Symbiotic Nitrogen Fixation


Book Description

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.




Plant-Rhizobia Symbiosis and Nitrogen Fixation in Legumes


Book Description

The reciprocal exchange of chemical signals between legume and rhizobium leads to the establishment of Root Nodule Symbiosis (RNS). The discoveries of the Nodulation Factor (NF) and nod genes, along with the discoveries of the relevant genetic plant factors, have expanded our understanding of how legume-rhizobial interactions constitute a successful mutualistic symbiosis. Symbiotic nodule formation can be divided into the following molecular events: (i) the reciprocal exchange of signals; (ii) epidermal recognition of symbiotic partner and infection thread formation; (iii) nodule organogenesis; (iv) the establishment of a microaerophilic environment to provide nitrogenase the ideal condition to work; and, (v) modulation of immunity to host rhizobium inside the nodule cells. The number of nodules in a plant is maintained via a process of systemic signaling, known as ‘autoregulation of nodulation’ (AON), that acts as a negative signal to control nodule number in low nitrogen conditions and inhibit nodule initiation in an optimally nitrogen-fed plant. Over 200 plant genes have been discovered up to now and these discoveries have given us a broad understanding of RNS.




Regulation of Nitrogen-Fixing Symbioses in Legumes


Book Description

The Nitrogen-Fixing Legume-Rhizobium Symbiosis, Volume 94, the latest release in the Advances in Botanical Research series, highlights new advances in the field, with this new volume presenting interesting chapters on The diversity of legume-rhizobium symbioses, Parasponia; an evolutionary outlier of rhizobium symbiosis, Rhizobium diversity in the light of evolution, Genomes of rhizobia, Gene regulation by extracytoplasmic function (ECF) sigma factors in alpha-rhizobia, Early symbiotic signaling between Plant and Bacteria, Rhizobia infection, a journey to the inside of plant cells, Differentiation of symbiotic nodule cells and their rhizobium endosymbionts, Nodule Organogenesis, Nitrogen Fixation by the Legume-Rhizobium Symbiosis, and much more. - Provides the authority and expertise of leading contributors from an international board of authors - Presents the latest release in the Advances in Botanical Research series - Updated release includes the latest information on the Nitrogen-Fixing Legume-Rhizobium Symbiosis




Handbook for Rhizobia


Book Description

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.




Biological Nitrogen Fixation


Book Description

Phylogenetic classification of nitrogen-fixing organisms. Physiology of nitrogen fixation in free-living heterotrophs. Nitrogen fixation by photosynthetic bacteria. Nitrogen fixation in cyanobacteria. Nitrogen fixation by methanogenic bacteria. Associative nitrogen-fixing bacteria. Actinorhizal symbioses. Ecology of bradyrhizobium and rhizobium. The rhizobium infection process. Physiology of nitrogen-fixing legume nodules: compartments, and functions. Hydrogen cycling in symbiotic bacteria. Evolution of nitrogen-fixing symbioses. The rhizobium symbiosis of the nonlegume parasponia. Genetic analysis of rhizobium nodulation. Nodulins in root nodule development. Plant genetics of symbiotic nitrogen fixation. Molecular genetics of bradyrhizobium symbioses. The enzymology of molybdenum-dependent nitrogen fixation. Alternative nitrogen fixation systems. Biochemical genetics of nitrogenase. Regulation of nitrogen fixation genes in free-living and symbiotic bacteria. Isolated iron-molybdenum cofactor of nitrogenase.




Technical Handbook on Symbiotic Nitrogen Fixation


Book Description

General information on the symbiotic nitrogen fixation. Isolation, identification and counting of rhizobia. Production of an inoculant and inoculation of legumes. Experiments.




Symbiotic Nitrogen Fixation in Plants


Book Description

Genetical aspects and taxonomy; Quality of legume inoculants; Field experiments on nitrogen fixation by nodulated legumes; Legume nitrogen fixation and the environment; Nitrogen fixing symbioses in non-leguminous plants.




Nitrogen-fixing Leguminous Symbioses


Book Description

Nodules produced on legume roots by root-nodule bacteria provide the major nitrogenous input into natural and agricultural systems worldwide. This book provides an in-depth and up-to-the-minute analysis of what is known about this symbiosis, its origins, the process of nodule formation and development, and the biochemistry and genetics of nodular nitrogen fixation. It also reviews the physiology of the root-nodule bacteria themselves, their ecology in both natural and agricultural systems, and how we can introduce new legumes along with the bacteria they require. This book is recommended for scientists working with root nodule bacteria or host legumes, agronomists, forestry scientists, and soil scientists.




Current Issues in Symbiotic Nitrogen Fixation


Book Description

In the 100 years since the legume-Rhizobium symbiotic nitrogen fixation interaction was first described, interest in this field has grown rapidly. The types of studies have been cyclical in nature, involving a cross-section of disciplines. The availability of cheap nitrogenous fertilizers caused much of the biological nitrogen fixation research to become more theoretical in the developed world. The high cost of energy, coupled with environmental concerns and the interest in sustainable agriculture, has stimulated research in symbiotic nitrogen fixation. The development of modern genetic techniques has resulted in interdisciplinary research on plant-microbe interactions controlling nitrogen fixation. This has resulted in a better understanding of environmental factors influencing the nodulation process, chemical signalling between the symbiotic partners and the nature of the specificity between host plant and microsymbiotant. This volume summarizes the diverse research efforts in biological nitrogen fixation by presenting a collection of papers in the areas of physiology and metabolism, taxonomy and evolution, genetics and ecology.




Rhizobium Biology and Biotechnology


Book Description

This book provides in-depth reviews of the role of Rhizobium in agriculture and its biotechnological applications. Individual chapters explore topics such as: the occurrence and distribution of Rhizobium; phenotypic and molecular characteristics of Rhizobium; impact of Rhizobium on other microbial communities in the rhizosphere; N2-fixation ability of Rhizobium; Rhizobium and biotic stress; Rhizobium-mediated restoration of an ecosystem; in silico analysis of the rhizobia pool; further biotechnological perspectives of Rhizobium.