Research Starter Grant: Investigating the impacts of loline catabolizing bacteria on fitness of their tall fescue host

骆林生物碱是由内生真菌Neotyphodium sp.作为共生关系的一部分，以防止昆虫食草动物消耗他们的高羊茅宿主。以前的研究表明，一些高羊茅的附生细菌定植可以利用这些生物碱作为唯一的碳源。这种细菌在含碱液的草上比其他菌株生长得更大。人们认为，在草层球上，碱分解细菌、寄主和内生真菌之间存在着多营养共生关系。本项目将测试碱分解细菌附生菌对寄主生长的潜在积极影响。这些细菌将通过生长试验、显微镜和生物化学来筛选植物生长调节剂、生长素和细胞分裂素的生产。此外，还将通过筛选氯碱分解菌对寄主草的保护作用进行研究。细菌通过生态位排斥来保护宿主的能力也将被检验。这些测试将结合培养和生物化学技术。最后，研究了利用碱分解菌株对含草新伤寒菌的亲和力对主要污染物阿特拉津进行生物修复的潜力。从这项工作中收集的数据将对当前有关微生物相互作用的科学知识产生广泛的影响。这项工作可能会产生一种从环境中去除阿特拉津的有效方法，这将为子孙后代产生更安全的地下水。

Loline alkaloids are made by the endophytic fungus Neotyphodium sp. as part of a symbiotic relationship to keep insect herbivores from consuming their tall fescue host. Previous research has indicated that some epiphytic bacterial colonizers of tall fescue can use these alkaloids as a sole carbon source. Such bacteria grow to higher population sizes on loline containing grasses than other bacterial strains. It is thought that a multi-trophic symbiosis is occurring on the grass phyllosphere between the loline catabolizing bacteria, the host, and the endophytic fungus. This project will test the potential positive impact of loline catabolizing bacterial epiphytes on growth of the host. The bacteria will be screened for production of the plant growth regulators, auxin and cytokinin, through growth assays, microscopy, and biochemistry. Additionally, the protective impacts of loline catabolizing bacteria on the host grasses will be investigated by screening them for the antimicrobial production. The ability of the bacteria to protect their hosts via niche exclusion will also be examined. A combination of culturing and biochemistry techniques will be conducted for these tests. Finally, the potential to take advantage of the affinity of loline catabolizing strains to Neotyphodium sp. harboring grasses for the bioremediation of the major pollutant Atrazine will be tested. The data collected from this work will have broad implications on the current scientific knowledge concerning microbe:microbe interactions. Potentially, this work may result in an efficient way to remove atrazine from the environment, which would generate safer ground water for future generations.