1,720,999 research outputs found
Overexpression of isoprene synthase affects ABA-and drought-related gene expression and enhances tolerance to abiotic stress
Full text linkIsoprene is the most abundant single biogenic volatile compound emitted by plants. Despite the relevance of this molecule to plant abiotic resistance and its impact on global atmospheric chemistry, little is known about the details of its mechanism of action. Here, we characterized through both physiological and molecular methods the mechanisms of action of isoprene using model transgenic arabidopsis lines overexpressing a monocot isoprene synthase gene. Our results demonstrated the effect that isoprene had on ABA signaling at different tissue-specific, spatial, and temporal scales. In particular, we found that isoprene enhanced stomatal sensitivity to ABA through upregulation of RD29B signaling gene. By contrast, isoprene decreased sensitivity to ABA in germinating seeds and roots, suggesting tissue-specific mechanisms of action. In leaves, isoprene caused the downregulation of COR15A and P5CS genes, suggesting that the enhanced tolerance to water-deprivation stress observed in isoprene-emitting plants may be mediated chiefly by an enhanced membrane integrity and tolerance to osmotic stress
Climacteric ripening of apple fruit is regulated by transcriptional circuits stimulated by cross-talks between ethylene and auxin
No full textApple is a fleshy fruit distinguished by a climacteric type of ripening, since most of the relevant physiological changes are triggered and governed by the action of ethylene. After its production, this hormone is perceived by a series of receptors to regulate, through a signaling cascade, downstream ethylene related genes. The possibility to control the effect of ethylene opened new horizons to the improvement of the postharvest fruit quality. To this end, 1-methylcyclopropene (1-MCP), an ethylene antagonist, is routinely used to modulate the ripening progression increasing storage life. In a recent work published in The Plant Journal, the whole transcriptome variation throughout fruit development and ripening, with the adjunct comparison between normal and impaired postharvest ripening, has been illustrated. In particular, besides the expected downregulation of ethylene-regulated genes, we shed light on a regulatory circuit leading to de-repressing the expression of a specific set of genes following 1-MCP treatment, such as AUX/IAA, NAC and MADS. These findings suggested the existence of a possible ethylene/auxin cross-talk in apple, regulated by a transcriptional circuit stimulated by the interference at the ethylene receptor leve
Overexpression of isoprene synthase affects ABA- and drought-related gene expression and enhances tolerance to abiotic stress
Full text linkIsoprene is the most abundant single biogenic volatile compound emitted by plants.
Despite the relevance of this molecule to plant abiotic resistance and its impact on global atmospheric
chemistry, little is known about the details of its mechanism of action. Here, we characterized
through both physiological and molecular methods the mechanisms of action of isoprene using
model transgenic arabidopsis lines overexpressing a monocot isoprene synthase gene. Our results
demonstrated the eect that isoprene had on ABA signaling at dierent tissue-specific, spatial,
and temporal scales. In particular, we found that isoprene enhanced stomatal sensitivity to ABA
through upregulation of RD29B signaling gene. By contrast, isoprene decreased sensitivity to ABA in
germinating seeds and roots, suggesting tissue-specific mechanisms of action. In leaves, isoprene
caused the downregulation of COR15A and P5CS genes, suggesting that the enhanced tolerance
to water-deprivation stress observed in isoprene-emitting plants may be mediated chiefly by an
enhanced membrane integrity and tolerance to osmotic stress
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The interference of the ethylene perception machinery leads to a re-programming of the fruit quality-related transcriptome and induces a cross-talk circuit with auxin in apple
No full textEthylene is a gaseous plant hormone playing a myriad of roles during several processes taking place during the entire life-cycle of a plant. Amongst all, the hormone ethylene is considered to be the master regulator of climacteric fruit ripening, triggering and coordinating important physiological pathways leading, in the end, to the development of properties and features essential for the definition of fruit quality. In modern horticulture, however, excessive ripening can lead to serious general fruit decay and loss. To preserve the quality features acquired at the end of ripening, simultaneously preventing quality drop-off, the postharvest management can to date benefit of several strategies, among which the most efficient is the control of ethylene through exogenous application of a competitor known as 1-methylcyclopropene (1-MCP). The transcriptional re-programming coded by this molecule was investigated through the fruit development and ripening with two microarray platforms, a candidate gene based and a whole genome array, respectively. In parallel to the expected repressing effect, 1-MCP can also stimulate an equal dose of genes, mainly involved in the photosynthetic process, transcriptional regulation and hormones. In the end, the effect of ethylene has been also investigated into a more general fruit quality context. Although the inhibition of this hormone has an unquestionable effect on postharvest and fruit loss control, it may also harm fruit quality, diminishing the aromatic bouquet produced by the fruit
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