Plants and animals have evolved ever since their appearance in a largely microbial world. Their own cells are less numerous than the microorganisms that they host and with whom they interact closely. The study of these interactions, termed microbial symbioses, has benefited from the development of new conceptual and technical tools. We are gaining an increasing understanding of the functioning, evolution and central importance of symbiosis in the biosphere. Since the origin of eukaryotic cells, microscopic organisms of our planet have integrated our very existence into their ways of life. The interaction between host and symbiont brings into question the notion of the individual and the traditional representation of the evolution of species, and the manipulation of symbioses facilitates fascinating new perspectives in biotechnology and health. Recent discoveries show that association is one of the main properties of organisms, making a more integrated view of biology necessary. Microbial Symbioses provides a deliberately “symbiocentric outlook, to exhibit how the exploration of microbial symbioses enriches our understanding of life, and the potential future for this discipline. Offers a concise summary of the most recent discoveries in the field Shows how symbiosis is acquiring a central role in the biology of the 21st century by transforming our understanding of living things Presents scientific issues, but also societal and economic related issues (biodiversity, biotechnology) through examples from all branches of the tree of life

Rhizobia are bacteria which inhabit the roots of plants in the pea family and "fix" atmospheric nitrogen for plant growth. They are thus of enormous economic importance internationally and the subject of intense research interest. Handbook for Rhizobia is a monumental book of practical methods for working with these bacteria and their plant hosts. Topics include the general microbiological properties of rhizobia and their identification, their potential as symbionts, methods for inoculating rhizobia onto plants, and molecular genetics methods for Rhizobium in the laboratory. The book will be invaluable to Rhizobium scientists, soil microbiologists, field and laboratory researchers at agricultural research centers, agronomists, and crop scientists.

Nitrogen fixation in intact nodulated plants; Anatomy and structure of nodules; Properties of N2-fixing nodules: studies with intact of sliced detached nodules; Bacterioids; Functions of host cells in nodules; Leghaemoglobin; Integrated metabolism in nodules.

During the past three decades there has been a large amount of research on biological nitrogen fixation, in part stimulated by increasing world prices of nitrogen-containing fertilizers and environmental concerns. In the last several years, research on plant--microbe interactions, and symbiotic and asymbiotic nitrogen fixation has become truly interdisciplinary in nature, stimulated to some degree by the use of modern genetic techniques. These methodologies have allowed us to make detailed analyses of plant and bacterial genes involved in symbiotic processes and to follow the growth and persistence of the root-nodule bacteria and free-living nitrogen-fixing bacteria in soils. Through the efforts of a large number of researchers we now have a better understanding of the ecology of rhizobia, environmental parameters affecting the infection and nodulation process, the nature of specificity, the biochemistry of host plants and microsymbionts, and chemical signalling between symbiotic partners. This volume gives a summary of current research efforts and knowledge in the field of biological nitrogen fixation. Since the research field is diverse in nature, this book presents a collection of papers in the major research area of physiology and metabolism, genetics, evolution, taxonomy, ecology, and international programs.

Rhizosphere biology is approaching a century of investigations wherein growth-promoting rhizomicroorganisms (PGPR) have attracted special attention for their ability to enhance productivity, profitability and sustainability at a time when food security and rural livelihood are a key priority. Bio-inputs - either directly in the form of microbes or their by-products - are gaining tremendous momentum and harnessing the potential of agriculturally important microorganisms could help in providing low-cost and environmentally safe technologies to farmers. One approach to such biologically-based strategies is the use of naturally occurring products such as PGPR. Written by an international team of experts, this book considers new concepts and global issues in biopesticide research and evaluates the implications for sustainable productivity. It is an invaluable resource for researchers in applied agricultural biotechnology, microbiology and soil science, and also for industry personnel in these areas.

There has been a resurgence of interest in environmental friendly, sustainable and organic cultural practices that warrants high yield and quality in agricultural crops. To enhance sustainable agricultural production and alleviate food scarcity, spoor of majority of microorganisms, especially plant growth and health promoting bacteria of eminent characteristics that allow them for exploitation in agro-ecosystem. Plant growth promoting rhizobacteria are the soil bacteria inhabiting around/on the root surface and are directly or indirectly involved in promoting plant growth and development via production and secretion of various regulatory chemicals in the vicinity of rhizosphere. Among various beneficial bacteria mediated mechanisms include direct production of phytohormones and biosurfactants experiencing quest of research and concept up gradation that can built emerging paradigm (agriculture model). Research on bacteria-mediated phytohormones is crucially important, provides key understanding of the plant growth and development. Various genera including PGPR group of bacteria are potential source of plant growth regulators. Application of such organism allow plants to survive under abiotic and biotic stress conditions besides govern phytohormone mediated immune response and manage to regulate hormones. Such group of bacteria also produce another important metabolite i.e. biosurfacatants which are involved in many important functions to bacteria itself as we ll as for the plants and their ecosystem. Biosurfactants may alter nutrient availability, endogenous metabolites such as antibiotics production, root colonization imparting protection from phytopathogens besides eradicating soil contaminants and other pollutants. The role and activities of surfactants produced by bacteria are multifarious in nature. Thus, bacterial phytohormones and biosurfactants are identified as effector molecules in plant- microbe interactions, in pathogenesis and phyto-stimulation which can either be beneficial for the bacteria itself or for the crops. This book highlights current applications and research on bacterial hormones and surfactants to provide a timely overview. The chapters have been contributed by subject experts from around the world and include topics of varied importance which include phytohormones production by rhizospheric and endophytic bacteria, their role in rhizosphere competence, plant growth regulation, bioremediation, biosurfactants as antibiofilm agents and other aspects. This major new work represents a valuable source of information to all those scientists interested in microbial technology with respect to the microbial innovative products and applications towards sustainable agroecosystem.