654 research outputs found
The maize PIN gene family of auxin transporters
No full textAuxin is a key regulator of plant development and its differential distribution in plant tissues, established by a polar cell to cell transport, can trigger a wide range of developmental processes. A few members of the two families of auxin efflux transport proteins, PIN-formed (PIN and P-glycoprotein (ABCB/PGP, have so far been characterized in maize. Nine new Zea mays auxin efflux carriers PIN family members and two maize PIN-like genes have now been identified. Four members of PIN1 (named ZmPIN1a-d cluster, one gene homologous to AtPIN2 (ZmPIN2, three orthologs of PIN5 (ZmPIN5a-c, one gene paired with AtPIN8 (ZmPIN8, and three monocot-specific PINs (ZmPIN9, ZmPIN10a, and ZmPIN10b were cloned and the phylogenetic relationships between early-land plants, monocots, and eudicots PIN proteins investigated, including the new maize PIN proteins. Tissue-specific expression patterns of the 12 maize PIN genes, 2 PIN-like genes and ZmABCB1, an ABCB auxin efflux carrier, were analyzed together with protein localization and auxin accumulation patterns in normal conditions and in response to drug applications. ZmPIN gene transcripts have overlapping expression domains in the root apex, during male and female inflorescence differentiation and kernel development. However, some PIN family members have specific tissue localization: ZmPIN1d transcript marks the L1 layer of the shoot apical meristem and inflorescence meristem during the flowering transition and the monocot-specific ZmPIN9 is expressed in the root endodermis and pericycle. The phylogenetic and gene structure analyses together with the expression pattern of the ZmPIN gene family indicate that subfunctionalization of some maize PINs can be associated to the differentiation and development of monocot-specific organs and tissues and might have occurred after the divergence between dicots and monocots. © 2012 Forestan, Farinati and Varotto
Insights into G1/S transition in plant
No full textThe G1/S transition generally represents the
principal point of commitment to cell division. Many of
the components of the cell cycle core machinery regulating
the G1/S transition in plants have been recently identified.
Although plant regulators of the G1/S transition display
structural and biochemical homologies with their animal
counterparts, their functions in integrating environmental
stimuli and the developmental program within cell cycle
progression are often plant-specific. In this review, recent
progress in understanding the role of plant G1/S transition
regulators is presented. Emerging evidence concerning
the mechanisms ofG1/S control in response to factors
triggering the cell cycle and the integration of these
mechanisms with plant development is also discussed
Current perspectives on the hormonal control of seed development in Arabidopsis and maize: a focus on auxin
No full textThe seed represents the unit of reproduction of flowering plants, capable of developing into another plant, and to ensure the survival of the species under unfavorable environmental conditions. It is composed of three compartments: seed coat, endosperm and embryo. Proper seed development depends on the coordination of the processes that lead to seed compartments differentiation, development and maturation. The coordination of these processes is based on the constant transmission/perception of signals by the three compartments. Phytohormones constitute one of these signals; gradients of hormones are generated in the different seed compartments, and their ratios comprise the signals that induce/inhibit particular processes in seed development. Among the hormones, auxin seems to exert a central role, as it is the only one in maintaining high levels of accumulation from fertilization to seed maturation. The gradient of auxin generated by its PIN carriers affects several processes of seed development, including pattern formation, cell division and expansion. Despite the high degree of conservation in the regulatory mechanisms that lead to seed development within the Spermatophytes, remarkable differences exist during seed maturation between Monocots and Eudicots species. For instance, in Monocots the endosperm persists until maturation, and constitutes an important compartment for nutrients storage, while in Eudicots it is reduced to a single cell layer, as the expanding embryo gradually replaces it during the maturation. This review provides an overview of the current knowledge on hormonal control of seed development, by considering the data available in two model plants: Arabidopsis thaliana, for Eudicots and Zea mays L., for Monocots. We will emphasize the control exerted by auxin on the correct progress of seed development comparing, when possible, the two species. © 2014 Locascio, Roig-Villanova, Bernardi and Varotto
ZmPIN1-mediated auxin transport is related to cellular differentiation during maize embryogenesis and endosperm development.
No full textTo study the influence of PINFORMED1 (PIN1)-mediated auxin transport during embryogenesis and endosperm development in monocots, the expression pattern of the three identified ZmPIN1 genes was determined at the transcript level. Localization of the corresponding proteins was also analyzed during maize (Zea mays) kernel development. An anti-indole-3-acetic acid (IAA) monoclonal antibody was used to visualize IAA distribution and correlate the direction of auxin active transport, mediated by ZmPIN1 proteins, with the actual amount of auxin present in maize kernels at different developmental stages. ZmPIN1 genes are expressed in the endosperm soon after double fertilization occurs; however, unlike other tissues, the ZmPIN1 proteins were never polarly localized in the plasma membrane of endosperm cells. ZmPIN1 transcripts and proteins also colocalize in developing embryos, and the ZmPIN1 proteins are polarly localized in the embryo cell plasma membrane from the first developmental stages, indicating the existence of ZmPIN1-mediated auxin fluxes. Auxin distribution visualization indicates that the aleurone, the basal endosperm transfer layer, and the embryo-surrounding region accumulate free auxin, which also has a maximum in the kernel maternal chalaza. During embryogenesis, polar auxin transport always correlates with the differentiation of embryo tissues and the definition of the embryo organs. On the basis of these reports and of the observations on tissue differentiation and IAA distribution in defective endosperm-B18 mutant and in N-1-naphthylphthalamic acid-treated kernels, a model for ZmPIN1-mediated transport of auxin and the related auxin fluxes during maize kernel development is proposed. Common features between this model and the model previously proposed for Arabidopsis (Arabidopsis thaliana) are discussed
UNDERSTANDING EPIALLELES FORMATION IN RESPONSE TO ENVIRONMENTAL CUES AND THEIR HERITABILITY IN PLANTS
No full textEpigenetics is defined as the study of heritable
traits that do not depend on the primary DNA sequence.
The discovery of epigenetic mechanisms acting
on chromatin to regulate global gene expression has revealed
how heritable variation need not be sequencebased.
Particularly, environmental factors can induce novel
variation through the activation of specific epigenetic
mechanisms that determine mutations of spatial and temporal
pattern of gene expression. The carriers of epigenetic
information are identified in DNA methylation, histone
tails post-translation modifications and histone variants.
Specific combinations of these marks can influence
chromatin structure that in turn affects transcription and
genome stability. The environment can induce various
types of epigenetic changes leading to alternative gene
expression patterns, which can either be restricted to somatic
and vegetative tissues or propagated through mitotic
cell divisions. Of particular interest is the distinction between
transient and stable changes in epigenetic marks
and the formation and maintenance of epialles. Epigenetic
alleles or epialleles show different distribution of epigenetic
marks in their sequence and can exhibit distinct
phenotypes. The search for natural occurring epialles and
the understanding of the mechanisms leading to their formation
and maintenance, particularly in response to environmental
cues, is a great challenge for the future
The Role of PIN Auxin Efflux Carriers in Polar Auxin Transport and Accumulation and Their Effect on Shaping Maize Development
No full textn plants, proper seed development and the continuing post-embryonic organogenesis both require that different cell types are correctly differentiated in response to internal and external stimuli. Among internal stimuli, plant hormones and particularly auxin and its polar transport (PAT) have been shown to regulate a multitude of plant physiological processes during vegetative and reproductive development. Although our current auxin knowledge is almost based on the results from researches on the eudicot Arabidopsis thaliana, during the last few years, many studies tried to transfer this knowledge from model to crop species, maize in particular. Applications of auxin transport inhibitors, mutant characterization, and molecular and cell biology approaches, facilitated by the sequencing of the maize genome, allowed the identification of genes involved in auxin metabolism, signaling, and particularly in polar auxin transport. PIN auxin efflux carriers have been shown to play an essential role in regulating PAT during both seed and post-embryonic development in maize. In this review, we provide a summary of the recent findings on PIN-mediated polar auxin transport during maize development. Similarities and differences between maize and Arabidopsis are analyzed and discussed, also considering that their different plant architecture depends on the differentiation of structures whose development is controlled by auxins
Characterization of AtMYB59 transcription factor
No full textanalysis of a transcription factor induced by cadmium and affecting plant developmen
Detecting 5G Signal Jammers with Autoencoders Based on Loose Observations
No full textFifth-generation (5G) networks are prone to jamming attacks, which are particularly dangerous in mission-critical applications such as factory automation. In this paper, we present a simple method to detect jamming attacks with machine learning techniques operating on in-phase and quadrature (IQ) modulated signals. In particular, a convolutional autoencoder (CAE) learns the structure of the clean signal to distinguish it from jammed signals in real time. This approach requires only a loose synchronization to the OFDM symbol, while equalization and decoding are not necessary. Despite its simplicity, our technique has shown high detection rates in experiments on a 5G testbed
Auxin Immunolocalization in Plant Tissues
No full textThe major naturally occurring auxin, indol-3 acetic acid (IAA), coordinates many growth and differentiation processes by modulating gene expression during plant development. The sites of IAA biosynthesis and its polar transport (PAT) routes determine auxin accumulation and distribution during growth. From many studies on the model plant Arabidopsis thaliana over the last years, it has become evident that the expression and sub-cellular localization of multiple transport proteins are required to initiate and maintain directional auxin fl ows within plant organs and tissues, creating the auxin concentration gradients that regulate plant development. For this reason, the understanding of auxin dependent pattern formation also relies on the possibility to directly visualize auxin concentration and distribution in the tissues. The production and isolation of antibodies highly speci fi c for IAA provide the means to detect and localize free IAA in different plant species during tissues differentiation and organ development. The immunolocalization protocol presented here uses a monoclonal anti-IAA speci fi c antibody that can be used to visualize auxin accumulation in different organs and tissues during plant development. We successfully used this protocol to determine IAA maxima during kernel and in fl orescence development in maize, highlighting also alterations in auxin accumulation patterns in a mutant with reduced auxin accumulation capacity and in plants treated with an inhibitor of auxin transport. © Springer Science+Business Media New York 2013
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