Pollination induces mRNA poly(A) tail-shortening and cell deterioration in flower transmitting tissue.
Pollination induces mRNA poly(A) tail-shortening and cell deterioration in flower transmitting tissue.
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DOI：
10.1046/j.1365-313x.1996.9050715.x
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发表时间：
1996-05
期刊：
影响因子：
--
通讯作者：
Hong Wang;Hen-Ming Wu;A. Cheung
中科院分区：
文献类型：
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作者：
Hong Wang;Hen-Ming Wu;A. Cheung
花粉在花中引起许多生理反应，包括特定雌蕊细胞类型的退化和死亡。结果表明，在烟草花柱内，授粉引起的细胞退化仅限于传递组织，而周围的皮层组织不受影响。它不同于一般的衰老，因为外源的衰老诱导激素乙烯，或其前体氨基环丙烷-1-羧酸（ACC），花或雌蕊诱导整个花的整体恶化。此外，花粉管生长和乙烯的作用是需要整个频谱的细胞变化与此授粉诱导的传递组织退化过程。它还表明，授粉诱导的mRNA聚（A）尾缩短至少三个主要类别的传输组织特异性mRNA。正如通常观察到的poly（A）尾缩短的mRNA，这三种mRNA中的两种在授粉后水平下降。另一方面，第三类mRNA，传输组织特异性（TTS）的mRNA，保持在一个非常高的水平，授粉后，即使在大量的聚（A）尾缩短。TTS基因编码的花粉管生长促进和吸引蛋白需要在体内最佳的花粉管生长。TTS mRNA在退化的传递组织细胞中的特异性保存表明，这些细胞可以区分授粉花柱所需的分子和那些被破坏的分子，并保护它们免受降解。授粉诱导的mRNA poly（A）尾缩短和细胞死亡是适应授粉后传递组织环境的程序化过程。结果表明，ACC是一个候选的信号分子授粉诱导的mRNA缩短，这是加重乙烯和介导的蛋白磷酸化依赖的信号转导途径。
Pollination induces many physiological responses in the flower, including deterioration and death in specific pistil cell types. It is shown here that within the style of tobacco, pollination-induced cell deterioration was restricted to the transmitting tissue while the surrounding cortical tissue was not affected. It was distinct from general senescence since exogenously applying the senescence-inducing hormone ethylene, or its precursor aminocyclopropane-1-carboxylic acid (ACC), to the flower or the pistil induced overall deterioration in the entire flower. Furthermore, both pollen tube growth and ethylene action were needed for the entire spectrum of cellular changes associated with this pollination-induced transmitting tissue deterioration process. It is also shown that pollination-induced mRNA poly(A) tail-shortening for at least three major classes of transmitting tissue-specific mRNAs. As is commonly observed for poly(A) tail-shortened mRNAs, the levels of two of these three mRNA classes decline after pollination. On the other hand, the third class of mRNAs, transmitting tissue-specific (TTS) mRNAs, was maintained at a very high level subsequent to pollination, even after substantial poly(A)-tail shortening. TTS mRNAs encode a pollen tube growth-promoting and -attracting protein needed for optimal in vivo pollen tube growth. The specific preservation of TTS mRNAs in the deteriorating transmitting tissue cells suggests that these cells can distinguish molecules needed in the pollinated styles from those that are dispensable, and protect them from degradation. It is suggested that the pollination-induced mRNA poly(A) tail-shortening and cell death are programmed processes suited to the post-pollination transmitting tissue environment. Results showing that ACC is a candidate signal molecule for the pollination-induced mRNA-shortening which is accentuated by ethylene and mediated via a protein phosphorylation-dependent signal transduction pathway are also presented.