湿地植物内生细菌多样性研究进展

Advance in Endophytic Bacterial Diversity of Wetland Plants

湿地植物内生细菌作为一种新型微生物资源,在维持湿地生态系统平衡中发挥重要作用。内生细菌系统分布于湿地植物的不同组织部位,具有丰富的物种多样性及污染物降解、非豆科固氮、促进植物生长和生物防治等功能。在湿地生态系统中,内生细菌在宿主植物体内受植物组织保护而免于外界恶劣环境干扰,更易发挥生物功能。综述了湿地植物内生细菌的概念、物种、分布和功能多样性,探讨了内生细菌在研究中存在的问题,并对其应用前景进行了展望。

Endophytic bacteria are a kind of microbe which colonize in the healthy plant tissue and establish harmonious union relations with plants. As a novel microbial resource, endophytic bacteria become an important part of the wetland ecosystem and play important roles in wetland water purification, ecosystem balance maintenance and stabilizing the growth and symbiotic relationship with wetland plants. Endophytic bacteria in wetland plants are rich of species diversity and widely distributed in different tissues including roots, stems,leaves, flowers and fruits of host plants, the number and species are differentially distributed depending on different host plants growing in different climate and nutrient conditions. A series metabolic activities of endophytic bacteria inside the host can inhibit the infection and propagation of host pathogen and pathogenic fungi,they can also indirectly promote the healthy growth of plants and increase the speed of pollutants degradation which is important for the protecting wetland plants diversity, strengthening purification ability of the wetlands as well as maintaining wetland ecological balance. In wetland ecosystems, only a small part of contaminants can be absorbed by plants while endophytic bacteria are the major part of wetland ecosystem as decomposers.Even under ultraviolet radiation, drying, changing temperature and other adverse external environment interference conditions, endophytic bacteria can also function in degrading pollutants because they are colonizing inside and being protected by plant tissues. Endophytic bacteria can form complex micro ecosystem and establish a dynamic balance with wetland plants to achieve a stable living space by colonization and rotating inside host plants. They can also promote host plant growth through biological nitrogen fixation, secretion of plant hormones, producing iron carrier and the synthesis of other substances or some other unknown ways. Meanwhile, they can also control plant diseases, insects and pests threating. Another function as being used as exogenous gene carrier is becoming popular in recent years. The reason for endophytic bacteria becoming a hot research topic at home and abroad is because of their development and extensive application value. Community structure, dynamics and biological mechanisms are the popular topics currently. With the further development and application of cultural and non-cultural methods, endophytic bacteria will also have broader application prospects in the field of ecological functionsof the wetlands. Traditional cultural method is the cornerstone of microbiological research and contributes to the development and utilization of microbial resources. However,non-cultural methods provide an effective mean for detecting bacterial population diversity and the relationship with the environment, broadening the framework and endophytic bacteria structures as well as categories ranges. However, methods of isolation and culture need to be further improved and domestic plant endophytic bacteria research is restricted to secondary metabolism, antibacterial activity and symbiotic mechanism with host plants. The impact of purification and symbiotic mechanism to the ecological balance of the wetland system is obviously lacking research and should be paid more attention to. This review summarizes the concept of endophytic bacteria, endophytic bacteria research methods, endophytic bacteria species and their distribution and functional diversity. Some discussions on endophytic bacteria research issues and their application prospects are also included.