DISSERTATION RESEARCH: Does hosting arbuscular mycorrhizal fungi in modular structures facilitate discrimination against cheaters?

大多数陆地植物依靠根部共生真菌(“菌根真菌”)来满足矿物质营养需求，并增强对病虫害的抵抗力。然而，许多快速生长的菌根真菌已经进化到利用它们的宿主，而没有提供任何这些服务，导致植物生长受阻，对环境胁迫的敏感性增加。印第安纳大学的布莱恩·斯泰丁格和詹姆斯·贝弗试图找出植物如何防御“作弊者”真菌。研究人员通过参与公共和少数族裔外联项目来增强他们的科学工作的影响。施泰丁格将通过詹姆斯·霍兰德夏季研究倡议(SRI)将科学界未被充分代表的少数群体纳入他在印第安纳大学的工作。SRI计划将高中生和大学一年级的学生都带到伊利诺伊州参加独立研究。施泰丁格将培训SRI学生如何测量菌根真菌并识别真菌作弊者，为他们提供在实验室环境中工作的实践经验。此外，斯坦丁格还将招募印第安纳大学的本科生协助研究的实验和数据分析部分，帮助他们培养可以应用于独立论文工作的技能。这项研究将加强该团队正在进行的研究，提供一种使用分子技术直接测试模型预测的方法，测量AMF对植物营养的影响，并扩大正在进行的实验，将Podocarps与不形成节根的植物进行比较。此外，研究人员还将在一项对新西兰罗汉果森林中AMF成分的比较研究中测试模型预测。为了实现这一点，他们创建了一个理论模型，该模型确定了寄主植物的特征，这些特征应该会增加它们在空间上隔离和终止对作弊菌株的资源投资的能力。其次，他们开发了一种有益真菌和欺骗真菌的实验系统，以确定不同植物宿主的防御效果。最后，他们从森林系统中收集根部，以确定他们实验系统中的防御系统是否对田野中的作弊真菌有效。Steidinger和Bever希望不仅发现植物如何防御具有剥削性的真菌，而且还希望阐明植物防御的共同特征，这些特征可能适用于各种互惠共生。

The majority of terrestrial plant species depend on symbiotic fungi that live inside their roots ("mycorrhizal fungi") to both meet their mineral nutrient demands and increase their defenses against pests and disease. However, many strains of fast-growing mycorrhizal fungi have evolved to exploit their hosts without providing any of these services, leaving plants with stunted growth and increased susceptibility to environmental stress. Brian Steidinger and James Bever of Indiana University (IU) seek to identify how plants can defend themselves against "cheater" fungi. The researchers enhance the impact of their scientific work through their involvement in public and minority outreach programs. Steidinger will integrate under-represented minorities in the sciences into his work at IU through the James Holland Summer Research Initiative (SRI). The SRI program brings both high school and freshmen college students to IU to participate in independent research. Steidinger will train SRI students how to measure mycorrhizal fungi and identify fungal cheaters, providing them with hands-on experience working in a lab setting. Further, Steidinger will recruit IU undergraduates to assist with the experimental and data analysis portions of the proposed research, helping them build skills they can apply towards independent thesis work. This research will enhance ongoing research by this team by providing a means to directly test model predictions using molecular techniques, measure the impact of AMF on plant nutrition, and expand an ongoing experiment to compare podocarps to plants that do not form nodulated roots. In addition, the researchers will test model predictions in a comparative study of AMF composition in a New Zealand podocarp forest. To achieve this, they created a theoretical model that identified features of a host plant that should increase their ability to spatially segregate and terminate resource investment into cheater strains. Second, they developed an experimental system of beneficial and cheater fungi to determine the effectiveness of defenses in different plant hosts. Finally, they collected roots from a forest system in order to determine if the defenses in their experimental system are effective against cheater fungi in the field. Steidinger and Bever hope to discover not only how plants defend themselves against exploitative fungi, but to shed light on common features of plant defenses that are likely to be applicable to a variety of mutualisms.