Some scientists believe that in nature, wolves prey on prey, which makes complex interactions between different biological populations, and is conducive to maintaining ecological balance. In fact, in the microbial community, there is such a phenomenon. Microbial predation involves protozoa, phages, bacteria and fungi with predation ability, etc.
Microbiologists found that there is a kind of myxobacteria in the microbial community, which has the characteristics of multicellular colony behavior. It is a kind of general predator predatory microbial group, and is considered as a high prokaryote. According to microbiologists, myxobacteria are like "wolves" in the microbial world. They are widely distributed in different environmental types such as soil / water. They can "prey" on living microbial cells (bacteria and fungi) or other biological macromolecules to obtain nutrition, and at the same time, they can respond to the external nutrition threshold to regulate the differentiation of nutrient cells into stress resistant myxospores (at the same time, they can also“ Intelligent "self-regulation according to the nutritional threshold of the external environment to better adapt to the external environment", so that the myxobacteria groups have good soil adaptability. Therefore, microbiologists speculate that myxobacteria are at the top of the food chain of soil microorganisms, and their predatory behavior may play an important role in the balance of soil microbial ecosystem.
This conjecture is confirmed by the research results of Professor Cui Zhongli, School of life sciences, Nanjing Agricultural University. Through the research on the interaction between myxobacteria, cucumber and soil microorganisms, the team found that, driven by rhizosphere secretion, myxobacteria EGb had a strong chemotaxis on maltose and maltitol, which made them migrate and colonize to the root, and regulated the soil microbial community structure through feeding during the migration process. It was also found that the relative abundance of predatory microorganisms in the soil of myxobacteria treatment group was significantly higher than that of other treatment groups, while the number of Fusarium oxysporum decreased significantly, thus inhibiting the occurrence of disease. The results reveal the temporal and spatial distribution of myxobacteria in the soil moving to the roots of plants, and propose and verify the hypothesis that the predatory behavior of myxobacteria drives the stability of beneficial microbial community structure of crops in the soil, so as to reduce the occurrence of diseases.
This study is the first to demonstrate the response of myxobacteria to rhizosphere exudates in the process of interaction between Myxobacteria and plants, to analyze the ecological function of myxobacteria predatory behavior, and to provide a new idea for biological control of plant pathogens. The relevant research results were published on the Journal Microbiology in the field of Microbiology under the title of "a preliminary myxotypium controls Cucumber Fusarium wilt by regulating the soil microbial community". The results have important guiding significance for understanding the interaction between predatory microorganisms, plants and soil microorganisms.
Ye Xianfeng, a postdoctoral student in the school of life sciences of Nanjing Agricultural University, and Dr. Li ZhouKun, a young teacher, are the co first authors, while Professor Cui Zhongli and Professor Zhang Ruifu are the co correspondents. Wang Hui, researcher of Nanjing Soil Research Institute, Chinese Academy of Sciences, fan Jiaqin, associate professor of Plant Protection College, Cao Hui, associate professor of Chinese Academy of Sciences and Huang Yan participated in the study. The project is supported by general programs of NSFC and major national basic research and development programs.
Source: Nanjing Agricultural University. Paper link:
https://doi.org/10.1186/s40168-020-00824-x