- Home
- A-Z Publications
- Annual Review of Plant Biology
- Previous Issues
- Volume 48, 1997
Annual Review of Plant Biology - Volume 48, 1997
Volume 48, 1997
- Review Articles
-
-
-
THE C2 OXIDATIVE PHOTOSYNTHETIC CARBON CYCLE
Vol. 48 (1997), pp. 1–25More Less▪ AbstractThe C2 oxidative photosynthetic carbon cycle plus the C3 reductive photosynthetic carbon cycle coexist. Both are initiated by Rubisco, use about equal amounts of energy, must regenerate RuBP, and result in exchanges of CO2 and O2 to establish rates of net photosynthesis, CO2 and O2 compensation points, and the ratio of CO2 and O2 in the atmosphere. These concepts evolved from research on O2 inhibition, glycolate metabolism, leaf peroxisomes, photorespiration, 18O2/16O2 exchange, CO2 concentrating processes, and a requirement for the oxygenase activity of Rubisco. Nearly 80 years of research on these topics are unified under the one process of photosynthetic carbon metabolism and its self-regulation.
-
-
-
-
TRANSPORT OF PROTEINS AND NUCLEIC ACIDS THROUGH PLASMODESMATA
Vol. 48 (1997), pp. 27–50More Less▪ AbstractDespite a potentially key role in cell-to-cell communication, plant intercellular connections—the plasmodesmata—have long been a biological “black box.” Little is known about their protein composition, regulatory mechanisms, or transport pathways. However, recent studies have shed some light on plasmodesmal function. These connections have been shown to actively traffic proteins and protein–nucleic acid complexes between plant cells. This review describes these transport processes—specifically, cell-to-cell movement of plant viruses as well as endogenous cellular proteins—and discusses their possible mechanism(s). For comparison and to provide a broader perspective on the plasmodesmal transport process, the current model for nuclear import, the only other known example of transport of large proteins and protein–nucleic acid complexes through a membrane pore, is summarized. Finally, the function of plasmodesmata as communication boundaries within plant tissue is discussed.
-
-
-
AUXIN BIOSYNTHESIS
Vol. 48 (1997), pp. 51–66More Less▪ AbstractIndole-3-acetic acid (IAA) is the most abundant naturally occurring auxin. Plants produce active IAA both by de novo synthesis and by releasing IAA from conjugates. This review emphasizes recent genetic experiments and complementary biochemical analyses that are beginning to unravel the complexities of IAA biosynthesis in plants. Multiple pathways exist for de novo IAA synthesis in plants, and a number of plant enzymes can liberate IAA from conjugates. This multiplicity has contributed to the current situation in which no pathway of IAA biosynthesis in plants has been unequivocally established. Genetic and biochemical experiments have demonstrated both tryptophan-dependent and tryptophan-independent routes of IAA biosynthesis. The recent application of precise and sensitive methods for quantitation of IAA and its metabolites to plant mutants disrupted in various aspects of IAA regulation is beginning to elucidate the multiple pathways that control IAA levels in the plant.
-
-
-
THE SYNTHESIS OF THE STARCH GRANULE
A. M. Smith, K. Denyer, and C. MartinVol. 48 (1997), pp. 67–87More Less▪ AbstractThis review describes and discusses the implications of recent discoveries about how starch polymers are synthesized and organized to form a starch granule. Three issues are highlighted. 1. The role and importance of ADPglucose pyrophosphorylase in the generation of ADPglucose as the substrate for polymer synthesis. 2. The contributions of isoforms of starch-branching enzyme, starch synthase, and debranching enzyme to the synthesis and ordered packing of amylopectin molecules. 3. The requirements for and regulation of the synthesis of amylose.
-
-
-
CHEMICAL CONTROL OF GENE EXPRESSION
Vol. 48 (1997), pp. 89–108More Less▪ AbstractPromoters that respond to otherwise inactive chemicals will enhance the tools available for analyzing gene function in vivo and for altering defined traits of plants at will. Approaches to provide such tools have yielded plant promoters that respond to compounds activating defense genes. In addition, the transfer of regulatory elements from prokaryotes, insects, and mammals has opened new avenues to construct chemically inducible promoters that respond to signals normally not recognized by plants. This review describes results and applications of these two approaches.
-
-
-
REGULATION OF FATTY ACID SYNTHESIS
Vol. 48 (1997), pp. 109–136More Less▪ AbstractAll plant cells produce fatty acids from acetyl-CoA by a common pathway localized in plastids. Although the biochemistry of this pathway is now well understood, much less is known about how plants control the very different amounts and types of lipids produced in different tissues. Thus, a central challenge for plant lipid research is to provide a molecular understanding of how plants regulate the major differences in lipid metabolism found, for example, in mesophyll, epidermal, or developing seed cells. Acetyl-CoA carboxylase (ACCase) is one control point that regulates rates of fatty acid synthesis. However, the biochemical modulators that act on ACCase and the factors that in turn control these modulators are poorly understood. In addition, little is known about how the expression of genes involved in fatty acid synthesis is controlled. This review evaluates current knowledge of regulation of plant fatty metabolism and attempts to identify the major unanswered questions.
-
-
-
MOLECULAR GENETIC ANALYSIS OF TRICHOME DEVELOPMENT IN ARABIDOPSIS
Vol. 48 (1997), pp. 137–163More Less▪ AbstractTwo basic questions in developmental biology are: How does a cell know when it should or should not differentiate, and once a cell is committed to differentiate, how is that process controlled? The first process regulates the arrangement or pattern of the various cell types, whereas the second makes cells functionally distinct. Together, these two processes define plant morphogenesis. Trichome development in Arabidopsis provides an excellent model to analyze these questions. First, trichome development in Arabidopsis is a relatively simple process. A single epidermal cell differentiates into a unicellular trichome. Second, this differentiation occurs in a nonrandom pattern on the plant surface. Finally, the process is amenable to genetic analysis because many mutations that affect trichome differentiation do not alter other aspects of plant development. Thus far, more than 20 genes affecting trichome development have been identified. This review examines the current state of our understanding of these genes.
-
-
-
FLUORESCENCE MICROSCOPY OF LIVING PLANT CELLS
Vol. 48 (1997), pp. 165–190More Less▪ AbstractSince its inception, light microscopy has shown the elegance and subtlety with which function is expressed in the form of the cells, tissues, and organs of the plant. Recently, light microscopy has seen a resurgence in use fueled by advances in microscope design and computer-based image analysis. The structural resolution afforded by static, fixed samples is being increasingly supplemented by approaches using fluorescent analogs and selective fluorescent indicators, which visualize the dynamic processes in living, functioning cells. This review describes some of these approaches and discusses how they are taking us a step closer to viewing the intricate complexity with which plants organize and regulate their functions down to the subcellular level.
-
-
-
PHLOEM UNLOADING: Sieve Element Unloading and Post-Sieve Element Transport
Vol. 48 (1997), pp. 191–222More Less▪ AbstractThe transport events from the sieve elements to the sites of utilization within the recipient sink cells contribute to phloem unloading. The phenomenon links sink metabolism and/or compartmentation with phloem transport to, and partitioning between, sinks. The nature of the linkage depends upon the cellular pathway and mechanism of unloading. The common unloading pathway is symplasmic, with an apoplasmic step at or beyond the sieve element boundary reserved for specialized situations. Plasmodesmal conductivity exerts the primary control over symplasmic transport that occurs by diffusion with bulk flow anticipated to be of increasing significance as import rate rises. In the case of an apoplasmic step, efflux across the plasma membranes of the vascular cells occurs by simple diffusion, whereas efflux from nonvascular cells of developing seeds is facilitated and, in some cases, energy coupled. Accumulation of sugars from the sink apoplasm universally occurs by a plasma membrane–bound sugar/proton symport mechanism.
-
-
-
OXYGEN DEFICIENCY AND ROOT METABOLISM: Injury and Acclimation Under Hypoxia and Anoxia
Vol. 48 (1997), pp. 223–250More Less▪ AbstractOxygen deficiency in the rooting zone occurs with poor drainage after rain or irrigation, causing depressed growth and yield of dryland species, in contrast with native wetland vegetation that tolerates such conditions. This review examines how roots are injured by O2 deficiency and how metabolism changes during acclimation to low concentrations of O2.
In the root apical meristem, cell survival is important for the future development; metabolic changes under anoxia help maintain cell survival by generating ATP anaerobically and minimizing the cytoplasmic acidosis associated with cell death. Behind the apex, where cells are fully expanded, ethylene-dependent death and lysis occurs under hypoxia to form continuous, gas-filled channels (aerenchyma) conveying O2 from the leaves. This selective sacrifice of cells may resemble programmed cell death and is distinct from cell death caused by anoxia. Evidence concerning alternative possible mechanisms of anoxia tolerance and avoidance is presented.
-
-
-
THE OXIDATIVE BURST IN PLANT DISEASE RESISTANCE
Vol. 48 (1997), pp. 251–275More Less▪ AbstractRapid generation of superoxide and accumulation of H2O2 is a characteristic early feature of the hypersensitive response following perception of pathogen avirulence signals. Emerging data indicate that the oxidative burst reflects activation of a membrane-bound NADPH oxidase closely resembling that operating in activated neutrophils. The oxidants are not only direct protective agents, but H2O2 also functions as a substrate for oxidative cross-linking in the cell wall, as a threshold trigger for hypersensitive cell death, and as a diffusible signal for induction of cellular protectant genes in surrounding cells. Activation of the oxidative burst is a central component of a highly amplified and integrated signal system, also involving salicylic acid and perturbations of cytosolic Ca2+, which underlies the expression of disease-resistance mechanisms.
-
-
-
THE ETHYLENE RESPONSE PATHWAY IN ARABIDOPSIS
Vol. 48 (1997), pp. 277–296More Less▪ AbstractThe simple gas ethylene influences a diverse array of plant growth and developmental processes including germination, senescence, cell elongation, and fruit ripening. This review focuses on recent molecular genetic studies, principally in Arabidopsis, in which components of the ethylene response pathway have been identified. The isolation and characterization of two of these genes has revealed that ethylene sensing involves a protein kinase cascade. One of these genes encodes a protein with similarity to the ubiquitous Raf family of Ser/Thr protein kinases. A second gene shows similarity to the prokaryotic two-component histidine kinases and most likely encodes an ethylene receptor. Additional elements involved in ethylene signaling have only been identified genetically. The characterization of these genes and mutants will be discussed.
-
-
-
PLANT TRANSFORMATION: Problems and Strategies for Practical Application
Vol. 48 (1997), pp. 297–326More Less▪ AbstractPlant transformation is now a core research tool in plant biology and a practical tool for cultivar improvement. There are verified methods for stable introduction of novel genes into the nuclear genomes of over 120 diverse plant species. This review examines the criteria to verify plant transformation; the biological and practical requirements for transformation systems; the integration of tissue culture, gene transfer, selection, and transgene expression strategies to achieve transformation in recalcitrant species; and other constraints to plant transformation including regulatory environment, public perceptions, intellectual property, and economics. Because the costs of screening populations showing diverse genetic changes can far exceed the costs of transformation, it is important to distinguish absolute and useful transformation efficiencies. The major technical challenge facing plant transformation biology is the development of methods and constructs to produce a high proportion of plants showing predictable transgene expression without collateral genetic damage. This will require answers to a series of biological and technical questions, some of which are defined.
-
-
-
CYANOBACTERIAL CIRCADIAN RHYTHMS
Vol. 48 (1997), pp. 327–354More Less▪ AbstractEvidence from a number of laboratories over the past 12 years has established that cyanobacteria, a group of photosynthetic eubacteria, possess a circadian pacemaker that controls metabolic and genetic functions. The cyanobacterial circadian clock exhibits the three intrinsic properties that have come to define the clocks of eukaryotes: The timekeeping mechanism controls rhythms that show a period of about 24 h in the absence of external signals, the phase of the rhythms can be reset by light/dark cues, and the period is relatively insensitive to temperature. The promise of cyanobacteria as simple models for elucidating the biological clock mechanism is being fulfilled, as mutants affected in period, rhythm generation, and rhythm amplitude, isolated through the use of real time reporters of gene expression, have implicated genes involved in these aspects of the clock.
-
-
-
BIOSYNTHESIS AND ACTION OF JASMONATES IN PLANTS
Vol. 48 (1997), pp. 355–381More Less▪ AbstractJasmonic acid and its derivatives can modulate aspects of fruit ripening, production of viable pollen, root growth, tendril coiling, and plant resistance to insects and pathogens. Jasmonate activates genes involved in pathogen and insect resistance, and genes encoding vegetative storage proteins, but represses genes encoding proteins involved in photosynthesis. Jasmonic acid is derived from linolenic acid, and most of the enzymes in the biosynthetic pathway have been extensively characterized. Modulation of lipoxygenase and allene oxide synthase gene expression in transgenic plants raises new questions about the compartmentation of the biosynthetic pathway and its regulation. The activation of jasmonic acid biosynthesis by cell wall elicitors, the peptide systemin, and other compounds will be related to the function of jasmonates in plants. Jasmonate modulates gene expression at the level of translation, RNA processing, and transcription. Promoter elements that mediate responses to jasmonate have been isolated. This review covers recent advances in our understanding of how jasmonate biosynthesis is regulated and relates this information to knowledge of jasmonate modulated gene expression.
-
-
-
PLANT IN VITRO TRANSCRIPTION SYSTEMS
Vol. 48 (1997), pp. 383–398More Less▪ AbstractIn vitro transcription systems provide a powerful tool for detailed analysis of transcription reactions including initiation, elongation, and termination. Despite problems inherent to plant cells, efforts have been made to develop plant in vitro transcription systems in the past decade. These efforts have finally culminated in the development of reliable in vitro systems from suspension-cell cultures of both monocot and dicot plants. These systems can be useful in elucidating the specific mechanisms involved in the process of plant transcription and thus can potentially open a new era of transcription studies in plants.
-
-
-
AQUAPORINS AND WATER PERMEABILITY OF PLANT MEMBRANES
Vol. 48 (1997), pp. 399–429More Less▪ AbstractThe mechanisms of plant membrane water permeability have remained elusive until the recent discovery in both vacuolar and plasma membranes of a class of water channel proteins named aquaporins. Similar to their animal counterparts, plant aquaporins have six membrane-spanning domains and belong to the MIP superfamily of transmembrane channel proteins. Their very high efficiency and selectivity in transporting water molecules have been mostly characterized using heterologous expression in Xenopus oocytes. However, techniques set up to measure the osmotic water permeability of plant membranes such as transcellular osmosis, pressure probe measurements, or stopped-flow spectrophotometry are now being used to analyze the function of plant aquaporins in their native membranes. Multiple mechanisms, at the transcriptional and posttranslational levels, control the expression and activity of the numerous aquaporin isoforms found in plants. These studies suggest a general role for aquaporins in regulating transmembrane water transport during the growth, development, and stress responses of plants. Future research will investigate the integrated function of aquaporins in long-distance water transport and cellular osmoregulation.
-
-
-
GIBBERELLIN BIOSYNTHESIS: Enzymes, Genes and Their Regulation
Peter Hedden, and Yuji KamiyaVol. 48 (1997), pp. 431–460More Less▪ AbstractThe recent impressive progress in research on gibberellin (GA) biosynthesis has resulted primarily from cloning of genes encoding biosynthetic enzymes and studies with GA-deficient and GA-insensitive mutants. Highlights include the cloning of ent-copalyl diphosphate synthase and ent-kaurene synthase (formally ent-kaurene synthases A and B) and the demonstration that the former is targeted to the plastid; the finding that the Dwarf-3 gene of maize encodes a cytochrome P450, although of unknown function; and the cloning of GA 20-oxidase and 3β-hydroxylase genes. The availability of cDNA and genomic clones for these enzymes is enabling the mechanisms by which GA concentrations are regulated by environmental and endogenous factors to be studied at the molecular level. For example, it has been shown that transcript levels for GA 20-oxidase and 3β-hydroxylase are subject to feedback regulation by GA action and, in the case of the GA 20-oxidase, are regulated by light. Also discussed is other new information, particularly from mutants, that has added to our understanding of the biosynthetic pathway, the enzymes, and their regulation and tissue localization.
-
-
-
POLLEN GERMINATION AND TUBE GROWTH
Vol. 48 (1997), pp. 461–491More Less▪ AbstractMany aspects of Angiosperm pollen germination and tube growth are discussed including mechanisms of dehydration and rehydration, in vitro germination, pollen coat compounds, the dynamic involvement of cytoskeletal elements (actin, microtubules), calcium ion fluxes, extracellular matrix elements (stylar arabinogalactan proteins), and control mechanisms of gene expression in dehydrating and germinating pollen. We focus on the recent developments in pollen biology that help us understand how the male gamete survives and accomplishes its successful delivery to the ovule of the sperm to effect sexual reproduction.
-
-
-
METABOLITE TRANSPORT ACROSS SYMBIOTIC MEMBRANES OF LEGUME NODULES
Vol. 48 (1997), pp. 493–523More Less▪ AbstractInfection of legume roots or stems with soil bacteria of the Rhizobiaceae results in the formation of nodules that become symbiotic nitrogen-fixing organs. Within the infected cells of these nodules, bacteria are enveloped in a membrane of plant origin, called the peribacteroid membrane (PBM), and divide and differentiate to form nitrogen-fixing bacteroids. The organelle-like structure comprised of PBM and bacteroids is termed the symbiosome, and is the basic nitrogen-fixing unit of the nodule. The major exchange of nutrients between the symbiotic partners is reduced carbon from the plant, to fuel nitrogenase activity in the bacteroid, and fixed nitrogen from the bacteroid, which is assimilated in the plant cytoplasm. However, many other metabolites are also exchanged. The metabolic interaction between the plant and the bacteroids is regulated by a series of transporters and channels on the PBM and the bacteroid membrane, and these form the focus of this review.
-
Previous Volumes
-
Volume 75 (2024)
-
Volume 74 (2023)
-
Volume 73 (2022)
-
Volume 72 (2021)
-
Volume 71 (2020)
-
Volume 70 (2019)
-
Volume 69 (2018)
-
Volume 68 (2017)
-
Volume 67 (2016)
-
Volume 66 (2015)
-
Volume 65 (2014)
-
Volume 64 (2013)
-
Volume 63 (2012)
-
Volume 62 (2011)
-
Volume 61 (2010)
-
Volume 60 (2009)
-
Volume 59 (2008)
-
Volume 58 (2007)
-
Volume 57 (2006)
-
Volume 56 (2005)
-
Volume 55 (2004)
-
Volume 54 (2003)
-
Volume 53 (2002)
-
Volume 52 (2001)
-
Volume 51 (2000)
-
Volume 50 (1999)
-
Volume 49 (1998)
-
Volume 48 (1997)
-
Volume 47 (1996)
-
Volume 46 (1995)
-
Volume 45 (1994)
-
Volume 44 (1993)
-
Volume 43 (1992)
-
Volume 42 (1991)
-
Volume 41 (1990)
-
Volume 40 (1989)
-
Volume 39 (1988)
-
Volume 38 (1987)
-
Volume 37 (1986)
-
Volume 36 (1985)
-
Volume 35 (1984)
-
Volume 34 (1983)
-
Volume 33 (1982)
-
Volume 32 (1981)
-
Volume 31 (1980)
-
Volume 30 (1979)
-
Volume 29 (1978)
-
Volume 28 (1977)
-
Volume 27 (1976)
-
Volume 26 (1975)
-
Volume 25 (1974)
-
Volume 24 (1973)
-
Volume 23 (1972)
-
Volume 22 (1971)
-
Volume 21 (1970)
-
Volume 20 (1969)
-
Volume 19 (1968)
-
Volume 18 (1967)
-
Volume 17 (1966)
-
Volume 16 (1965)
-
Volume 15 (1964)
-
Volume 14 (1963)
-
Volume 13 (1962)
-
Volume 12 (1961)
-
Volume 11 (1960)
-
Volume 10 (1959)
-
Volume 9 (1958)
-
Volume 8 (1957)
-
Volume 7 (1956)
-
Volume 6 (1955)
-
Volume 5 (1954)
-
Volume 4 (1953)
-
Volume 3 (1952)
-
Volume 2 (1951)
-
Volume 1 (1950)
-
Volume 0 (1932)