Altered tapetal PCD and pollen wall development in the Arabidopsis ms1 mutant
Altered tapetal PCD and pollen wall development in the Arabidopsis ms1 mutant
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DOI：
10.1093/jxb/erl032
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发表时间：
2006-08-01
影响因子：
6.9
通讯作者：
Wilson, Zoe A.
中科院分区：
文献类型：
--
作者：
Vizcay-Barrena, Gema;Wilson, Zoe A.
拟南芥雄性不育1突变导致成熟花药缺乏花粉。减数分裂和早期发育进展正常；然而，小孢子释放后，小孢子细胞质和绒毡层变得异常粒状和空泡化，发生变性。花粉壁发育受到严重影响；胼胝质壁内的初胺形成似乎正常发生，然而，一旦胼胝质降解，就会检测到电致密物质的异常沉积，导致不规则的穗状结构，而不是野生型杆状结构的特征。与野生型相比，内壁也减少了。TUNEL（末端脱氧核苷酸转移酶介导的dUTP缺口末端标记）染色和超微结构分析表明，野生型小孢子有丝分裂i后，绒毡层发生程序性细胞死亡（PCD）。然而，在ms1绒毡层中未见PCD的迹象，其中大的自噬空泡和线粒体肿胀表明，坏死性绒毡层的破坏发生在ms1突变体中，而不是正常的、受调节的PCD过程。在绒毡层中形成大的自噬液泡后，在突变的小孢子中检测到TUNEL染色，表明它们可能经历了基于pcd的分解，这是绒毡层畸变的继发性后果。根据这些观察，可以假设MS1的两种可能作用；MS1可能通过修饰与花粉壁发育有关的绒毡层特异性基因的转录，从而调节花粉壁物质的分泌，进而调控绒毡层的发育和绒毡层PCD。另外，MS1基因可能通过直接调节绒毡层的PCD和破裂来控制绒毡层的发育。
The Arabidopsis male sterility1 mutation results in mature anthers that are devoid of pollen. Meiosis and early development progress normally; however, after microspore release, the microspore cytoplasm and tapetum become abnormally granular and vacuolated, and degeneration occurs. Pollen wall development is seriously affected; primexine formation within the callose wall appears to occur normally, however, once the callose is degraded, abnormal deposits of electrodense material are detected which result in irregular spike-shaped structures, rather than the characteristic rod-like shape of the wild-type bacula. The internal intine wall is also reduced compared with wild type. TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling) staining and ultrastructural analysis have indicated that programmed cell death (PCD) occurs in the wild-type tapetum after microspore mitosis I. However, no signs of PCD are seen in the ms1 tapetum, where large autophagic vacuoles and mitochondrial swelling suggest that necrotic-based breakdown of the tapetum is occurring in the ms1 mutant rather than the normal, regulated PCD process. After the formation of the large, autophagic vacuole in the tapetum, TUNEL staining is detected in the mutant microspores, indicating that they may go through a PCD-based breakdown as a secondary consequence of the observed tapetal aberrations. Based on these observations, two possible roles for MS1 can be hypothesized; MS1 may function by modifying the transcription of tapetal-specific genes implicated in pollen wall development, which then regulate pollen wall material secretion and in turn wall development and tapetal PCD. Alternatively, the MS1 gene may control tapetal development by directly regulating tapetal PCD and breakdown.