The post-pollination ethylene burst and the continuation of floral advertisement are harbingers of non-random mate selection in Nicotiana attenuata
The post-pollination ethylene burst and the continuation of floral advertisement are harbingers of non-random mate selection in Nicotiana attenuata
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DOI：
10.1111/j.1365-313x.2012.05011.x
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发表时间：
2012-08-01
期刊：
影响因子：
7.2
通讯作者：
Baldwin, Ian T.
中科院分区：
文献类型：
--
作者：
Bhattacharya, Samik;Baldwin, Ian T.
自交不亲和的烟草在火灾后生长在遗传多样性的种群中，开出的花可持续3天，并被各种授粉者访问。为了确定授粉后是否以及何时在自体和异体花粉之间发生非随机的交配选择，在对照的单一授粉和混合授粉中测定了种子父权和半活体花粉管生长。尽管所有的花粉来源在单一基因型授粉中都同样擅长结实种子，但在混合授粉中，无论母本基因型如何，自体花粉都是一致选择的。然而，在花冠开放后不久进行混合授粉时，在非自体花粉中出现了明显的配偶鉴别模式，包括在野生型花柱和转化花柱中对潮霉素B抗性(转化选择标记)的选择。然而，在不能产生(IrACO)或感知(ETR1)乙烯的植株中，花粉基因型之间的配偶选择完全停止。授粉后乙烯爆发主要来源于柱头和上部花柱，在两个母体生态型的8个供粉者的单一和混合人工授粉中，乙烯爆发与配偶选择密切相关。授粉后乙烯爆发还与苯丙酮的持续释放呈负相关，苯丙酮是最丰富的吸引授粉者的花冠衍生花的挥发性物质。我们认为，乙烯信号在交配选择中起着关键作用，授粉后乙烯爆发和苯丙酮释放的终止在定性和定量上都是预测合子前交配选择和种子亲缘关系的准确指标。
The self-compatible plant Nicotiana attenuata grows in genetically diverse populations after fires, and produces flowers that remain open for 3 days and are visited by assorted pollinators. To determine whether and when post-pollination non-random mate selection occurs among self and non-self pollen, seed paternity and semi-in vivo pollen tube growth were determined in controlled single/mixed pollinations. Despite all pollen sources being equally proficient in siring seeds in single-genotype pollinations, self pollen was consistently selected in mixed pollinations, irrespective of maternal genotype. However, clear patterns of mate discrimination occurred amongst non-self pollen when mixed pollinations were performed soon after corollas open, including selection against hygromycin B resistance (transformation selectable marker) in wild-type styles and for it in transformed styles. However, mate choice among pollen genotypes was completely shut down in plants transformed to be unable to produce (irACO) or perceive (ETR1) ethylene. The post-pollination ethylene burst, which originates primarily from the stigma and upper style, was strongly correlated with mate selection in single and mixed hand-pollinations using eight pollen donors in two maternal ecotypes. The post-pollination ethylene burst was also negatively correlated with the continuation of emission of benzylacetone, the most abundant pollinator-attracting corolla-derived floral volatile. We conclude that ethylene signaling plays a pivotal role in mate choice, and the post-pollination ethylene burst and the termination of benzylacetone release are accurate predictors, both qualitatively and quantitatively, of pre-zygotic mate selection and seed paternity.