Pollen germinates precociously in the anthers of raring-to-go, an Arabidopsis gametophytic mutant
Pollen germinates precociously in the anthers of raring-to-go, an Arabidopsis gametophytic mutant
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DOI：
10.1104/pp.126.2.685
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发表时间：
2001-06-01
期刊：
影响因子：
7.4
通讯作者：
McCormick, S
中科院分区：
文献类型：
--
作者：
Johnson, SA;McCormick, S
花粉水合作用通常受到严格调节，只有当干燥的花粉粒从雌性那里获取水分时，花粉水合才会在体内发生，从而促进花粉管的生长。通过用脱色苯胺蓝（一种针对胼胝质的染色剂）染色，可以轻松观察到花粉管。我们发现了一种突变体，即“raring-to-go”，其中花粉粒在花药开裂前被胼胝质染色。当即将上市的植物转移到高湿度时，花药内的花粉管急剧伸长。早在双细胞阶段，即将上市的植物中受影响的花粉粒就在花药内获取或保留水分，并提前发芽。因此，避免了与女性接触的要求。我们使用花粉四分体分析表明，raring-to-go 是一种配子体突变，据我们所知，这是拟南芥中影响授粉途径早期事件的第一个配子体突变。为了帮助识别“raring-to-go”等位基因，我们设计了一种用脱色苯胺蓝批量筛选花粉的新技术。我们筛选了一个新的 M 诱变群体，并鉴定了几个具有“raring-to-go”表型的其他突变体，证明了该技术的有用性。此外，我们还分离出了具有意想不到的胼胝质染色模式的其他突变体（礼品包装花粉、圆点花粉和情感脆弱的花粉）。我们认为 raring-to-go 和这些其他突变体可能有助于剖析调节花粉水合和花粉管生长的途径的组成部分。
Pollen hydration is usually tightly regulated and occurs in vivo only when desiccated pollen grains acquire water from the female, thus enabling pollen tube growth. Pollen tubes are easily visualized by staining with decolorized aniline blue, a stain specific for callose. We identified a mutant, raring-to-go, in which pollen grains stained for callose before anther dehiscence. When raring-to-go plants are transferred to high humidity, pollen tubes dramatically elongate within the anther. As early as the bicellular stage, affected pollen grains in raring-to-go plants acquire or retain water within the anther, and precociously germinate. Thus, the requirement for contact with the female is circumvented. We used pollen tetrad analysis to show that raring-to-go is a gametophytic mutation, to our knowledge the first gametophytic mutation in Arabidopsis that affects early events in the pollination pathway. To aid in identifying raring-to-go alleles, we devised a new technique for screening pollen in bulk with decolorized aniline blue. We screened a new M, mutagenized population and identified several additional mutants with a raring-to-go-like phenotype, demonstrating the usefulness of this technique. Further, we isolated other mutants (gift- wrapped pollen, polka dot pollen, and emotionally fragile pollen) with unexpected patterns of callose staining. We suggest that raring-to-go and these other mutants may help dissect components of the pathway that regulates pollen hydration and pollen tube growth.