1,720,985 research outputs found
The maize PIN gene family of auxin transporters
Full text linkAuxin 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
Arabidopsis halleri response to heavy metals and rhizosphere microorganisms: a proteomic approach
No full textHow plants cope with Cadmium: staking all on metabolism and gene expression.
No full textEnvironmental pollution is one of the major problems for human health. Toxic heavy metals are normally present as soil constituents or can also be spread out in the environment by human activity and agricultural techniques. Soil contamination by heavy metals as cadmium, highlights two main aspects: on one side they interfere with the life cycle of plants and therefore reduce crop yields, and on the other hand, once adsorbed and accumulated into the plant tissues, they enter the food chain poisoning animals and humans. Considering this point of view, understanding the mechanism by which plants handle heavy metal exposure, in particular cadmium stress, is a primary goal of plant-biotechnology research or plant breeders whose aim is to create plants that are able to recover high amounts of heavy metals, which can be used for phytoremediation, or identify crop varieties that do not accumulate toxic metal in grains or fruits. In this review we focus on the main symptoms of cadmium toxicity both on root apparatus and shoots. We elucidate the mechanisms that plants activate to prevent absorption or to detoxify toxic metal ions, such as synthesis of phytochelatins, metallothioneins and enzymes involved in stress response. Finally we consider new plant-biotechnology applications that can be applied for phytoremediatio
De novo identification of sRNA loci and non-coding RNAs by high-throughput sequencing
No full textNon-coding RNA transcripts, such as long non-coding RNAs, miRNAs, siRNAs, and transposon-originating transcripts, are involved in the regulation of RNA stability, protein translation, and/or the modulation of chromatin states. RNA-Seq can be used to catalog this diversity of novel transcripts and a joint analysis of these transcriptomic data can provide useful insights into epigenetic regulation of dynamic responses such as the stress response, which may not be deciphered from individual analysis of single transcript categories. Here, we present a protocol that allows the identification and analysis of small RNAs and long non-coding RNAs, together with the comparison of these species between different sample types
Epigenetic mechanisms controlling peach bud dormancy and its release: preliminary results
No full textBud dormancy regulation represents a fundamental process for perennial plant survival. Recent findings highlight the importance of epigenetic regulation of dormancy events, and more specifically of chromatin regulation of DAM-related genes in flower buds of Rosaceae. The main goal of this work is to improve our knowledge on the genetic and epigenetic mechanisms during the dormancy and its release in peach buds. During the dormancy, buds were sampled from peach trees (P. persica [L.] Batsch) ‘Fantasia’ and SR mutant. To investigate bud dormancy at genetic level we analyzed the expression profile of DAM genes in both genotypes to identify the most informative time points in which to perform an extensive analysis of transcriptome by RNA-Seq. At the beginning of the dormancy the expression of DAM4 and DAM6 increases and concurrently the fulfillment of chilling requirement the abundance of their corresponding mRNAs sharply decreased in both vegetative and flower buds. The transcriptome analysis showed a total of 2.470 unique DEGs by comparing the SR and FAN buds, among which genes involved in histone (H3) methylation are present
EPIGENETIC REGULATION OF ENDOREDUPLICATION PROCESS: A KEY ROLE FOR A CORRECT PEACH FRUIT SIZE AND RIPENING TIMING
Full text linkAmong the several phenotypic traits which characterize the fruit quality, the fruit dimension is
one of the major aspects evaluated in the present worldwide socio-economical context, since it
could be directly related to food and human nutrition supply. From a molecular point of view the
fruit growth and the related fruit size are influenced by different biological processes, including
endoreduplication events in pericarp tissue. In plants, endoreduplication can occur in different cell
types, putatively related with peculiar functions. In fruit crops, endoreduplication have been largely
studied during fruit growth from an ultrastructural and cytologic point of view, while the molecular
and genetic basis of this process are still poorly understood. The genetic control of
endoreduplication during fruit growth is functional to a better understanding of regulatory
mechanisms governing fruit size and ripening timing.
In this research we focused our attention on endoreduplication events occurring in different
peach cvs (Prunus persica L. Batsch) characterized by different size and harvest time, that are
Springcrest (early ripening) and Fantasia (late ripening). In addition, we took advantage of a peach
mutation identified in a free-pollinated population of Fantasia named slow ripening (SR). SR
phenotype is associated to an altered transcriptional regulation of genes involved in mesocarp
identity, and shows a reduction of final fruit size together to the loss of fundamental ripening traits.
In the three cultivars, genes activating endoreduplication (orthologous to Arabidopsis WEE1 and
KRP3) are more expressed in Fantasia in comparison to Springcrest and SR. These transcription
profiles are consistent with flow cytometry data that pointed out an altered endoreduplication level
in Springcrest and SR. In parallel, the involvement of specific epigenetic marks (H3K4me3,
H3K27me3 and H3K9ac) were analyzed at the target gene loci with the goal to link fruit
endoreduplication events to epigenetic control
Effects of Rhizosphere Bacteria on Shoot Proteome and Heavy Metal Accumulation in the Hyperaccumulator Arabidopsis halleri.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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