120 research outputs found
Decoding hybridization barriers: the molecular and genetic orchestration of the triploid block in Arabidopsis thaliana
No full textPlant evolution has been greatly influenced by polyploidization phenomena. Polyploid plants yield more and are more resistant to unfavorable environments than their diploid relatives. The triploid block, a postzygotic barrier that causes failure of endosperm development and thus seed arrest, often prevents polyploid breeding. Alterations in the parental dose in interploidy crosses alter endosperm development by changing the correct maternal: paternal ratio (2m:1p) that this tissue requires to properly fulfill its proliferation and cellularization. After many years of research, the study of epigenetic regulation of gene expression during seed development has greatly increased our understanding of the triploid block. In plants, epigenetic regulation of genes has been shown to play a critical role in transcriptional control. This may be important for identifying novel and unexpected epigenetic mechanisms in the plant genome. Recent advances in understanding how epigenetic mechanisms control the expression of imprinted genes in seeds have contributed to understanding how different seed compartments interact at fertilization for successful seed formation. We here also review the potential role of maternally derived sporophytic tissues (seed coat) in the establishment of the triploid block. We also present a data analysis that includes spatiotemporal expression patterns of key genes involved in controlling hybridization barriers. This review provides an overview of the triploid block in plants, discussing how understanding its epigenetic regulation could offer new strategies to overcome hybridization barriers. We explore how these insights may enhance crop productivity and resilience
Developmental signals in the 21st century; new tools and advances in plant signaling
No full textThis special issue includes different research papers and reviews that studied the role of signaling cascades controlling both plant developmental processes and plant response mechanisms to biotic and abiotic stresses [...]
Plant cell walls tackling climate change : insights into plant cell wall remodeling, its regulation, and biotechnological strategies to improve crop adaptations and photosynthesis in response to global warming
No full textPlant cell wall (CW) is a complex and intricate structure that performs several functions throughout the plant life cycle. The CW of plants is critical to the maintenance of cells’ structural integrity by resisting internal hydrostatic pressures, providing flexibility to support cell division and expansion during tissue differentiation, and acting as an environmental barrier that protects the cells in response to abiotic stress. Plant CW, comprised primarily of polysaccharides, represents the largest sink for photosynthetically fixed carbon, both in plants and in the biosphere. The CW structure is highly varied, not only between plant species but also among different organs, tissues, and cell types in the same organism. During the developmental processes, the main CW components, i.e., cellulose, pectins, hemicelluloses, and different types of CW-glycoproteins, interact constantly with each other and with the environment to maintain cell homeostasis. Differentiation processes are altered by positional effect and are also tightly linked to environmental changes, affecting CW both at the molecular and biochemical levels. The negative effect of climate change on the environment is multifaceted, from high temperatures, altered concentrations of greenhouse gases such as increasing CO2 in the atmosphere, soil salinity, and drought, to increasing frequency of extreme weather events taking place concomitantly, therefore, climate change affects crop productivity in multiple ways. Rising CO2 concentration in the atmosphere is expected to increase photosynthetic rates, especially at high temperatures and under water-limited conditions. This review aims to synthesize current knowledge regarding the effects of climate change on CW biogenesis and modification. We discuss specific cases in crops of interest carrying cell wall modifications that enhance tolerance to climate change-related stresses; from cereals such as rice, wheat, barley, or maize to dicots of interest such as brassica oilseed, cotton, soybean, tomato, or potato. This information could be used for the rational design of genetic engineering traits that aim to increase the stress tolerance in key crops. Future growing conditions expose plants to variable and extreme climate change factors, which negatively impact global agriculture, and therefore further research in this area is critical
Carbohydrate reserves and seed development : an overview
No full textSeeds are one of the most important food sources, providing humans and animals with essential nutrients. These nutrients include carbohydrates, lipids, proteins, vitamins and minerals. Carbohydrates are one of the main energy sources for both plant and animal cells and play a fundamental role in seed development, human nutrition and the food industry. Many studies have focused on the molecular pathways that control carbohydrate flow during seed development in monocot and dicot species. For this reason, an overview of seed biodiversity focused on the multiple metabolic and physiological mechanisms that govern seed carbohydrate storage function in the plant kingdom is required. A large number of mutants affecting carbohydrate metabolism, which display defective seed development, are currently available for many plant species. The physiological, biochemical and biomolecular study of such mutants has led researchers to understand better how metabolism of carbohydrates works in plants and the critical role that these carbohydrates, and especially starch, play during seed development. In this review, we summarize and analyze the newest findings related to carbohydrate metabolism’s effects on seed development, pointing out key regulatory genes and enzymes that influence seed sugar import and metabolism. Our review also aims to provide guidelines for future research in the field and in this way to assist seed quality optimization by targeted genetic engineering and classical breeding programs
Unusual nighttime impulsive<i>fo</i>F2 enhancement below the southern anomaly crest under geomagnetically quiet conditions
No full textAn unusual nighttime impulsive electron density enhancement was observed on 6 March 2010 over a wide region of South America, below the southern crest of the equatorial anomaly, under low solar activity and quiet geomagnetic conditions. The phenomenon was observed almost simultaneously by the F2 layer critical frequency ( foF2) recorded at three ionospheric stations which are widely distributed in space, namely Cachoeira Paulista (22.4°S, 44.6°W, magnetic latitude 13.4°S), São José dos Campos (23.2°S, 45.9°W, magnetic latitude 14.1°S), Brazil, and Tucumán (26.9°S, 65.4°W, magnetic latitude 16.8°S), Argentina. Although in a more restricted region over Tucumán, the phenomenon was also observed by the total electron content (TEC) maps computed by usingmeasurements from 12 GPS receivers. The investigated phenomenon is very particular because besides being of brief duration, it is characterized by a pronounced compression of the ionosphere. This compression was clearly visible both by the virtual height of the base of the F region (h′F) recorded at the aforementioned ionospheric stations, and by both the vertical electron density profiles and the slab thickness computed over Tucumán. Consequently, neither an enhanced fountain effect nor plasma diffusion from the plasmasphere can be considered as the single cause of this unusual event. A thorough analysis of isoheight and isofrequency ionosonde plots suggest that traveling ionospheric disturbances (TIDs) caused by gravity wave (GW) propagation could have likely played a significant role in causing the phenomenonFil: Pezzopane, M.. Istituto Nazionale di Geofisica e Vulcanologia; ItaliaFil: Fagundes, P. R.. Física E Astronomia, Universidade Do Vale Do Paraiba; BrasilFil: Ciraolo, L.. Ifac-crn; ItaliaFil: Correia, E.. Física E Astronomia, Universidade Do Vale Do Paraiba; BrasilFil: Cabrera, Miguel Angel. Laboratorio de Telecomunicaciones; ArgentinaFil: Ezquer, Rodolfo Gerardo. Centro de Investigación de Atmósfera Superior y Radiopr; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin
Molecular mechanisms of BASIC PENTACYSTEINE PROTEINS (BPCs) and the MADS-box factor SVP in the regulation of homeotic genes in Arabidopsis
No full textThe Arabidopsis transcription factor BPCs family is composed of seven members divided into three classes, based on their protein sequence similarity. BPCs bind the regulatory sequence of the homeotic gene SEEDSTICK (STK) promoter together with the MADS-box factor SHORT VEGETATIVE PHASE (SVP) . We show that MADS-box binding sites on the STK promoter region are necessary for STK correct spatial expression. To study the contribution of BPCs of class II to the regulation of the homeotic gene we generated the quintuple bpc12346 mutant. Through ChIP experiments, we found that SVP binds the genomic region of STK even in the absence of BPCs, whereas BPCs need SVP for the binding of the STK promoter. Besides, BPCs mutations affect STK expression in the flower. Moreover we analyzed the repressive trimethylation mark at Lys-27 in histone H3 in STK regulatory regions and we found that it’s reduced in bpc12346 mutant suggesting a direct role of chromatin modification in the regulation of STK expression mediated by BPCs. Our results provide insights into the molecular mechanisms that drive transcription regulation in plants and investigate the involvement of a protein complex in which BPCs and MADS-box might cooperate to regulate the expression of homeotic genes during development
Acquisition, Maintenance and Relapse-Like Alcohol Drinking: Lessons from the UChB Rat Line
No full text© 2017 Israel, Karahanian, Ezquer, Morales, Ezquer, Rivera-Meza, Herrera-Marschitz and Quintanilla. This review article addresses the biological factors that influence: (i) the acquisition of alcohol intake; (ii) the maintenance of chronic alcohol intake; and (iii) alcohol relapse-like drinking behavior in animals bred for their high-ethanol intake. Data from several rat strains/lines strongly suggest that catalase-mediated brain oxidation of ethanol into acetaldehyde is an absolute requirement (up 80%–95%) for rats to display ethanol’s reinforcing effects and to initiate chronic ethanol intake. Acetaldehyde binds non-enzymatically to dopamine forming salsolinol, a compound that is selfadministered. In UChB rats, salsolinol: (a) generates marked sensitization to the motivational effects of ethanol; and (b) strongly promotes binge-like drinking. The specificity of salsolinol actions is shown by the finding that only the R-salsolinol enantiomer but not S-salsolinol accounted for the lat
Evolutionary studies of the bHLH transcription factors belonging to MBW complex: their role in seed development
No full textBackground and aims: The MBW complex consist of proteins belonging to three major families MYB, bHLH and WDR, involved in various processes throughout plant development: epidermal cell development, mucilage secretory cells and flavonoid biosynthesis. Recently, it has been reported that TT8, encoding a bHLH transcription factor, is involved in the biosynthesis of flavonoids in the seed coat and it also plays a role in bypassing the postzygotic barrier resulting from an unbalance in genetic loads of the parental lines. Here we focus on the functional evolution, in seed development, of the bHLH proteins that are part of the MBW complex complemented with a literature review. Methods: Phylogenetic analyses performed across seed plants, and expression analyses in the reproductive tissues of four selected angiosperms: Arabidopsis thaliana, Brassica napus, Capsella rubella and Solanum lycopersicum, allowing us to hypothesize on the evolution of its functions. Key results: TT8 expression in the innermost layer of the seed coat is conserved in the selected angiosperms. However, except for Arabidopsis, TT8 is also expressed in ovules, carpels and fruits. The homologs belonging to TT8's sister clade, EGL3/GL3, involved in trichome development, are expressed in the outermost layer of the seed coat, suggesting potential roles in mucilage. Conclusions: The ancestral function of these genes appears to be flavonoid biosynthesis and the conservation of TT8 expression patterns in the innermost layer of the seed coat in angiosperms suggests that their function in postzygotic barriers may also be conserved. Moreover, the literature review and the results of the present study suggest a sophisticated association, linking the mechanisms of action of these genes to the cross-communication activity between the different tissues of the seed. Thus, it provides avenues to study the mechanisms of action of TT8, in the postzygotic triploid block, which is crucial since it impacts seed development in unbalanced crosses
METHOD FOR CHANGING THE DEVELOPMENT PATTERN, INCREASING THE GROWTH AND ACCUMULATION OF STARCH, CHANGING THE STRUCTURE OF STARCH AND INCREASING THE RESISTANCE TO HYDRIC STRESS IN PLANTS
No full textRIASSUNTO WO2011135121
L'invenzione riguarda un metodo per modificare il modello di sviluppo, aumentando la crescita e
l'accumulo di amido, modificare la struttura di amido e aumentare la resistenza allo stress idrico
nelle piante. Il metodo prevede piante in un'atmosfera contenente elementi volatili emessi da un
microrganismo coltivando, senza che vi sia alcun contatto fisico tra il microrganismo e la pianta. Il
metodo si basa sulla scoperta che gli elementi volatili emessi da batteri Gram Gram-positivi o
Gram-negativi, lieviti e funghi microscopici stimolano un aumento della crescita delle piante in
generale, con un aumento della lunghezza, il numero di foglie e / o il numero di rami della pianta,
un aumento della amido accumulato ei cambiamenti strutturali a detto biopolimero, e modifica del
disegno di sviluppo, con un aumento di boccioli floreali. Una maggiore resistenza allo stress idrico
può anche essere osservato, in aggiunta a un aumento di amido in fogli separati da piante intere.The invention relates to a method for changing the development pattern, increasing the growth and accumulation of starch, changing the structure of starch and increasing the resistance to hydric stress in plants. The method involves cultivating plants in an atmosphere containing volatile elements emitted by a microorganism, without there being any physical contact between the microorganism and the plant. The method is based on the discovery that the volatile elements emitted by Gram-positive or Gram-negative Gram bacteria, yeast and microscopic fungi stimulate an increase in the growth of plants in general, with an increase in the length, the number of leaves and/or the number of branches of the plant, an increase in the accumulated starch and structural change to said biopolymer, and modification of the development pattern, with an increase in floral buds. An increased resistance to hydric stress can also be observed, in addition to an increase in starch in leaves separated from whole plants
Effect of water supply regimes on physiological parameters and productivity in eggplant grown under mediterranean climate conditions
No full textDrought has affected agriculture and intensified water scarcity. The effect of two irrigation regimes was evaluated on 13 eggplant genotypes selected as diverging for several fruit/plant qualitative traits, yield and drought tolerance. Two commercial varieties commonly used by growers in Morocco were tested. The irrigation treatments consisted of two different conditions: (i) control irrigation (Tr-C) adopted by the grower; (ii) water shortage of 50% of the amount of this irrigation (Tr-50%). Results showed that reduced water supply significantly impacted growth and quality parameters of each genotype/variety (p < 0.001) between treatments, particularly, traits such as plant height, number of flowers and leaves. Non-significant differences between treatments were observed Fv/Fm, DI0/CS0 and ABS/CS0 ratios. In terms of relative water content (RWC), genotype C10 showed remarkable drought resilience, with only a 4.12% reduction. Water stress resulted in significant reductions in the number of fruits for C8 by 49.58% and yield per plant for the genotype B1 by 39.19%. Notably, genotypes C10 and C13 demonstrated significantly better performance compared to the other genotypes, yielding 1.48 and 1.53 kg/plant, respectively, while commercial varieties A and V produced 1.98 kg/plant and 1.86 kg/plant. These results provide valuable information for the selecting and breeding of tolerant eggplant genotypes under drought-prone environments
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