Arabidopsis RPG1 is important for primexine deposition and functions redundantly with RPG2 for plant fertility at the late reproductive stage
Arabidopsis RPG1 is important for primexine deposition and functions redundantly with RPG2 for plant fertility at the late reproductive stage
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DOI：
10.1007/s00497-012-0208-1
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发表时间：
2013-06-01
影响因子：
3.4
通讯作者：
Yang, Zhong-Nan
中科院分区：
文献类型：
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作者：
Sun, Ming-Xi;Huang, Xue-Yong;Yang, Zhong-Nan
拟南芥破裂花粉粒-1（RPG 1/Sweet 8）是MtN 3/唾液蛋白家族的成员，其功能是糖转运蛋白。rpg 1突变体显示有缺陷的外壁图案形成。在这项研究中，透射电子显微镜（TEM）观察表明，少得多的primexine沉积在rpg 1四分体。此外，小孢子膜波动异常，孢粉素积累也有缺陷。这表明，减少primexine沉积在rpg 1导致异常的膜波动，影响外壁图案的形成。化学染色显示rpg 1胼胝质壁变薄，以及胼胝质合成酶-5（CalS 5）在rpg 1中的表达显著降低。Rpg 1突变体的生育能力可以部分恢复在后期生殖阶段，可能补充部分由RPG 2，MtN 3/唾液家族的另一个成员，这是在花药中表达的小孢子发生。双突变体，rpg 1 rpg 2，几乎是不育的，并没有恢复在后期繁殖。这些结果表明，RPG 1和RPG 2参与primexine沉积，因此花粉壁图案的形成。
Arabidopsis Ruptured Pollen Grain-1 (RPG1/Sweet8) is a member of the MtN3/saliva protein family that functions as a sugar transporter. The rpg1 mutant shows defective exine pattern formation. In this study, transmission electron microscopy (TEM) observations showed that much less primexine was deposited in rpg1 tetrads. Furthermore, microspore membrane undulation was abnormal, and sporopollenin accumulation was also defective. This suggests that a reduced primexine deposition in rpg1 leads to abnormal membrane undulation that affects exine pattern formation. Chemical staining revealed thinning of the callose wall of rpg1, as well as significantly reduced expression of Callose synthase-5 (CalS5) in rpg1. The fertility of the rpg1 mutant could be partly restored at late reproductive stages, potentially complemented in part by RPG2, another member of the MtN3/saliva family, which is expressed in the anther during microsporogenesis. The double mutant, rpg1rpg2, was almost sterile and was not restored during late reproduction. These results suggest that RPG1 and RPG2 are involved in primexine deposition and therefore pollen wall pattern formation.