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




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.




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.




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.




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.




MOLECULAR BIOLOGY OF SYMBIOTIC NITROGEN FIXATION


Book Description

Genetics as a tool to understand structure and function; Vector technology of relevance to nitrogen fixation research; The Azolla-Anabaena symbiosis; The genetics of the Frankia-actinorhizal symbiosis; Legume nodule biochemistry and function; The Rhizobium/bradyrhizobium-legume symbiosis; Nitrate inhibition of nodulation in legumes; Nodulin function and nodulin gene regulation in root nodule development; The Parasponia-bradyrhizobium symbiosis.




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.




Legume Nitrogen Fixation in Soils with Low Phosphorus Availability


Book Description

This thoughtful and provocative book provides a concise, up-to-date presentation of how current and projected future phosphorus scarcity will affect legume growth and their symbiotic nitrogen-fixing capabilities. It is a timely examination of the physiological and molecular responses of nodules to phosphorous deficiency in attempt to identify common principles. Students and researchers in the many disciplines related to crop productivity will find this title an exciting contribution in the area of plant stress physiology. The knowledge in this volume can also aid plant breeders, particularly through new methods of genetic engineering, in developing unique and adaptive cultivars with higher symbiotic efficiency. The awareness of the rapidly rising world population must translate into a parallel increase in agricultural production in order to sustain the growing population both now and in the future. Hence, the demand for food crops to produce proteins and vegetable oil for human consumption is going to increase considerably during the coming years. The essential role of legumes in agriculture is well-recognized, given the abundant levels of proteins and oils found in plants along with their enormous contribution to the sustainability of agricultural systems and human health. The capacity of legumes to fix nitrogen (N2) in partnership with rhizobia provides an input-saving and resource-conserving alternative, thereby reducing the need for chemical fertilizers while enhancing overall crop productivity. The use of N2-fixing legumes to produce plant proteins results in a substantial decrease in the consumption of fossil fuels and therefore also in the agricultural effects to global warming. However, a major constraint to legume production is low soil phosphorus (P) availability, considering that an overwhelming majority of the world’s soils are classified as P-deficient. Low-P availability is especially problematic for legumes, since legume nodules responsible for N2 fixation have a high P requirement. Therefore, this book explains how nodule N2 fixation responds to low P availability, which is crucial for improving legume production and maintaining agricultural sustainability in the context of the global P crisis.




Advances in Biology and Ecology of Nitrogen Fixation


Book Description

Biological nitrogen fixation has essential role in N cycle in global ecosystem. Several types of nitrogen fixing bacteria are recognized: the free-living bacteria in soil or water; symbiotic bacteria making root nodules in legumes or non-legumes; associative nitrogen fixing bacteria that resides outside the plant roots and provides fixed nitrogen to the plants; endophytic nitrogen fixing bacteria living in the roots, stems and leaves of plants. In this book there are 11 chapters related to biological nitrogen fixation, regulation of legume-rhizobium symbiosis, and agriculture and ecology of biological nitrogen fixation, including new models for autoregulation of nodulation in legumes, endophytic nitrogen fixation in sugarcane or forest trees, etc. Hopefully, this book will contribute to biological, ecological, and agricultural sciences.