Dimensions: Testing the Potential of Pathogenic Fungi to Control the Diversity, Distribution, and Abundance of Tree Species in a Neotropical Forest Community

该项目将在观察和实验的组合中整合分类学、遗传学和功能方法，以测试热带树木多样性和稀有性的敌人易感性假说(ESH)。这一假说预测，稀有树种将比普通树种拥有更多的中空树干，拥有更多的致病真菌物种，并且与其他树种分享更多的这些病原体。在巴拿马巴罗科罗拉多岛的森林地块上，研究人员将调查所有树木，采样和培养真菌，并确定哪些树木上存在哪些真菌物种。将测试真菌的致病性和特异性，并将通过比较基因组序列分析来探索为什么一些真菌物种比其他物种具有更广泛的寄主范围的机制基础。如果敌人易感性假说经得起这些测试，它可能会被证明是对世界各地热带森林树种高度多样性和稀有性的一般解释。该项目还将包括高中生和大学生，以及来自加利福尼亚州、佐治亚州和巴拿马的高中理科教师。参与者将前往巴拿马，参加为期两周的野外生物学课程，这将使他们接触到目前可用的高通量DNA测序技术正在开放进行研究的令人兴奋的生态学和进化方面的新研究问题。这门课程将在项目的前三年每年教授。

The project will integrate taxonomic, genetic, and functional approaches in a combination of observations and experiments to test the Enemy Susceptibility Hypothesis (ESH) for tropical tree diversity and rarity. This hypothesis predicts that rare tree species will have a greater percentage of hollow-trunk trees, harbor more pathogenic fungal species, and also share more of these pathogens with other tree species, than common tree species. At forest plots on Barro Colorado Island, Panama, researchers will survey all trees, sample and culture fungi, and determine which fungal species are present on which trees. Fungal pathogenicity and specificity will be tested, and the mechanistic basis for why some fungal species have broader host ranges than others will be explored through comparative genomic sequence analyses. If the Enemy Susceptibility Hypothesis holds up to these tests, it may prove to be a general explanation for the high diversity and rarity of tree species in tropical forests worldwide. The project will also include participation of high school and college students, as well as high school science teachers from California, Georgia, and Panama. The participants will travel to Panama and take a two-week field-biology course that will expose them to the exciting new research questions in ecology and evolution being opened for study by the high-throughput DNA sequencing technologies now available. This course will be taught each year for the first three years of the project.