176 research outputs found
"The Fed's Real Reaction Function: Monetary Policy, Inflation, Unemployment, Inequality-and Presidential Politics"
Using a VAR model of the American economy from 1984 to 2003, we find that, contrary to official claims, the Federal Reserve does not target inflation or react to "inflation signals." Rather, the Fed reacts to the very "real" signal sent by unemployment, in a way that suggests that a baseless fear of full employment is a principal force behind monetary policy. Tests of variations in the workings of a Taylor Rule, using dummy variable regressions, on data going back to 1969 suggest that after 1983 the Federal Reserve largely ceased reacting to inflation or high unemployment, but continued to react when unemployment fell "too low." Further, we find that monetary policy (measured by the yield curve) has significant causal impact on pay inequality-a domain where the Fed refuses responsibility. Finally, we test whether Federal Reserve policy has exhibited a pattern of partisan bias in presidential election years, with results that suggest the presence of such bias, after controlling for the effects of inflation and unemployment.
The molecular control of tomato fruit quality traits: the trade off between visual attributes, shelf life and nutritional value
Tomato (Solanum lycopersicum) is an established model to study fleshy fruit development and ripening and is an important crop in terms of its economic and nutritional value. Tomato fruit quality is a function of metabolite content which is prone to physiological changes related to fruit development and ripening. It has been described some ripening tomato mutants, delayed fruit deterioration (DFD), non-ripening (NOR) and ripening-inhibitor (RIN) which substantially extend āshelf lifeā in tomato for up to several months when defined in terms of softening, water loss and resistance to postharvest biotic infection. However, it is not known whether this extension in āshelf lifeā is in fact a desirable objective from the perspective of nutritional quality of the fruits. The aim of this work was to use a metabolomics approach join to genomic tools to characterize compositional changes (sugars, amino acids, organic acids and carotenoids) of non-softening tomato mutants reported (DFD, NOR and RIN) in comparison with the normally softening fruits (Ailsa Craig and M82) during ripening and postharvest shelf-life. Important results related with ripening gene expression and metabolic evolutions are shown
Gr and hp-1 tomato mutants unveil unprecedented interactions between arbuscular mycorrhizal symbiosis and fruit ripening
*omeSOM: a software for clustering and visualization of transcriptional and metabolite data mined from interspecific crosses of crop plants
Background: Modern biology uses experimental systems that involve the exploration of phenotypic variation as a result of the recombination of several genomes. Such systems are useful to investigate the functional evolution of metabolic networks. One such approach is the analysis of transcript and metabolite profiles. These kinds of studies generate a large amount of data, which require dedicated computational tools for their analysis.Results: This paper presents a novel software named *omeSOM (transcript/metabol-ome Self Organizing Map) that implements a neural model for biological data clustering and visualization. It allows the discovery of relationships between changes in transcripts and metabolites of crop plants harboring introgressed exotic alleles and furthermore, its use can be extended to other type of omics data. The software is focused on the easy identification of groups including different molecular entities, independently of the number of clusters formed. The *omeSOM software provides easy-to-visualize interfaces for the identification of coordinated variations in the co-expressed genes and co-accumulated metabolites. Additionally, this information is linked to the most widely used gene annotation and metabolic pathway databases.Conclusions: *omeSOM is a software designed to give support to the data mining task of metabolic and transcriptional datasets derived from different databases. It provides a user-friendly interface and offers several visualization features, easy to understand by non-expert users. Therefore, *omeSOM provides support for data mining tasks and it is applicable to basic research as well as applied breeding programs. The software and a sample dataset are available free of charge at http://sourcesinc.sourceforge.net/omesom/.Fil: Milone, Diego Humberto. Universidad Nacional del Litoral. Facultad de IngenierĆa y Ciencias HĆdricas. Departamento de InformĆ”tica. Laboratorio de Investigaciones en SeƱales e Inteligencia Computacional; Argentina. Consejo Nacional de Investigaciones CientĆficas y TĆ©cnicas. Centro CientĆfico TecnolĆ³gico Conicet - Santa Fe; ArgentinaFil: Stegmayer, Georgina. Consejo Nacional de Investigaciones CientĆficas y TĆ©cnicas. Centro CientĆfico TecnolĆ³gico Conicet - Santa Fe; Argentina. Universidad TecnolĆ³gica Nacional. Facultad Regional Santa Fe. Centro de InvestigaciĆ³n y Desarrollo de IngenierĆa en Sistemas de InformaciĆ³n; ArgentinaFil: Kamenetzky, Laura. Instituto Nacional de TecnologĆa Agropecuaria. Centro de InvestigaciĆ³n en Ciencias Veterinarias y AgronĆ³micas. Instituto de BiotecnologĆa; Argentina. Consejo Nacional de Investigaciones CientĆficas y TĆ©cnicas. Centro CientĆfico TecnolĆ³gico Conicet - Santa Fe; ArgentinaFil: LĆ³pez, Mariana. Instituto Nacional de TecnologĆa Agropecuaria. Centro de InvestigaciĆ³n en Ciencias Veterinarias y AgronĆ³micas. Instituto de BiotecnologĆa; ArgentinaFil: Lee, Je M.. Cornell University; Estados UnidosFil: Giovannoni, James J.. Cornell University; Estados UnidosFil: Carrari, Fernando Oscar. Consejo Nacional de Investigaciones CientĆficas y TĆ©cnicas. Centro CientĆfico TecnolĆ³gico Conicet - Santa Fe; Argentina. Instituto Nacional de TecnologĆa Agropecuaria. Centro de InvestigaciĆ³n en Ciencias Veterinarias y AgronĆ³micas. Instituto de BiotecnologĆa; Argentin
Metabolomics should be deployed in the identification and characterization of gene-edited crops
Abstract Gene editing techniques are currently revolutionizing biology allowing far greater precision than previous mutagenic and transgenic approaches. They are becoming applicable to a wide range of plant species and biological processes. Gene editing can rapidly improve a range of crop traits including disease resistance, abiotic stress tolerance, yield, nutritional quality and additional consumer traits. Unlike transgenic approaches, however, it is not facile to forensically detect gene-editing events at the molecular level, as no foreign DNA exists in the elite line. These limitations in molecular detection approaches are likely to focus more attention on the products generated from the technology, than the process per se. Rapid advances in sequencing and genome assembly increasingly facilitate genome sequencing as a means of characterizing new varieties generated by gene editing techniques. Nevertheless, subtle edits such as single base changes or small deletions may be difficult to distinguish from normal variation within a genotype. Given these emerging scenarios, downstream āomicsā technologies reflective of edited affects, such as metabolomics, need to be utilized in a more prominent manner to fully assess compositional changes in novel foodstuffs. To achieve this goal, metabolomics or ānon-targeted metabolite analysisā needs to make significant advances to deliver greater representation across the metabolome. With the emergence of new edited crop varieties we advocate; (i) concerted efforts in the advancement of āomicsā technologies such as metabolomics and (ii) redress the use of the technology in the regulatory assessment for metabolically-engineered biotech crops
Virus-induced gene complementation reveals a transcription factor network in modulation of tomato fruit ripening
Plant virus technology, in particular virus-induced gene silencing, is a widely used reverse- and forward-genetics tool in plant functional genomics. However the potential of virus technology to express genes to induce phenotypes or to complement mutants in order to understand the function of plant genes is not well documented. Here we exploit Potato virus X as a tool for virus-induced gene complementation (VIGC). Using VIGC in tomato, we demonstrated that ectopic viral expression of LeMADS-RIN, which encodes a MADS-box transcription factor (TF), resulted in functional complementation of the non-ripening rin mutant phenotype and caused fruits to ripen. Comparative gene expression analysis indicated that LeMADS-RIN up-regulated expression of the SBP-box (SQUAMOSA promoter binding protein-like) gene LeSPL-CNR, but down-regulated the expression of LeHB-1, an HD-Zip homeobox TF gene. Our data support the hypothesis that a transcriptional network may exist among key TFs in the modulation of fruit ripening in tomato
Comparative BAC end sequence analysis of tomato and potato reveals overrepresentation of specific gene families in potato
<p>Abstract</p> <p>Background</p> <p>Tomato (<it>Solanum lycopersicon</it>) and potato (<it>S. tuberosum</it>) are two economically important crop species, the genomes of which are currently being sequenced. This study presents a first genome-wide analysis of these two species, based on two large collections of BAC end sequences representing approximately 19% of the tomato genome and 10% of the potato genome.</p> <p>Results</p> <p>The tomato genome has a higher repeat content than the potato genome, primarily due to a higher number of retrotransposon insertions in the tomato genome. On the other hand, simple sequence repeats are more abundant in potato than in tomato. The two genomes also differ in the frequency distribution of SSR motifs. Based on EST and protein alignments, potato appears to contain up to 6,400 more putative coding regions than tomato. Major gene families such as cytochrome P450 mono-oxygenases and serine-threonine protein kinases are significantly overrepresented in potato, compared to tomato. Moreover, the P450 superfamily appears to have expanded spectacularly in both species compared to <it>Arabidopsis thaliana</it>, suggesting an expanded network of secondary metabolic pathways in the <it>Solanaceae</it>. Both tomato and potato appear to have a low level of microsynteny with <it>A. thaliana</it>. A higher degree of synteny was observed with <it>Populus trichocarpa</it>, specifically in the region between 15.2 and 19.4 Mb on <it>P. trichocarpa </it>chromosome 10.</p> <p>Conclusion</p> <p>The findings in this paper present a first glimpse into the evolution of Solanaceous genomes, both within the family and relative to other plant species. When the complete genome sequences of these species become available, whole-genome comparisons and protein- or repeat-family specific studies may shed more light on the observations made here.</p
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A SEPALLATA gene is involved in the development and ripening of strawberry (Fragaria xananassa Duch.) fruit, a non-climacteric tissue
Climacteric and non-climacteric fruits have traditionally been viewed as representing two distinct programmes of
ripening associated with differential respiration and ethylene hormone effects. In climacteric fruits, such as tomato
and banana, the ripening process is marked by increased respiration and is induced and co-ordinated by ethylene,
while in non-climacteric fruits, such as strawberry and grape, it is controlled by an ethylene-independent process
with little change in respiration rate. The two contrasting mechanisms, however, both lead to texture, colour, and
flavour changes that probably reflect some common programmes of regulatory control. It has been shown that
a SEPALLATA(SEP)4-like gene is necessary for normal ripening in tomato. It has been demonstrated here that
silencing a fruit-related SEP1/2-like (FaMADS9) gene in strawberry leads to the inhibition of normal development and
ripening in the petal, achene, and receptacle tissues. In addition, analysis of transcriptome profiles reveals pleiotropic
effects of FaMADS9 on fruit development and ripening-related gene expression. It is concluded that SEP
genes play a central role in the developmental regulation of ripening in both climacteric and non-climacteric fruits.
These findings provide important information to extend the molecular control of ripening in a non-climacteric fruit
beyond the limited genetic and cultural options currently available
MaMADS2 repression in banana fruits modifies hormone synthesis and signalling pathways prior to climacteric stage
Background: While the role of ethylene in fruit ripening has been widely studied, the contributions of additional plant hormones are less clear. Here we examined the interactions between the transcription factor MaMADS2-box which plays a major role in banana fruit ripening and hormonal regulation. Specifically, we used MaMADS2 repressed lines in transcriptome and hormonal analyses throughout ripening and assessed hormone and gene expression perturbations as compared to wild-type (WT) control fruit. Results: Our analyses revealed major differences in hormones levels and in expression of hormone synthesis and signaling genes mediated by MaMADS2 especially in preclimacteric pulp. Genes encoding ethylene biosynthesis enzymes had lower expression in the pulp of the repressed lines, consistent with reduced ethylene production. Generally, the expression of other hormone (auxin, gibberellins, abscisic acid, jasmonic acid and salicylic acid) response pathway genes were down regulated in the WT pulp prior to ripening, but remained high in MaMADS2 repressed lines. Hormone levels of abscisic acid were also higher, however, active gibberellin levels were lower and auxin levels were similar with MaMADS2 repression as compared to WT. Although abscisic level was higher in MaMADS2 repression, exogenous abscisic acid shortened the time to ethylene production and increased MaMADS2 mRNA accumulation in WT. Exogenous ethylene did not influence abscisic acid level. CRE - a cytokinin receptor, increased its expression during maturation in WT and was lower especially at prebreaker in the repressed line and zeatin level was lower at mature green of the repressed line in comparison to WT. Conclusions: In addition to previously reported effects of MaMADS2 on ethylene, this transcription factor also influences other plant hormones, particularly at the pre-climacteric stage. The cytokinin pathway may play a previously unanticipated role via MaMADS2 in banana ripening. Finally, abscisic acid enhances MaMADS2 expression to promote ripening, but the transcription factor in turn auto inhibits ABA synthesis and signaling. Together, these results demonstrate a complex interaction of plant hormones and banana fruit ripening mediated by MaMADS2
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