Immigrant Amplification and Population Dynamics of Fungi on Leaf Islands

生长在叶片内或叶片上的微生物在与叶片相关的生命周期阶段、大气中的运输阶段和在相同或不同植物物种的另一片叶片上生长之间交替生长。这个项目试图通过数学模型和实验测试来解释，通过相对较少数量的迁徙微生物细胞涌入树叶，如何协同提高常驻微生物种群。这些模型将通过检查苹果叶片表面自然和实验增强的酵母状真菌--出芽短梗霉的水平来进行测试。现场测试将通过使用分子标记方法来促进，该方法允许区分出芽短梗霉的背景种群和引入的移民种群。该项目具有两个重要的科学意义。首先，它可能有助于解释当迁徙的数量相对于现有种群的规模很小时，物种种群是如何在孤立的斑块中生存和竞争的。其次，寄生在树叶上的微生物会引起重要的植物疾病。这些病原体具有出芽孢杆菌的许多特征。因此，这一系统应该对微生物植物疾病的生物学和流行病学有更大的量化洞察力。

Microorganisms that grow within or upon leaves alternate between a life cycle phase associated with the leaf, a transport phase in the atmosphere, and growth on another leaf of the same or different plant species. This project seeks to explain, both by mathematical models and experimental tests, how a resident population of microbes can be elevated synergistically by the influx of relatively small numbers of immigrant microbe cells to the leaf. The models will be tested by examination of natural and experimentally enhanced levels of a yeast- like fungus, Aureobasidium pullulans, on apple leaf surfaces. The field tests will be facilitated by use of molecular marker methods, which allow the background population of A. pullulans to be discriminated from the introduced immigrant population.This project has two significant scientific implications. First, it may help explain how populations of species survive and compete in nature in isolated patches when the number of immigrants is small relative to the size of the extant population. Second, microbes inhabiting leaves cause important plant diseases. These pathogens share many of the features of A. pullulans. Therefore, this system should give greater quantitative insight into the biology and epidemiology of microbial plant diseases.