表征，扩大了我们对水稻雄性生殖发育调控网络的了解，并将有助于将来的育种方法。基于这些数据，我们提出一个模型，解释PTC2如何影响花药和花粉发育。在绒毡状PCD和花粉壁图案中对PTC2进行表征，扩大了我们对水稻雄性生殖发育调控网络的了解，并将有助于将来的育种方法。