Joe C. Polacco is Professor of Biochemistry in the Department of Biophysics and Center of Biotechnology at the Universidade Federal do Rio Grande do Sul. Christopher D. Todd is Assistant Professor in the Department of Biology at the University of Saskatchewan.

"This interesting volume has 17 chapters, each written by one or more acknowledged experts in their field, grouped into five sections." (Journal of Experimental Agriculture, 2012)

• Contributors. Preface.Section 1 The Nitrogen Cycle.1 The New Global Nitrogen Cycle (Jan Willem Erisman).Section 2 Plant-Soil Microbe Interactions.2 Plant Associations with Mycorrhizae and Rhizobium—Evolutionary Origins and Divergence of Strategies in Recruiting Soil Microbes (Gerben Bijl, Stéphane De Mita, and René Geurts).3 Arbuscular Mycorrhizas and N Acquisition by Plants (Luisa Lanfranco, Mike Guether, and Paola Bonfante).4 Ectomycorrhiza and Nitrogen Provision to the Host Tree (Michel Chalot and Claude Plassard).5 Proteins in the Rhizosphere: Another Example of Plant-Microbe Exchange (Clelia De-la-Peña and Jorge M. Vivanco).6 Actinorhizal Symbioses (Katharina Pawlowski).7 Two in the Far North: The Alder-Frankia Symbiosis, with an Alaskan Case Study (Mike Anderson).8 The Path of Rhizobia: From a Free-Living Soil Bacterium to Root Nodulation (Pedro F. Mateos, Raúl Rivas, Marta Robledo, Encarna Velázquez, Eustoquio Martínez-Molina, and David W. Emerich).9 Exploiting Mycorrhizae and Rhizobium Symbioses to Recover Seriously Degraded Soils (Sérgio Miana de Faria, Alexander S. Resende, Orivaldo J. Saggin Júnior, and Robert M. Boddey).Section 3 Epi- and Endo-Phytic Microbes.10 Nitrogen: Give and Take from Phylloplane Microbes (Mark A. Holland).11 N2-Fixing Endophytes of Grasses and Cereals (Veronica Massena Reis, Jos Vanderleyden, and Stijn Spaepen).Section 4 Arthropods.12 Effects of Insect Herbivores on the Nitrogen Economy of Plants (Leiling Tao and Mark D. Hunter).13 Plant Defense Proteins That Inhibit Insect Peptidases (Carlos Peres Silva and Richard Ian Samuels).14 Nutrient Acquisition and Concentration by Ant Symbionts: The Incidence and Importance of Biological Interactions to Plant Nutrition (Cynthia L. Sagers).Section 5 Environmental Signalling in N Acquisition.15 The Functions of Flavonoids in Legume-Rhizobia Interactions (Oliver Yu and Yechun Wang).16 Plant Hormones and Initiation of Legume Nodulation and Arbuscular Mycorrhization (Arijit Mukherjee and Jean-Michel Ané).17 Nitric Oxide as a Signal Molecule in Intracellular and Extracellular Bacteria-plant Interactions (Andrés Arruebarrena Di Palma, Lorenzo Lamattina, and Cecilia M. Creus).Index.