Unpredictability of nectar nicotine promotes outcrossing by hummingbirds in Nicotiana attenuata
Unpredictability of nectar nicotine promotes outcrossing by hummingbirds in Nicotiana attenuata
复制标题
DOI：
10.1111/j.1365-313x.2012.05008.x
复制
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：
Kessler, Danny;Bhattacharya, Samik;Baldwin, Ian T.
许多植物使用复杂的策略，以最大限度地提高他们的繁殖成功，通过异交。烟草花产生花蜜与尼古丁的浓度是排斥蜂鸟，增加花访问每株植物的数量。在选择测试使用本地蜂鸟，我们表明，这些重要的传粉者学会容忍高尼古丁花蜜，但更喜欢低尼古丁花蜜，并没有表现出尼古丁成瘾的迹象。花蜜尼古丁浓度，不像其他营养组织，是不可预测的变量之间的花，不仅在人群中，但也在人群中，甚至在一个花序内的花。为了评估花蜜尼古丁浓度的变化是否会增加异交，多态性微卫星标记，优化，以评估在本地N。envelopata种群中的植物进行异交，以比较沉默的生物合成基因的尼古丁生产（Napmt 1/2）的表达，并在对照空载体植物，这是花药切除和移植到本地种群。当只接触蜂鸟授粉时，花蜜中含有尼古丁的花朵产生的种子与不含尼古丁的花朵产生的种子相比，具有更多的遗传差异。随着花蜜烟碱水平在花序中的差异减少，N。在三种Dicer样（DCL）蛋白的各种组合中沉默的Attenuata植物中，小RNA可能参与植物内花蜜烟碱水平的不可预测的变化。
Many plants use sophisticated strategies to maximize their reproductive success via outcrossing. Nicotiana attenuata flowers produce nectar with nicotine at concentrations that are repellent to hummingbirds, increasing the number of flowers visited per plant. In choice tests using native hummingbirds, we show that these important pollinators learn to tolerate high-nicotine nectar but prefer low-nicotine nectar, and show no signs of nicotine addiction. Nectar nicotine concentrations, unlike those of other vegetative tissues, are unpredictably variable among flowers, not only among populations, but also within populations, and even among flowers within an inflorescence. To evaluate whether variations in nectar nicotine concentrations increase outcrossing, polymorphic microsatellite markers, optimized to evaluate paternity in native N. attenuata populations, were used to compare outcrossing in plants silenced for expression of a biosynthetic gene for nicotine production (Napmt1/2) and in control empty vector plants, which were antherectomized and transplanted into native populations. When only exposed to hummingbird pollinators, seeds produced by flowers with nicotine in their nectar had a greater number of genetically different sires, compared to seeds from nicotine-free flowers. As the variation in nectar nicotine levels among flowers in an inflorescence decreased in N. attenuata plants silenced in various combinations of three Dicer-like (DCL) proteins, small RNAs are probably involved in the unpredictable variation in nectar nicotine levels within a plant.