Ballhausen Max-Bernhard, van Veen Johannes A, Hundscheid Maria P J, de Boer Wietse
Department of Microbial Ecology, Netherlands Institute of EcologyWageningen, Netherlands; Department of Plant Health, Institute for Vegetable and Ornamental CropsGroßbeeren, Germany.
Department of Microbial Ecology, Netherlands Institute of EcologyWageningen, Netherlands; Institute of Biology Leiden, Leiden UniversityLeiden, Netherlands.
Front Microbiol. 2015 Dec 22;6:1416. doi: 10.3389/fmicb.2015.01416. eCollection 2015.
Mycophagous soil bacteria are able to obtain nutrients from living fungal hyphae. However, with exception of the soil bacterial genus Collimonas, occurrence of this feeding strategy has not been well examined. Evaluation of the importance of mycophagy in soil bacterial communities requires targeted isolation methods. In this study, we compared two different approaches to obtain mycophagous bacteria from rhizospheric soil. A short-term method based on baiting for bacteria that can rapidly adhere to fungal hyphae and a long-term method based on the enrichment of bacteria on fungal hyphae via repeated transfer. Hyphae-adhering bacteria were isolated, identified by 16S rDNA sequencing and tested for antifungal activity and the ability to feed on fungi as the sole source of carbon. Both methods yielded a range of potentially mycophagous bacterial isolates with little phylogenetic overlap. We also found indications for feeding preferences among the potentially mycophagous bacteria. Our results indicate that mycophagy could be an important growth strategy for rhizosphere bacteria. To our surprise, we found several potential plant pathogenic bacteria among the mycophagous isolates. We discuss the possible benefits that these bacteria might gain from colonizing fungal hyphae.
食真菌土壤细菌能够从活的真菌菌丝中获取营养。然而，除了土壤细菌属Collimonas外，这种取食策略的发生情况尚未得到充分研究。评估真菌食性在土壤细菌群落中的重要性需要有针对性的分离方法。在本研究中，我们比较了两种从根际土壤中获取食真菌细菌的不同方法。一种基于诱饵法的短期方法，用于捕获能快速附着在真菌菌丝上的细菌；另一种基于通过反复转移在真菌菌丝上富集细菌的长期方法。分离出附着在菌丝上的细菌，通过16S rDNA测序进行鉴定，并测试其抗真菌活性以及以真菌作为唯一碳源的取食能力。两种方法都产生了一系列潜在的食真菌细菌分离株，它们的系统发育重叠很少。我们还发现了潜在食真菌细菌之间存在取食偏好的迹象。我们的结果表明，真菌食性可能是根际细菌的一种重要生长策略。令人惊讶的是，我们在食真菌分离株中发现了几种潜在的植物病原菌。我们讨论了这些细菌从定殖于真菌菌丝中可能获得的潜在益处。
