由我们根瘤菌研究中心人员参与写作和编著的根瘤菌专著《Ecology and Evolution of Rhizobia: Principles and Applications》，于2019年年底由Springer公司出版了。这本书总结了我们国家及世界上对根瘤菌分类学、系统学、进化学、基因组学、地理学、共生互作、根瘤菌应用等方面的最新进展，附录还包括根瘤菌分子生态学的研究方法，是一部了解我国及世界上根瘤菌分类、进化、生态学、基因组学、根瘤菌与豆科植物互作研究进展的最新参考书。

书的摘要：This book reviews the history and development of rhizobial ecology (diversity, function and interactions with the biotic and abiotic environments), evolution (genome diversification, systematics of symbiotic genes) and application. Further, it describes the new concept of rhizobia, the latest systematic methods, biogeographic study methods, and genomic studies to identify the interactions between rhizobia, legumes and environments. To enable readers to gain a comprehensive understanding of rhizobial biogeography, the book provides effective protocols for the selection and application of high-efficiency rhizobial inoculants. In addition, it presents standard and modern methods used in studies on rhizobial ecology and evolution in dedicated appendices, making it a unique and valuable handbook for researchers. © Springer Nature Singapore Pte Ltd. 2019.

陈文新院士做的序：

Traditionally, the term ‘rhizobia’ refers to a special group of soil bacteria that can induce root and/or stem nodules on legume plants and reduce dinitrogen (N₂) into ammonia (NH₃) inside the nodules. The nodule symbiosis of rhizobia-leguminous plants is the most efficient biological nitrogen-fixing system on the planet. Based upon their important ecological and economic impacts, rhizobia have been studied for about one and half centuries, and the legume-rhizobium symbiosis has been applied for improving the growth of plants since the ancient time, even before rhizobia were recognised. According to the ancient literature, the legume-rhizobium symbiosis was applied 2000 years ago in China for maintaining the soil fertility by rotation or intercropping of the legumes (soybean, green gram and red mung bean) with the grain crops (wheat, rice or millet), although the mechanism (biological nitrogen fixation) was unknown. Currently, it is known that rhizobia can not only fix nitrogen in the symbiosis with legumes, but can also colonise many plant species other than their symbiotic hosts as endophytes to improve the growth and productivity of the plants by different mechanisms, like solubilizing mineral compounds, production of phytohormones, etc. Therefore, rhizobia are one of the most important bioresources and a good model for investigation of the ecological interactions among the bacteria, plants and environmental factors.

As with many other scientific researches, the development of study on rhizobia was dependent on the production requirements and was closely related to the developments of other scientific disciplines. To understand the mechanism by which legumes could improve the soil fertility, the early scientists in the 1800s performed studies and noticed the relation between root nodules on the legume crops and their fertility impact. Due to the development of microbial culturing, Beijerink (1888) isolated the first nodule bacterium from pea nodules. Related to the petroleum crisis erupted in the 1970’s, biological nitrogen fixation was a hot point for investigation, and many studies have investigated the diversity, genetics, physiochemical properties, ecology and application of rhizobia. By the previous studies accompanying the application of novel methodology in different eras, the mechanisms of rhizobial specificity for host legumes (nodulation genes and their expression/regulation) and of their capability for nitrogen fixation (nitrogen-fixing genes and their expression/ regulation, structure and activity of nitrogenase) have been clearly described at the molecular level. Also, knowledge about the diversity and evolution of rhizobia has been greatly improved; for example, more than 100 symbiotic rhizobial species have been described in about 15 genera belonging to Alphaproteobacteria and Betaproteobacteria classes.

The previous studies on rhizobia have answered many scientific questions but also generated some new ones. Furthermore, the current ecological problems, such as the global climate change and environmental contamination caused by the excessive application of chemical fertilisers and mining activities, require more investigations into the ecology and application of rhizobia. During the past 40 years, our research groups have worked continuously on rhizobial diversity, ecology and application. In this book, we would like to make a resume of our work and share all of our experience and ideas for future study on rhizobia. To make this happen, I am happy to have my former PhD students and colleagues Prof. En Tao Wang (Chaps. 1, 2, 3 and 11), Assoc. Prof. Wen Feng Chen (Chaps. 5, 7, 8, 9 and 10), and Prof. Chang Fu Tian (Chaps. 4 and 6) to be involved in preparing this book. I would also like to thank my longtime friend Prof. J. Peter W. Young for his contribution to this book (Chaps. 4, 6 and book review).