Dissertation Research: Drivers of plant invasions: The role of fungi, nutrient availability and competition among plants

入侵物种是全球生物多样性丧失的主要驱动因素，每年要花费数十亿美元来控制。了解特定物种为何会成为入侵物种，对于开发有效的管理方法至关重要。在这方面，入侵植物与其相关真菌之间的相互作用可能特别重要。这些相互作用值得注意，因为真菌可以对植物产生积极和消极的影响；一些可能通过增加植物的竞争能力而使植物受益，而另一些可能通过引起疾病而损害植物。本研究将确定真菌的多样性和影响湿地草，芦苇（芦苇芦苇），有本地和入侵形式在北美。将进行实验，以确定真菌是否以不同的方式影响天然芦苇和入侵芦苇对不断变化的营养条件的反应。除了更好地了解真菌如何帮助传播一些入侵物种外，这项研究的结果还可能揭示真菌如何以新的方式来控制入侵物种的传播。此外，该项目将为研究生和本科生提供重要的研究训练。研究结果将通过科学会议、同行评议期刊上的出版物以及为儿童设计的关于入侵物种的海报进行分享，该海报将在路易斯安那州巴吞鲁日一个受欢迎的自然公园展出。虽然南稻的本土基因型在北美广泛分布，但欧洲基因型在过去150年中迅速传播。本文通过田间调查和温室试验，对南洋蓟入侵性的预测进行了验证：入侵南洋蓟基因型将具有1)叶片和土壤真菌多样性较低，2)叶片和土壤病原体的危害较小，3)与本地基因型相比，竞争能力和养分吸收能力更强。此外，还将进行试验，以确定养分有效性、土壤真菌和植物竞争是否以复杂的方式相互作用，以促进来自欧洲的南稻属基因型的入侵成功。将在整个北美进行叶面和土壤真菌的实地调查，以确保充分复制本地和入侵的南稻属基因型，并最大限度地提高遇到的真菌的多样性。叶面真菌将在实验室中从患病的叶片组织中培养，DNA测序将用于从培养物和土壤样本中识别真菌。植物-土壤反馈温室试验还将研究土壤生物、养分和竞争对南菖蒲本地和入侵基因型适应度的交互作用。

Invasive species are major drivers of biodiversity loss worldwide and cost billions of dollars each year to control. Understanding why particular species become invasive is critically important to developing effective methods for their management. In this regard, the interactions between invasive plants and their associated fungi may be particularly important. These interactions are noteworthy because fungi can have both positive and negative effects on plants; some may benefit plants by increasing their competitive ability and others may damage plants by causing disease. This study will determine the diversity and impacts of fungi on a wetland grass, common reed (Phragmites australis), that has both native and invasive forms in North America. Experiments will be conducted to determine whether fungi differently influence how native and invasive forms of common reed respond to changing nutrient conditions. In addition to providing a better understanding of how fungi may help spread some invasive species, results from this study may reveal how fungi can be used in novel ways to control the spread of invasive species. Furthermore, this project will provide important research training for graduate and undergraduate students. Research findings will be shared through scientific meetings, publications in peer-reviewed journals, and a poster on invasive species that is designed for children and displayed at a popular nature park in Baton Rouge, Louisiana.Although native genotypes of P. australis are widely distributed in North America, a European genotype has spread rapidly over the past 150 years. Using field surveys and a greenhouse experiment, the following predictions regarding the invasibility of P. australis will be tested: invasive P. australis genotypes will 1) have lower foliar and soil fungi diversity, 2) have less damage from foliar and soil pathogens, and 3) be superior in competitive and nutrient uptake ability in comparison to native genotypes. In addition, tests will be performed to determine if nutrient availability, soil fungi, and plant competition interact in complex ways to promote invasion success of P. australis genotypes from Europe. Field surveys of foliar and soil fungi will be conducted throughout North America, ensuring adequate replication of native and invasive P. australis genotypes and maximizing the diversity of fungi encountered. Foliar fungi will be cultured in the laboratory from diseased leaf tissue, and DNA sequencing will be used to identify fungi from cultures and soil samples. A plant-soil feedback greenhouse experiment will also be conducted to examine the interactive effects of soil biota, nutrients, and competition on the fitness of native and invasive genotypes of P. australis.