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The halobacteria are the only organisms that are tolerant of salinity at the molecular level. All other bacteria, all fungi, all plants, and all animals avoid the need for salt tolerance for most of their macromolecules by maintaining defined and conserved conditions in the cytoplasm. These conditions favour potassium over sodium, the limitation of total inorganic ion activity, and the supplementation of this where necessary with organic solutes which are metabolically neutral osmolytes that may also be osmoprotectant. The salt tolerance of an organism depends upon the range of external salinity over which it is able to sustain these conditions in the cytoplasm. There is substantial and increasing knowledge of the molecular biology and molecular genetics of the processes of ion and organic solute transport, solute synthesis, and compartmentation that underpin cell-based tolerance. Much of recent research focuses on the identification of genes and gene products that affect cell-based tolerance, commonly derived from single-cell models. There is commonly the implicit or explicit assumption that incorporation of these genes will benefit the salt tolerance of food crop species. While this essential experimental approach is giving enormous insight there should not be rash or premature expectations. The unique and overriding consideration for the salinity tolerance of terrestrial plants is the net flux of water due to transpiration and so resides at a higher level of organization. Processes that are advantageous to a single cell in an aqueous medium may be lethal to a cell in a leaf in the air. The likely impact of single structural-gene changes in ion and solute transport upon co-ordinated plant response is probably overestimated, and recent views consider regulatory processes and multiple gene transfers. While the tech nical ability for plant transformation increases daily, the practicality of using transgenic plants in complex breeding programmes seems rarely to be given enough thought. If intervention at the molecular level is to lead to salt-tolerant crop plants then it will be essential to view this in the contexts of whole plants and of plant breeding. Recent indications that a relatively small number of quantitative trait loci (QTL) may govern complex physiological characters offer the most hope for the future.

A: Introduction. 1. The plant hormones: Their nature, occurrence, and functions P.J. Davies. 2. The plant hormone concept: Concentration, and sensitivity and transport P.J. Davies. B: Hormone Synthesis and Metabolism. 1. Auxin biosynthesis and metabolism R.S. Bandurski, J.D. Cohen, J. Slovin, D.M. Reinecke. 2. Gibberellin biosynthesis and metabolism V.M. Sponsel. 3.Cytokinin biosynthesis and metabolism B.A. McGaw. 4. Biosynthesis and metabolism of ethylene T.A. McKeon, J.C. Fernandez-Maculet, S.F. Yang. 5. Abscisic acid biosynthesis and metabolism D.C. Walton. C: Other Hormonal Compounds. 1. Polyamines as endogenous growth regulators A.W. Galston, R. Kaur-Sawhney. 2. Jasmonates, salicylic acid and brassinosteroids P.E. Staswick, I. Raskin, R.N. Arteca. D: How Hormones Work. 1. Auxin and cell elongation R.E. Cleland. 2. The control of gene expression by auxin G. Hagen. 3. Gibberellin action in germinating cereal grains J.V. Jacobsen, F. Gubler, P.M. Chanderl. 4. Hormone binding and signal transduction K.R. Libbenga, A.M. Mennes. 5. Calcium and plant hormone action P.C. Bethke, S. Gilroy, R.L. Jones. E: Molecular Aspects of Hormone Synthesis and Action. 1. Genes specifying auxin and cytokinin biosynthesis in prokaryotes R.O. Morris. 2. Transgenic plants in hormone biology H.J. Klee, M.B. Lanahan. 3. Biochemical and genetic approaches to study the mechanism of action of auxins J. Schell, K. Palme, R. Walden. 4. Ethylene genes and fruit ripening S. Picton, J.E. Gray, D. Grierson. 5. The role of hormones in gene activation in response to wounding H. Pena-Cortes, L. Willmitzer. F: Hormone Analysis. 1.Instrumental methods of plant hormone analysis R. Horgan. 2. Immunoassay methods of plant hormone analysis J.L. Caruso, V.C. Pence, L.A. Leverone. G: The Functioning of Hormones in Plant Growth and Development. 1. Hormone mutants and plant development J.B. Reid, S.H. Howell. 2. Ethylene in plant growth, development, and senescence M.S. Reid. 3. Auxin transport T.L. Lomax, G.K. Muday, P.H. Rubery. 4. The induction of vcascular tissues by auxin R. Aloni. 5. Hormones and the orientation of growth P.B. Kaufman, L-L. Wu, T.G. Brock, D. Kim. 6. Hormonal regulation of apical dominance I.A. Tamas. 7. Hormones as regulators of water balance T.A. Mansfield, M.R. McAinsh. 8. Hormones and reproductive development J.D. Metzger. 9. The role of hormones in photosynthate partitioning and seed filling M.L. Brenner, N. Cheikh. 10. The role of hormones during seed development C.D. Rock, R.S. Quatrano. 11. The role of hormones in potato (Solanum tuberosum L.) tuberization E.E. Ewing. 12. Postharvest hormone changes in vegetables and fruit P.M. Ludford. 13. Hormones in tissue culture and micropropagation A.D. Krikorian. 14. Natural and synthetic growth regulators and their use in horticultural and agronomic crops T.J. Gianfagna.

Since its publication in 2000, Biochemistry & Molecular Biology of Plants, has been hailed as a major contribution to the plant sciences literature and critical acclaim has been matched by global sales success. Maintaining the scope and focus of the first edition, the second will provide a major update, include much new material and reorganise some chapters to further improve the presentation. This book is meticulously organised and richly illustrated, having over 1,000 full-colour illustrations and 500 photographs. It is divided into five parts covering: Compartments: Cell Reproduction: Energy Flow; Metabolic and Developmental Integration; and Plant Environment and Agriculture. Specific changes to this edition include: Completely revised with over half of the chapters having a major rewrite. Includes two new chapters on signal transduction and responses to pathogens. Restructuring of section on cell reproduction for improved presentation. Dedicated website to include all illustrative material. Biochemistry & Molecular Biology of Plants holds a unique place in the plant sciences literature as it provides the only comprehensive, authoritative, integrated single volume book in this essential field of study.

Part 1 The control of metabolism: fundamentals of gene structure and control, D.D.Lefebvre regulation of gene expression during development, R.Casey biochemical regulation, W.Plaxton regulation by compartmentation, D.T.Dennis and M.J.Emes. Part 2 Cytosolic carbon metabolism: carbohydrates synthesis and degradation, N.J.Kruger glycolysis, the oxidative pentose phosphate pathway and anaerobic respiration, J.A.Miernyk. Part 3 Mitochondrial metabolism: mitochondrial structure, W.Newcomb carbon metabolism in mitochondria, T.ap Rees oxidation of mitochondrial NADH and the synthesis of ATP, H.Lambers. Part 4 Mitochondrial-cytosol interaction: the mitochondrial genome and its expression, M.Gray protein import into the mitochrondrion, K.Freeman et al metabolite exchange between the mitochondrion and the cytosol, R.Douce and M.Neuburger. Part 5 Photosynthesis: plastid structure and development, W.Newcomb molecular biology of photosynthesis in higher plants, J.Mullet the formation of ATP and reducing power in the light, N.Nelson and B.Prezelin ribulose 1, 5-bisphosphate carboxylase/oxygenese - mechanisms, activation and regulation, R.G.Jensen the reductive pentose phosphate pathway and its regulation, F.D.Macdonald and B.B.Bucchanan photorespiration and CO2-concentrating mechanisms, D.T.Canvin the flux of metabolites in C4 and CAM plants, R.C.Leegood and C.B.Osmond. Part 6 Chloroplast-cytosol interactions: transport of proteins into chloroplasts, K.Keegstra the flux of carbon between the chloroplast and the cytosol, M.Stitt. Part 7 The formation and breakdown of lipids: the structure and formation of microbodies, C.Halpin and M.Lord fatty acid and lipid biosynthesis and degradation, J.E.Andrews and J.Ohlrogge terpene biosynthesis and metabolism, C.A.West. Part 8 Nitrogen metabolism: molecular biology of N metabolism, C.Vance and S.M.Griffith amino acid and ureide biosynthesis, R.Ireland interactions between nitrogen assimilation, photosynthesis and respiration, D.H.Turpin and H.G.Weger long distance transport of carbon and nitrogen from sources to sink in higher plants, M.Peoples and R.Gifford protein turnover, P.M.Hatfield and R.D.Vierstra protein storage and utilization in seeds, J.D.Bewley and J.S.Greenwood. Part 9 Prospects for plant improvement: fundamentals of gene transfer in plants, B.Miki and V.N.Iyer biochemical basis for plant improvement, C.R.Somerville.

Preface. Color Plates. 1. Molecular Evolutionary Systematics of the Rhizobiaceae P. van Berkum, B.D. Eardly. 2. General Genetic Knowledge M.F. Hynes, T.M. Finan. 3. Outer Membrane Proteins B.J.J. Lugtenberg. 4. Phospholipids and Alternative Membrane Lipids O. Geiger. 5. Cell-Surface beta-Glucans M.W. Breedveld, K.J. Miller. 6. Production of Exopolysaccharides A. Becker, A. Puhler. 7. Lipopolysaccharides and K-Antigens: Their Structures, Biosynthesis and Functions E.L. Kannenberg, et al. 8. Soil Biology of the Rhizobiaceae M.J. Sadowsky, P.H. Graham. 9. Opines and Opine-Like Molecules Involved in Plant-Rhizobiaceae Interactions Y. Dessaux, et al. 10. Conjugal Plasmids and Their Transfer S.K. Farrand. 11. Attachment of Rhizobiaceae to Plant Cells A.G. Matthysse, J.W. Kijne. 12. The Agrobacterium Oncogenes A.N. Binns, P. Costantino. 13. Organization and Regulation of Expression of the Agrobacterium Virulence Genes T.M. Johnson, A. Das. 14. Function of the Ti-Plasmid Vir Proteins: T-Complex Formation and Transfer to the Plant Cell F. de la Cruz, E. Lanka. 15. Role of Virulence Proteins of Agrobacterium in the Plant L. Rossi, et al. 16. Determinants of Host Specificity of Agrobacterium and their Function Wanyin Deng, E.W. Nester. 17. The Use of Agrobacterium for Plant Genetic Engineering K. D'Halluin, J. Botterman. 18. Diversity of Root Nodulation andRhizobial Infection Processes A.-E. Hadri, et al. 19. Genetic Organization and Transcriptional Regulation of Rhizobial Nodulation Genes H.R.M. Schlaman, et al. 20. Functions of Rhizobial Nodulation Genes J.A. Downie. 21. Responses of the Plant to Nod Factors A.-E. Hadri, T. Bisseling. 22. Tissue and Cell Invasion by Rhizobium: The Structure and Development of Infection Threads and Symbiosomes N.J. Brewin. 23. A Survey of Symbiotic Nitrogen Fixation by Rhizobia P.A. Kaminski, et al. 24. Carbon and Nitrogen Metabolism in Rhizobia M.L. Kahn, et al. 25. Evolutionary Aspects of Symbiotic Adaptations, Rhizobium's Contribution to Evolution by Association A. Quispel. 26. Legume Symbiotic Nitrogen Fixation: Agronomic Aspects C.P. Vance. Contributors. Abbreviations. Subject Index.

In many temperate plant species, a period of exposure to a low positive temperature will acclimate the plants to withstand a subsequent freezing stress. A number of plant genes, which are up-regulated at steady-state mRNA levels by an acclimation treatment, have been isolated from both monocotyledon and dicotyledon species. Most of these genes are also responsive to a drought treatment and/or abscisic acid. The acclimation of plants to freezing stress is a complex process and although genetic studies in some species have identified genes with a major effect, in general, the inheritance of frost tolerance is multigenic. In view of this, it is not surprising that a range of different genes have been cloned. The precise function of the proteins encoded by these genes is unknown. However, analysis of predicted protein products and studies of recombinant proteins, together with detailed expression studies, are beginning to provide information about some of the genes. Both transcriptional and post-transcriptional controls have been shown to be involved in the expression of these genes. Although studies of RNA stabilizing systems are still in their early stages, a number of low temperature responsive promoters have been studied using reporter gene constructs. Other approaches to the molecular analysis of cold acclimation include the isolation of non-acclimating mutants and the production of transgenic plants.

Over the last decade, considerable advances have occurred in understanding the molecular biology and biophysics of water permeation across plant membranes and tissues. Spurred on by the rapid advances in cloning and functional characterization of a superfamily of major intrinsic proteins, some of which function as aquaporins, the biophysics of transport of water and small non-electrolytes across plant membranes is being re-examined based on the proposed function of these membrane-integral proteins in their native membranes. This review focuses on a number of issues that are central to an understanding of aquaporin function: (1) the need to be able to test for water-channel activity in native membranes; (2) the implications of the observed solute/water selectivity of aquaporins; (3) the putative functional roles of aquaporins at the cell, tissue and organ levels in plants; and (4) information that can be obtained from studies of the abundance, diversity and expression patterns of aquaporins. It is clear that to answer many of the critical questions that remain concerning aquaporin function, combined studies using appropriate molecular and biophysical techniques will be required.

In the past few decades, many investigations in the field of plant biology have employed selectively neutral, multilocus, dominant markers such as inter-simple sequence repeat (ISSR), random-amplified polymorphic DNA (RAPD), and amplified fragment length polymorphism (AFLP) to address hypotheses at lower taxonomic levels. More recently, sequence-related amplified polymorphism (SRAP) markers have been developed, which are used to amplify coding regions of DNA with primers targeting open reading frames. These markers have proven to be robust and highly variable, on par with AFLP, and are attained through a significantly less technically demanding process. SRAP markers have been used primarily for agronomic and horticultural purposes, developing quantitative trait loci in advanced hybrids and assessing genetic diversity of large germplasm collections. Here, we suggest that SRAP markers should be employed for research addressing hypotheses in plant systematics, biogeography, conservation, ecology, and beyond. We provide an overview of the SRAP literature to date, review descriptive statistics of SRAP markers in a subset of 171 publications, and present relevant case studies to demonstrate the applicability of SRAP markers to the diverse field of plant biology. Results of these selected works indicate that SRAP markers have the potential to enhance the current suite of molecular tools in a diversity of fields by providing an easy-to-use, highly variable marker with inherent biological significance.

Nicotiana benthamiana is a widely used model plant species for the study of fundamental questions in molecular plant-microbe interactions and other areas of plant biology. This popularity derives from its well-characterized susceptibility to diverse pathogens and, especially, its amenability to virus-induced gene silencing and transient protein expression methods. Here, we report the generation of a 63-fold coverage draft genome sequence of N. benthamiana and its availability on the Sol Genomics Network for both BLAST searches and for downloading to local servers. The estimated genome size of N. benthamiana is 3 Gb (gigabases). The current assembly consists of approximately 141,000 scaffolds, spanning 2.6 Gb with 50% of the genome sequence contained within scaffolds >89 kilobases. Of the approximately 16,000 N. benthamiana unigenes available in GenBank, >90% are represented in the assembly. The usefulness of the sequence was demonstrated by the retrieval of N. benthamiana orthologs for 24 immunity-associated genes from other species including Ago2, Ago7, Bak1, Bik1, Crt1, Fls2, Pto, Prf, Rar1, and mitogen-activated protein kinases. The sequence will also be useful for comparative genomics in the Solanaceae family as shown here by the discovery of microsynteny between N. benthamiana and tomato in the region encompassing the Pto and Prf genes.

Contents : 1. A leaf cell consists of several metabolic compartments -2. The use of energy from sunlight by photosynthesis -3. Photosynthesis is an electron transport process -4. ATP generation by photosynthesis -5. Mitochondria, the power stations of cell -6. Photosynthetic CO2 assimilation by the Calvin cycle -7. Photorespiration -8. Photosynthesis and water consumption -9. Polysaccharides -10. Nitrate assimilation -11. Nitrogen fixation -12. Sulfate assimilation -13. Phloem transport -14. Plant storage proteins -15. Glycerolipids -16. The function of secondary metabolites in plants -17. Isoprenoids -18. Phenylpropanoids -19. Signals regulating the growth and development of plant organs -20. The genomes of plant cells -21. Protein biosynthesis -22. Gene technology in plants.

This review first summarizes the diverse nature of isoprenoids found in plants, emphasizing the wide range of physiological functions these compounds serve. The biosynthetic origins of isoprenoids have occupied chemists and biochemists for decades, and the second section of this review recaps some of the conceptual models used to rationalize key biosynthetic reactions in the isoprenoid pathway. The third section describes briefly some of the recently developed experimental systems that have helped researchers uncover much of the biochemistry and molecular biology of isoprenoids. The fourth section compares the deduced amino acid sequences of enzymes with similar catalytic functions and attempts to correlate these sequences with the known enzymology. The fifth and final section focuses on our limited understanding of how isoprenoid biosynthesis is regulated in plants.

Techniques for studying cell and gene function in plants are growing rapidly in power and sophistication. A course for investigators who are familiar with molecular biology and want to use plants as experimental organisms has been held at Cold Spring Harbor since 1981. This manual, the first published compilation of methods from the course since 1985, presents current methods in gene technology that are taught in the course, applied to higher plants. Complete step-by-step protocols are given, with full descriptions of the materials required, clear advice on trouble-shooting and discussion of the rationale and application of the methods chosen.

This review summarizes current knowledge about genes whose products function in the transport of various cationic macronutrients (K, Ca) and micronutrients (Cu, Fe, Mn, and Zn) in plants. Such genes have been identified on the basis of function, via complementation of yeast mutants, or on the basis of sequence similarity, via database analysis, degenerate PCR, or low stringency hybridization. Not surprisingly, many of these genes belong to previously described transporter families, including those encoding Shaker-type K+ channels, P-type ATPases, and Nramp proteins. ZIP, a novel cation transporter family first identified in plants, also seems to be ubiquitous; members of this family are found in protozoa, yeast, nematodes, and humans. Emerging information on where in the plant each transporter functions and how each is controlled in response to nutrient availability may allow creation of food crops with enhanced mineral content as well as crops that bioaccumulate or exclude toxic metals.

This review focuses on the monoterpene, sesquiterpene, and diterpene synthases of plant origin that use the corresponding C10, C15, and C20 prenyl diphosphates as substrates to generate the enormous diversity of carbon skeletons characteristic of the terpenoid family of natural products. A description of the enzymology and mechanism of terpenoid cyclization is followed by a discussion of molecular cloning and heterologous expression of terpenoid synthases. Sequence relatedness and phylogenetic reconstruction, based on 33 members of the Tps gene family, are delineated, and comparison of important structural features of these enzymes is provided. The review concludes with an overview of the organization and regulation of terpenoid metabolism, and of the biotechnological applications of terpenoid synthase genes.

Meiosis is the cell division that reshuffles genetic information between generations. Recently, much progress has been made in understanding this process; in particular, the identification and functional analysis of more than 80 plant genes involved in meiosis have dramatically deepened our knowledge of this peculiar cell division. In this review, we provide an overview of advancements in the understanding of all aspects of plant meiosis, including recombination, chromosome synapsis, cell cycle control, chromosome distribution, and the challenge of polyploidy.

The aerial surfaces of plants are covered with a wax layer that is primarily a waterproof barrier but that also provides protection against environmental stresses. The ubiquitous presence of cuticular wax is testimony to its essential function. Genetic and environmental factors influence wax quantity and composition, which suggests that it is an actively regulated process. The basic biochemistry of wax production has been elucidated over the past three decades; however, we still know very little about its regulation. This review presents a discussion along with new perspectives on the regulatory aspects of wax biosynthesis. Among the topics discussed are the partitioning of fatty acid precursors into wax biosynthesis and the elongation of fatty acids with particular emphasis on the nature of the acyl primer, and the role of ATP in fatty acid elongation. The recent cloning of wax biosynthetic genes and the transport of wax to plant surfaces are also discussed.

- ions and to some extent Cl - and SO 4 2 - of Mg 2+ and nutrient imbalance caused by excess of Na + and Cl - ions. Salinity stress response is multigenic, as a number of processes i n- volved in the tolerance mechanism are affected, such as var ious compatible solutes/osmolytes, polyamines, reactive oxygen species and antioxidant defence mecha- nism, ion transport and compartmentalization of inj u- rious ions. Various genes/cDNAs encoding proteins involved in the above-mentioned processes have been identified and isolated. The role of genes/cDNAs e n- coding proteins involved in regulating other genes/ pro- teins, signal transduction process involving hormones like ABA, JA and polyamines, and strategies to i mprove salinity stress tolerance have also been di scussed. EXCESS amount of salt in the soil adversely affects plant growth and development. Nearly 20% of the world's cul- tivated area and nearly half of the world's i rrigated lands are affected by salinity 1