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The Evolving Telomeres

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198818 Year: Pages: 74 DOI: 10.3389/978-2-88919-881-8 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Genetics
Added to DOAB on : 2016-01-19 14:05:46
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What controls the different rates of evolution to give rise to conserved and divergent proteins and RNAs? How many trials until evolution can adapt to physiological changes? Every organism has arisen through multiple molecular changes, and the mechanisms that are employed (mutagenesis, recombination, transposition) have been an issue left to the elegant discipline of evolutionary biology. But behind the theory are realities that we have yet to ascertain: How does an evolving cell accommodate its requirements for both conserving its essential functions, while also providing a selective advantage? In this volume, we focus on the evolution of the eukaryotic telomere, the ribo-nuclear protein complex at the end of a linear chromosome. The telomere is an example of a single chromosomal element that must function to maintain genomic stability. The telomeres of all species must provide a means to avoid the attrition from semi-conservative DNA replication and a means of telomere elongation (the telomere replication problem). For example, telomerase is the most well-studied mechanism to circumvent telomere attrition by adding the short repeats that constitutes most telomeres. The telomere must also guard against the multiple activities that can act on an unprotected double strand break requiring a window (or checkpoint) to compensate for telomere sequence loss as well as protection against non-specific processes (the telomere protection problem). This volume describes a range of methodologies including mechanistic studies, phylogenetic comparisons and data-based theoretical approaches to study telomere evolution over a broad spectrum of organisms that includes plants, animals and fungi. In telomeres that are elongated by telomerases, different components have widely different rates of evolution. Telomerases evolved from roots in archaebacteria including splicing factors and LTR-transposition. At the conserved level, the telomere is a rebel among double strand breaks (DSBs) and has altered the function of the highly conserved proteins of the ATM pathway into an elegant means of protecting the chromosome end and maintaining telomere size homeostasis through a competition of positive and negative factors. This homeostasis, coupled with highly conserved capping proteins, is sufficient for protection. However, far more proteins are present at the telomere to provide additional species-specific functions. Do these proteins provide insight into how the cell allows for rapid change without self-destruction?

Transfer Cells

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194742 Year: Pages: 126 DOI: 10.3389/978-2-88919-474-2 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2016-03-10 08:14:33
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Transfer cells are anatomically specialized cells optimized to support high levels of nutrient transport in plants. These cells trans-differentiate from existing cell types by developing extensive and localized wall ingrowth labyrinths to amplify plasma membrane surface area which in turn supports high densities of membrane transporters. Unsurprisingly, therefore, transfer cells are found at key anatomical sites for nutrient acquisition, distribution and exchange. Transfer cells are involved in delivery of nutrients between generations and in the development of reproductive organs and also facilitate the exchange of nutrients that characterize symbiotic associations. Transfer cells occur across all taxonomic groups in higher plants and also in algae and fungi. Deposition of wall ingrowth-like structures are also seen in “syncytia” and “giant cells” which function as feeding sites for cyst and root-knot nematodes, respectively, following their infection of roots. Consequently, the formation of highly localized wall ingrowth structures in diverse cell types appears to be an ancient anatomical adaption to facilitate enhanced rates of apoplasmic transport of nutrients in plants. In some systems a role for transfer cells in the formation of an anti-pathogen protective barrier at these symplastic discontinuities has been inferred. Remarkably, the extent of cell wall ingrowth development at a particular site can show high plasticity, suggesting that transfer cell differentiation might be a dynamic process adapted to the transport requirements of each physiological condition. Recent studies exploiting different experimental systems to investigate transfer cell biology have identified signaling pathways inducing transfer cell development and genes/gene networks that define transfer cell identity and/or are involved in building the wall ingrowth labyrinths themselves. Further studies have defined the structure and composition of wall ingrowths in different systems, leading in many instances to the conclusion that this process may involve previously uncharacterized mechanisms for localized wall deposition in plants. Since transfer cells play important roles in plant development and productivity, the latter being relevant to crop yield, especially so in major agricultural species such as wheat, barley, soybean and maize, understanding the molecular and cellular events leading to wall ingrowth deposition holds exciting promise to develop new strategies to improve plant performance, a key imperative in addressing global food security. This Research Topic presents a timely and comprehensive treatise on transfer cell biology to help define critical questions for future research and thereby generating a deeper understanding of these fascinating and important cells in plant biology.

Versatile roles of organelle outer membranes in intracellular communication

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196043 Year: Pages: 166 DOI: 10.3389/978-2-88919-604-3 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Botany
Added to DOAB on : 2016-08-16 10:34:25
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This topic covers emerging knowledge about the properties and functions of the outer membranes of chloroplasts and mitochondria. These outer membranes house various processes necessary for efficient communication and thus integration of the organelles with and into their surroundings in the cytoplasm. Such processes include, but are not limited to, protein import, organelle division, organelle movement, metabolism, and metabolite/ion transport. Recent molecular genetic, biochemical and cell biological studies have revealed functions of various outer membrane proteins. These findings have helped address and generate diverse biological and evolutionary questions at molecular, cellular and whole organism levels. The topic should encourage contributions of scientists from various disciplines and thus would provide the field with opportunities to "think outside the box" and to develop potential collaborations. The topic is also aimed to stimulate interests of general audience in the outer membranes of chloroplasts and mitochondria.

Recent Advances in Flowering Time Control

Authors: --- --- --- --- et al.
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451159 Year: Pages: 255 DOI: 10.3389/978-2-88945-115-9 Language: English
Publisher: Frontiers Media SA
Subject: Genetics --- Botany --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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The onset of flowering is an important step during the lifetime of a flowering plant. During the past two decades, there has been enormous progress in our understanding of how internal and external (environmental) cues control the transition to reproductive growth in plants. Many flowering time regulators have been identified from the model plant Arabidopsis thaliana. Most of them are assembled in regulatory pathways, which converge to central integrators which trigger the transition of the vegetative into an inflorescence meristem. For crop cultivation, the time of flowering is of upmost importance, because it determines yield. Phenotypic variation for this trait is largely controlled by genes, which were often modified during domestication or crop improvement. Understanding the genetic basis of flowering time regulation offers new opportunities for selection in plant breeding and for genome editing and genetic modification of crop species.

Plant Organ Abscission: From Models to Crops

Authors: --- --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889453283 Year: Pages: 271 DOI: 10.3389/978-2-88945-328-3 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Botany
Added to DOAB on : 2018-02-27 16:16:45
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Plant organ abscission is a developmental process regulated by the environment, stress, pathogens and the physiological status of the plant. In particular, seed and fruit abscission play an important role in seed dispersion and plant reproductive success and are common domestication traits with important agronomic consequences for many crop species. Indeed, in natural populations, shedding of the seed or fruit at the correct time is essential for reproductive success, while for crop species the premature or lack of abscission may be either beneficial or detrimental to crop productivity. The use of model plants, in particular Arabidopsis and tomato, have led to major advances in our understanding of the molecular and cellular mechanisms underlying organ abscission, and now many workers pursue the translation of these advances to crop species. Organ abscission involves specialized cell layers called the abscission zone (AZ), where abscission signals are perceived and cell separation takes place for the organ to be shed. A general model for plant organ abscission includes (1) the differentiation of the AZ, (2) the acquisition of AZ cells to become competent to respond to various abscission signals, (3) response to signals and the activation of the molecular and cellular processes that lead to cell separation in the AZ and (4) the post-abscission events related to protection of exposed cells after the organ has been shed. While this simple four-phase framework is helpful to describe the abscission process, the exact mechanisms of each stage, the differences between organ types and amongst diverse species, and in response to different abscission inducing signals are far from elucidated. For an organ to be shed, AZ cells must transduce a multitude of both endogenous and exogenous signals that lead to transcriptional and cellular and ultimately cell wall modifications necessary for adjacent cells to separate. How these key processes have been adapted during evolution to allow for organ abscission to take place in different locations and under different conditions is unknown. The aim of the current collection of articles is to present and be able to compare recent results on our understanding of organ abscission from model and crop species, and to provide a basis to understand both the evolution of abscission in plants and the translation of advances with model plants for applications in crop species.

Inter-cellular Electrical Signals in Plant Adaptation and Communication

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889455218 Year: Pages: 120 DOI: 10.3389/978-2-88945-521-8 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Botany --- Physiology
Added to DOAB on : 2019-01-23 14:53:42
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Plants use the Sun's energy to synthesize the basic biomolecules that make up all the organic matter of all organisms of terrestrial ecosystems, including ourselves. Therefore, understanding their adaptive mechanisms to variations of environmental factors, both biotic and abiotic, is fundamental, and particularly relevant in the current context of rapid climate change. Some of the most important adaptive mechanisms of plants are the electrical and chemical signaling systems for the exchange of information between proximally and distally located cells. These signalling systems allow plants to dynamically coordinate the activities of all cells under a diversity of situations. In this Research Topic, we present eight articles that bring up new hypothesis and data to understand the mechanisms of systemic electrical signaling and the central role that it plays in adapting the whole plant to different stresses, as well as new findings on intracellular calcium and nitric oxide-based signaling pathways under stress, which could be extrapolated to non-plant research.

Regulation of Cell Fate Determination in Plants

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193240 Year: Pages: 84 DOI: 10.3389/978-2-88919-324-0 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2016-03-10 08:14:32
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Plants are made up of a large number of distinct cell types that originate from a single fertilized egg cell. How the diversity of cell types arise in appropriate places is one of the most fascinating and attractive research areas of plant biology. During the past several decades, due to the development of new molecular techniques and tools, advances in optical microscopy, and availability of whole genome information and mutants in the model plant Arabidopsis and other plants, great advances have been made in understanding the mechanisms involved in cell fate determination in plants. Multiple mechanisms are used to generate cellular diversity. Asymmetric cell division is one of the primary mechanisms. As an example, asymmetric cell division enables one stem cell to generate a stem cell daughter and a daughter with a distinct identity. Initially equivalent cells can also differentiate to generate different cell types. This mechanism has been clearly demonstrated in the formation of multiple cell types during epidermis development in the shoot and root. Cell fate determination is influenced by both intrinsic factors, i.e, developmental regulators, as well as extrinsic signals, i.e., environmental stimuli. By using model systems like stomata, trichome, root hair and shoot and root apical meristem cells, ligands, receptors and transcription factors have been found to regulate cell fate determination. However, the details of signaling cassettes responsible for cell fate determination remain largely unknown. Plants are made up of a large number of distinct cell types that originate from a single fertilized egg cell. How the diversity of cell types arise in appropriate places is one of the most fascinating and attractive research areas of plant biology. During the past several decades, due to the development of new molecular techniques and tools, advances in optical microscopy, and availability of whole genome information and mutants in the model plant Arabidopsis and other plants, great advances have been made in understanding the mechanisms involved in cell fate determination in plants. This research topic contains 12 collected articles, including 2 Opinion Articles, 5 Reviews, 4 Mini Reviews, and 1 Original Research Article. Hopefully, these articles will expand our understanding of the regulation of cell fate determination in plants.

Assembly of the Photosystem II Membrane-Protein Complex of Oxygenic Photosynthesis

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452330 Year: Pages: 315 DOI: 10.3389/978-2-88945-233-0 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2017-10-13 14:57:01
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Photosystem II is a 700-kDa membrane-protein super-complex responsible for the light-driven splitting of water in oxygenic photosynthesis. The photosystem is comprised of two 350-kDa complexes each made of 20 different polypeptides and over 80 co-factors. While there have been major advances in understanding the mature structure of this photosystem many key protein factors involved in the assembly of the complex do not appear in the holoenzyme. The mechanism for assembling this super-complex is a very active area of research with newly discovered assembly factors and subcomplexes requiring characterization. Additionally the ability to split water is inseparable from light-induced photodamage that arises from radicals and reactive O2 species generated by Photosystem II chemistry. Consequently, to sustain water splitting, a “self repair” cycle has evolved whereby damaged protein is removed and replaced so as to extend the working life of the complex. Understanding how the biogenesis and repair processes are coordinated is among several important questions that remain to be answered. Other questions include: how and when are the inorganic cofactors inserted during the assembly and repair processes and how are the subcomplexes protected from photodamage during assembly? Evidence has also been obtained for Photosystem II biogenesis centers in cyanobacteria but do these also exist in plants? Do the molecular mechanisms associated with Photosystem II assembly shed fresh light on the assembly of other major energy-transducing complexes such as Photosystem I or the cytochrome b6/f complex or indeed other respiratory complexes? The contributions to this Frontiers in Plant Science Research Topic are likely to reveal new details applicable to the assembly of a range of membrane-protein complexes, including aspects of self-assembly and solar energy conversion that may be applied to artificial photosynthetic systems. In addition, a deeper understanding of Photosystem II assembly — particularly in response to changing environmental conditions — will provide new knowledge underpinning photosynthetic yields which may contribute to improved food production and long-term food security.

Salinity Tolerance in Plants

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ISBN: 9783039210268 / 9783039210275 Year: Pages: 422 DOI: 10.3390/books978-3-03921-027-5 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology --- Biochemistry
Added to DOAB on : 2019-06-26 10:09:00
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Salt stress is one of the most damaging abiotic stresses because most crop plants are susceptible to salinity to different degrees. According to the FAO, about 800 million Has of land are affected by salinity worldwide. Unfortunately, this situation will worsen in the context of climate change, where there will be an overall increase in temperature and a decrease in average annual rainfall worldwide. This Special Issue presents different research works and reviews on the response of plants to salinity, focused from different points of view: physiological, biochemical, and molecular levels. Although an important part of the studies on the response to salinity have been carried out with Arabidopsis plants, the use of other species with agronomic interest is also notable, including woody plants. Most of the conducted studies in this Special Issue were focused on the identification and characterization of candidate genes for salt tolerance in higher plants. This identification would provide valuable information about the molecular and genetic mechanisms involved in the salt tolerance response, and it also supplies important resources to breeding programs for salt tolerance in plants.

Keywords

Arabidopsis --- Brassica napus --- ion homeostasis --- melatonin --- NaCl stress --- nitric oxide --- redox homeostasis --- Chlamydomonas reinhardtii --- bZIP transcription factors --- salt stress --- transcriptional regulation --- photosynthesis --- lipid accumulation --- Apocyni Veneti Folium --- salt stress --- multiple bioactive constituents --- physiological changes --- multivariate statistical analysis --- banana (Musa acuminata L.) --- ROP --- genome-wide identification --- abiotic stress --- salt stress --- MaROP5g --- rice --- genome-wide association study --- salt stress --- germination --- natural variation --- Chlamydomonas reinhardtii --- salt stress --- transcriptome analysis --- impairment of photosynthesis --- underpinnings of salt stress responses --- chlorophyll fluorescence --- J8-1 plum line --- mandelonitrile --- Prunus domestica --- redox signalling --- salicylic acid --- salt-stress --- soluble nutrients --- Arabidopsis thaliana --- VOZ --- transcription factor --- salt stress --- transcriptional activator --- chlorophyll fluorescence --- lipid peroxidation --- Na+ --- photosynthesis --- photosystem --- RNA binding protein --- nucleolin --- salt stress --- photosynthesis --- light saturation point --- booting stage --- transcriptome --- grapevine --- salt stress --- ROS detoxification --- phytohormone --- transcription factors --- Arabidopsis --- CDPK --- ion homeostasis --- NMT --- ROS --- salt stress --- antioxidant enzymes --- Arabidopsis thaliana --- ascorbate cycle --- hydrogen peroxide --- reactive oxygen species --- salinity --- SnRK2 --- RNA-seq --- DEUs --- flax --- NaCl stress --- EST-SSR --- Salt stress --- Oryza sativa --- proteomics --- iTRAQ quantification --- cell membrane injury --- root activity --- antioxidant systems --- ion homeostasis --- melatonin --- salt stress --- signal pathway --- SsMAX2 --- Sapium sebiferum --- drought, osmotic stress --- salt stress --- redox homeostasis --- strigolactones --- ABA --- TGase --- photosynthesis --- salt stress --- polyamines --- cucumber --- abiotic stresses --- high salinity --- HKT1 --- halophytes --- glycophytes --- poplars (Populus) --- salt tolerance --- molecular mechanisms --- SOS --- ROS --- Capsicum annuum L. --- CaDHN5 --- salt stress --- osmotic stress --- dehydrin --- Gossypium arboretum --- salt tolerance --- single nucleotide polymorphisms --- association mapping. --- n/a

Plant Innate Immunity 2.0

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ISBN: 9783038975809 Year: Pages: 386 DOI: 10.3390/books978-3-03897-581-6 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Biology --- Science (General)
Added to DOAB on : 2019-04-05 10:34:31
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Plants possess a rather complex and efficient immune system. During their evolutionary history, plants have developed various defense strategies in order to recognize and distinguishing between self and non-self, and face pathogens and animal pests. Accordingly, to study the plant innate immunity represents a new frontier in the plant pathology and crop protection fields. This book is structured in 6 sections. The first part introduces some basic and general aspects of the plant innate immunity and crop protection. Sections 2–5 focus on fungal and oomycete diseases (section 2), bacterial and phytoplasma diseases (section 3), virus diseases (section 4), and insect pests (section 5), with a number of case studies and plant–pathogen/pest interactions. The last section deals with plant disease detection and control. The book aims to highlight new trends in these relevant areas of plant sciences, providing a global perspective that is useful for future and innovative ideas.

Keywords

dieback --- disease management --- Lasiodiplodia theobromae --- mango --- pathogenicity --- Bromoviridae --- plant–virus interactions --- plant defense response --- Prune dwarf virus --- replication process --- systemic and local movement --- plant proteases --- plant immunity --- MTI --- ETI --- SAR --- ISR --- RNA silencing --- RTNLB --- Agrobacterium --- biotic stress responses --- calcium --- calcium signature --- calmodulin --- CMLs --- CDPKs --- plant immunity --- symbiosis --- cell wall --- cellulose synthase --- hypersensitive response --- pathogenesis related-protein 2 --- plant-virus interaction --- Potato virus Y --- ultrastructure --- aphid resistance --- Arabidopsis thaliana --- hydroperoxide lyase --- Macrosiphum euphorbiae --- Myzus persicae --- Solanum lycopersicum --- ?-3 fatty acid desaturase --- Arabidopsis --- azelaic acid --- glycerol-3-phosphate --- light dependent signalling --- methyl salicylate --- N-hydroxypipecolic acid --- pipecolic acid --- salicylic acid --- SAR signalling --- spectral distribution of light --- tobacco --- rice --- Chilo suppressalis --- mitogen-activated protein kinase 4 --- jasmonic acid --- salicylic acid --- ethylene --- herbivore-induced defense response --- downy mildew --- grapevine --- PRRs --- PTI --- VaHAESA --- bismerthiazol --- rice --- induced defense responses --- chemical elicitors --- Sogatella furcifera --- defense-related signaling pathways --- tomato gray mold --- tomato leaf mold --- Bacillus subtilis --- biological control --- Capsicum annuum --- Ralstonia solanacearum --- CaWRKY40b --- immunity --- negative regulator --- transcriptional modulation --- Capsicum annuum --- CaWRKY22 --- immunity --- Ralstonia Solanacearum --- WRKY networks --- metabolomics --- plant defence --- plant–microbe interactions --- priming --- pre-conditioning --- citrus decline disease --- Citrus sinensis --- Bakraee --- “Candidatus Liberibacter” --- “Candidatus Phytoplasma” --- microbiota --- innate immunity --- basal defense --- rice blast --- Magnaporthe oryzae --- proteomics --- iTRAQ --- candidate disease resistance gene --- disease resistance --- downy mildew --- garden impatiens --- leaf transcriptome --- New Guinea impatiens --- RNA-Seq --- polyphenol oxidase --- Camellia sinensis --- Ectropis obliqua --- wounding --- regurgitant --- rice --- OsGID1 --- gibberellin --- herbivore-induced plant defenses --- Nilaparvata lugens --- plant protection products --- agrochemicals --- sustainable crop protection --- food security

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