1,721,075 research outputs found
Signaling LTPs. A new plant LTPs sub-family?
No full textNumerous plant non specific Lipid Transfer Protein (nsLTPs) have been characterized for their antimicrobial activity, suggesting for these proteins a direct role in the protection against pathogenic microorganisms. Another group of LTPs seems to be involved in structural events in the extracellular matrix through binding and transport of hydrophobic molecules. More recently, some LTPs putatively involved in the symbiotic interaction between legumes and rhizobia have been identified. We investigated the role of MtN5, a LTP from Medicago truncatula, which is specifically expressed in the roots and induced by both Sinorhizobium meliloti and a root pathogenic fungus. Once the symbiosis has been established, MtN5 is preferentially accumulated in the root nodule. The suppression of MtN5 transcript, obtained by means of an RNAi approach, resulted in a reduced nodulation, whereas its overexpression led to an increased number of nodules produced by S. meliloti. These observations demonstrated that MtN5 is required for an efficient nodulation. On the base of the amino acid sequence, MtN5 has been included in the nsLTP-like sub-family, together with Arabidopsis thaliana DIR1, a protein playing a role in SAR signaling. The putative role(s) for this LTP in the symbiotic association are discussed in the present commentary. MtN5, together with DIR1 and other new LTPs, are proposed to form a new LTP subfamily involved in lipid signalling
Phosphorus deficiency changes carbon isotope fractionation and triggers exudate reacquisition in tomato plants
Full text linkPlant roots are able to exude vast amounts of metabolites into the rhizosphere in response to phosphorus (P) deficiency. Causing noteworthy costs in terms of energy and carbon (C) for the plants. Therefore, it is suggested that exudates reacquisition by roots could represent an energy saving strategy of plants. This study aimed at investigating the effect of P deficiency on the ability of hydroponically grown tomato plants to re-acquire specific compounds generally present in root exudates by using 13C-labelled molecules. Results showed that P deficient tomato plants were able to take up citrate (+ 37%) and malate (+ 37%), particularly when compared to controls. While glycine (+ 42%) and fructose (+ 49%) uptake was enhanced in P shortage, glucose acquisition was not affected by the nutritional status. Unexpectedly, results also showed that P deficiency leads to a 13C enrichment in both tomato roots and shoots over time (shoots—+ 2.66‰, roots—+ 2.64‰, compared to control plants), probably due to stomata closure triggered by P deficiency. These findings highlight that tomato plants are able to take up a wide range of metabolites belonging to root exudates, thus maximizing C trade off. This trait is particularly evident when plants grew in P deficiency. © 2020, The Author(s)
MEDICAGO TRUNCATULA ROOTS OVEREXPRESSING THE NSLTP N5 DISPLAY MODIFICATIONS IN THE LIPID PROFILE AND CHANGES IN THE EXPRESSION OF GENES INVOLVED IN LIPID METABOLISM AFTER SINORHIZOBIUM MELILOTI INFECTION
No full textTo shed light on the of MtN5 during early symbiotic events, we investigated the metabolic pathways for lipid production associated with the MtN5overespression. We carried out a comparative transcriptomic analysis of MtN5overexpressing (MtN5ox) and wild type roots after 72h of Sinorhizobium meliloti inoculation; in the same experimental conditions, we assayed the effects of MtN5 overexpression on the root lipid profile. In MtN5ox roots, we identified a quite relevant number of differential expressed genes involved in lipid transport and metabolism. The major changes were detected in genes implicated in phopholipid signalling pathways such as myo-inositol 1-phosphate synthases, phosphatidylinositolspecific phospholipase, phosphatidylinositol kinases, phosphatidylinositol transfer protein, inositol mono-phosphatase. All these transcripts were down-regulated in inoculated MtN5ox roots. Interestingly we demonstrated that MtN5 functioning is dependent on phospholipase D but not on phospholipase C activity (Pii et al., 2012). The analysis of the root lipid fraction revealed that MtN5 overexpressing roots displayed a general increase in the lipid content, that was especially relevant for galactolipids that are component of plastid and symbiosome membranes
Advances in viticulture via smart phenotyping: current progress and future directions in tackling soil copper accumulation
Full text linkModern viticulture faces significant challenges including climate change and increasing crop diseases, necessitating sustainable solutions to reduce fungicide use and mitigate soil health risks, particularly from copper accumulation. Advances in plant phenomics are essential for evaluating and tracking phenotypic traits under environmental stress, aiding in selecting resilient vine varieties. However, current methods are limited, hindering effective integration with genomic data for breeding purposes. Remote sensing technologies provide efficient, non-destructive methods for measuring biophysical and biochemical traits of plants, offering detailed insights into their physiological and nutritional state, surpassing traditional methods. Smart phenotyping is essential for selecting crop varieties with desired traits, such as pathogen-resilient vine varieties, tolerant to altered soil fertility including copper toxicity. Identifying plants with typical copper toxicity symptoms under high soil copper levels is straightforward, but it becomes complex with supra-optimal, already toxic, copper levels common in vineyard soils. This can induce multiple stress responses and interferes with nutrient acquisition, leading to ambiguous visual symptoms. Characterizing resilience to copper toxicity in vine plants via smart phenotyping is feasible by relating smart data with physiological assessments, supported by trained professionals who can identify primary stressors. However, complexities increase with more data sources and uncertainties in symptom interpretations. This suggests that artificial intelligence could be valuable in enhancing decision support in viticulture. While smart technologies, powered by artificial intelligence, provide significant benefits in evaluating traits and response times, the uncertainties in interpreting complex symptoms (e.g., copper toxicity) still highlight the need for human oversight in making final decisions
Fruit improvement using intragenesis and artificial microRNA
No full textGenetic engineering methods based on the use of transgenes have been successfully adopted to improve crops. A novel all-native DNA gene technology consists of the creation of intragenic constructs by isolating genetic elements from a crop, rearranging them in vitro, and inserting them back into the plant. The ever-increasing genomic information and the elucidation of the molecular mechanisms that control fruit development could be exploited to confer the desired fruit phenotypes using endogenous DNA. The spatial/temporal regulation of genes can be modified by using appropriate endogenous regulatory elements, such as fruit-specific promoters. In addition, intragenic silencing can be employed to downregulate fruit-related genes. Here, we describe the available tools for intragenic manipulation of early phases of fleshy fruit initiation
The characterization of the adaptive responses of durum wheat to different Fe availability highlights an optimum Fe requirement threshold
No full textPlant mechanisms responding to iron (Fe) deficiency have been widely described; it is well known that Strategy II plants, as durum wheat, cope with this stress by increasing both the synthesis and secretion of phytosiderophores (PS). The important contribution of the sulfate assimilatory pathway has been also demonstrated to improve Fe use efficiency in several grasses, such as maize, barley and wheat, most likely because PS are produced from nicotianamine, whose precursor is methionine. Here, the physiological response of durum wheat (T. durum L.) plants - in terms of plant ionome, PS release, thiols content and S pathway-related enzymes – was investigated by gradually decreasing Fe availability that allowed the identification of three specific limit Fe concentrations: 75 μM, 25 μM and 0 μM Fe, i.e. the complete Fe deprivation. At each limit, plants begin to induce different and specific adaptive responses to improve Fe acquisition or to reduce the damage resulting from limited Fe availability. The identification of the Fe availability level below which durum wheat plants start an expensive metabolic reorganization of S and several other elements, could be of benefit not only for an effective cultivation of the crop but also for the grain quality. © 2016 Elsevier Masson SA
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
Does MtN5 play a double role in root responses to symbiontic and pathogenic microorganisms?
Full text linkMtN5, a new Lipid Transfer Protein, has been identified in nodulated roots of Medicago truncatula andpreliminarily classified as early nodulin, which is expressed in response to rhizobial symbiosis. Wehave shown that the recombinant MtN5 exerts antifungal and antimicrobial activity in vitro againstFusarium semitectum and Rhizobium leguminosarum, respectively. In vivo, the fungal infection leadsto the expression of MtN5 in the whole root apparatus of M. truncatula plants, whereas the inoculationwith rhizobia induces an early and nodule-specific expression of the protein, that is also maintained inmature nodules. These two different expression patterns suggest a putative double role for MtN5, whichcould be involved both in a general response mechanism against fungi and in sensing or controlling theinfection of the symbiont. This last hypothesis is supported by the observation that M.truncatula rootstransformed with an hairpin construct aiming to silence endogenous MtN5, are impaired in noduleformation respect to control roots. Therefore, MtN5 is hereby proposed as a novel, multifunctionalprotein taking part in the symbiotic process
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