ATP-Binding Cassette Transporter G26 Is Required for Male Fertility and Pollen Exine Formation in Arabidopsis
ATP-Binding Cassette Transporter G26 Is Required for Male Fertility and Pollen Exine Formation in Arabidopsis
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DOI：
10.1104/pp.110.161968
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发表时间：
2010-10-01
期刊：
影响因子：
7.4
通讯作者：
Douglas, Carl J.
中科院分区：
文献类型：
--
作者：
Quilichini, Teagen D.;Friedmann, Michael C.;Douglas, Carl J.
高抗性生物聚合物，孢粉素，赋予孢子和花粉粒的外壁（外壁）无与伦比的强度，保护这些结构免受陆地应力的影响。尽管对孢粉素的组成了解有限，但似乎孢粉素的合成发生在绒毡层中，并且需要将一种或多种孢粉素成分运输到发育中的小孢子表面。在这里，我们描述ABCG 26，ATP结合盒（ABC）转运蛋白超家族的成员，这是所需的花粉外壁形成在拟南芥（拟南芥）。ABCG 26突变体的育性严重降低，大多数角果不能通过自花受精产生种子，成熟花药不能释放花粉。透射电子显微镜分析显示，缺乏外壁上的abcg 26 -1突变体小孢子。花粉壁形成的表型异常首先出现在早期单核小孢子中，表现为缺乏外壁形成和孢粉素沉积。此外，ABCG 26 mRNA的最高水平是在绒毡层，在早期花粉壁形成，孢粉素生物合成，和孢粉素沉积。积累类似于三层螺旋状线圈在abcg 11和abcg 12突变体缺陷角质层蜡出口观察在花药室的abcg 26突变体。一个黄色的荧光蛋白ABCG 26蛋白定位于内质网和质膜。我们的研究结果表明，ABCG 26在外壁形成和花粉发育中起着至关重要的作用，并且与ABCG 26将孢粉素前体穿过绒毡层质膜运输到室中用于在发育中的小孢子壁上聚合的模型一致。
The highly resistant biopolymer, sporopollenin, gives the outer wall (exine) of spores and pollen grains their unparalleled strength, shielding these structures from terrestrial stresses. Despite a limited understanding of the composition of sporopollenin, it appears that the synthesis of sporopollenin occurs in the tapetum and requires the transport of one or more sporopollenin constituents to the surface of developing microspores. Here, we describe ABCG26, a member of the ATP-binding cassette (ABC) transporter superfamily, which is required for pollen exine formation in Arabidopsis (Arabidopsis thaliana). abcg26 mutants are severely reduced in fertility, with most siliques failing to produce seeds by self-fertilization and mature anthers failing to release pollen. Transmission electron microscopy analyses revealed an absence of an exine wall on abcg26-1 mutant microspores. Phenotypic abnormalities in pollen wall formation were first apparent in early uninucleate microspores as a lack of exine formation and sporopollenin deposition. Additionally, the highest levels of ABCG26 mRNA were in the tapetum, during early pollen wall formation, sporopollenin biosynthesis, and sporopollenin deposition. Accumulations resembling the trilamellar lipidic coils in the abcg11 and abcg12 mutants defective in cuticular wax export were observed in the anther locules of abcg26 mutants. A yellow fluorescent protein-ABCG26 protein was localized to the endoplasmic reticulum and plasma membrane. Our results show that ABCG26 plays a critical role in exine formation and pollen development and are consistent with a model by which ABCG26 transports sporopollenin precursors across the tapetum plasma membrane into the locule for polymerization on developing microspore walls.