RESUMEN
With the imminence of global climate changes that affect the temperature and the rainfall uniformity, it is growing the concern about the adaptation of crops to the water deficit. Thus, the objective of this study was to evaluate alterations in physiological and enzymatic mechanisms during the germination process of sesame seeds under different water availability. To simulate the water restriction we used PEG6000, a high molecular weight molecule that does not penetrate the seed structure but allows different osmotic potentials. The treatments were -0.1, -0.2, and -0.3 MPa, and the control. Germination, first-count germination, germination velocity index, and length and dry mass of the hypocotyl and radicle were performed. The seeds were weighed before and after treatments every 3 h. After each weighing, 100 seeds were taken for analysis of the enzymes alcohol dehydrogenase (ADH), malate dehydrogenase, esterase, catalase (CAT), superoxide dismutase (SOD), isocitrate lyase (ICL), and glutamate dehydrogenase (GTDH). The statistical design was completely randomized with five replications. PEG6000 prolonged ADH activity during the beginning of germination, maintaining the anaerobic metabolism for longer. Subsequently, their activity was reduced, as well as ICL, favoring the deterioration of the seeds that take the time to germinate. Behavior was evidenced by the appearance of SOD, CAT, and GTDH isoforms after 24 h of imbibition when water restriction was imposed. Therefore, the PEG600 is efficient in simulating water deficit conditions in future scenarios of climate change, offering impotent information regarding the germination behavior of the plants under these conditions.
Asunto(s)
Presión Osmótica , Semillas/enzimología , Sesamum/enzimología , Alcohol Deshidrogenasa/metabolismo , Catalasa/metabolismo , Esterasas/metabolismo , Germinación , Glutamato Deshidrogenasa/metabolismo , Isocitratoliasa/metabolismo , Malato Deshidrogenasa/metabolismo , Proteínas de Plantas/metabolismo , Semillas/crecimiento & desarrollo , Semillas/metabolismo , Sesamum/crecimiento & desarrollo , Sesamum/metabolismo , Superóxido Dismutasa/metabolismoRESUMEN
Low water availability is one of the factors that limit agricultural crop development, and hence the development of genotypes with increased water stress tolerance is a challenge in plant breeding programs. Heat-resistant proteins have been widely studied, and are reported to participate in various developmental processes and to accumulate in response to stress. This study aimed to evaluate heat-resistant protein expression under water stress conditions during the germination of maize seed inbreed lines differing in their water stress tolerance. Maize seed lines 91 and 64 were soaked in 0, -0.3, -0.6, and -0.9 MPa water potential for 0, 6, 12, 18, and 24 h. Line 91 is considered more water stress-tolerant than line 64. The analysis of heat-resistant protein expression was made by gel electrophoresis and spectrophotometry. In general, higher expression of heat-resistant proteins was observed in seeds from line 64 subjected to shorter soaking periods and lower water potentials. However, in the water stress-tolerant line 91, a higher expression was observed in seeds that were subjected to -0.3 and -0.6 MPa water potentials. In the absence of water stress, heat-resistant protein expression was reduced with increasing soaking period. Thus, there was a difference in heat-resistant protein expression among the seed lines differing in water stress tolerance. Increased heat-resistant protein expression was observed in seeds from line 91 when subjected to water stress conditions for longer soaking periods.
Asunto(s)
Germinación , Proteínas de Choque Térmico/genética , Proteínas de Plantas/genética , Semillas/metabolismo , Zea mays/metabolismo , Deshidratación/genética , Deshidratación/metabolismo , Expresión Génica , Regulación de la Expresión Génica de las Plantas , Proteínas de Choque Térmico/metabolismo , Respuesta al Choque Térmico , Calor , Proteínas de Plantas/metabolismo , Semillas/genética , Semillas/crecimiento & desarrollo , Zea mays/genética , Zea mays/crecimiento & desarrolloRESUMEN
Phytohormones have different characteristics and functions, and they may be subject to changes in their gene expression and synthesis during seed development. In this study, we evaluated the physiological qualities of habanero peppers (Capsicum chinense Jacquin) during seed development and the expression of genes involved in germination. Seeds were obtained from fruits harvested at different stages of development [i.e., 14, 21, 28, 35, 42, 49, 56, 63, and 70 days after anthesis (DAA)]. Immediately after harvesting, the seeds were subjected to various tests to determine moisture content, germination, first count germination, and seedling emergence. Real-time polymerase chain reaction was used to evaluate the expression of various genes, including MAN2, NCED, B73, ICL6, and GA3ox. Electrophoresis was used to assess the expression of various enzymes, including α-amylase, isocitrate-lyase, and endo-ß-mannanase. Habanero peppers harvested at 70 DAA and subjected to 7 days of rest exhibited higher germination rates and vigor compared to those harvested at all other developmental stages. Peppers harvested at 63 DAA without drying exhibited higher α amylase and AmyB73 gene expression levels. Peppers harvested at 70 DAA with 7 days of rest exhibited higher endo-ß-mannanase expression levels. MAN2 gene expression increased during the development of non-dried seeds until 70 DAA. Peppers harvested at 42 DAA exhibited the highest isocitrate-lyase and ICL6 gene activity levels in comparison to those at all other developmental stages.
Asunto(s)
Capsicum/genética , Frutas/genética , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Semillas/genética , Capsicum/crecimiento & desarrollo , Capsicum/metabolismo , Frutas/crecimiento & desarrollo , Frutas/metabolismo , Germinación , Isocitratoliasa/genética , Isocitratoliasa/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Proteínas de Plantas/metabolismo , Plantones/genética , Plantones/crecimiento & desarrollo , Plantones/metabolismo , Semillas/crecimiento & desarrollo , Semillas/metabolismo , alfa-Amilasas/genética , alfa-Amilasas/metabolismo , beta-Manosidasa/genética , beta-Manosidasa/metabolismoRESUMEN
The identification of genes related to heat tolerance is fundamental for the development of high-quality seeds that are tolerant to heat stress condition. The objective of this study was to evaluate maize lineages and the gene expression involved in high temperature tolerance during germination using physiological tests, proteomics, and transcriptome analysis. Seeds from six maize lineages (30, 44, 54, 63, 64, and 91) with different levels of tolerance to high temperatures were used. Lineages 54 and 91 were observed to be more tolerant to high temperature conditions. The highest expression of α-amylase was observed in maize seeds from lineages 30 and 91 that were subjected to controlled deterioration. The highest expression of α-amylase was observed in maize seeds from lineages 30 and 91 that were subjected to controlled deterioration; with the controlled deterioration, the highest level of gene expression did not occur in the most tolerant materials; the association of lower expression of genes involved in heat-resistant protein systems was observed in seeds from lineage 44, which were more susceptible to high temperatures, and the highest gene expression of LEA D-34, ZmAN13, and AOX-1 was observed in seeds from lineage 64 when submitted to controlled deterioration.
Asunto(s)
Germinación/genética , Semillas/genética , Estrés Fisiológico/genética , Zea mays/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/biosíntesis , Proteínas de Plantas/genética , Semillas/fisiología , Temperatura , Zea mays/fisiología , alfa-Amilasas/biosíntesisRESUMEN
In this study, we analyzed heterosis, amylase enzyme gene expression, and the physiological quality of maize seeds with different genotypes and sizes, which were subjected to aging and not subjected to aging. We used seeds from 2 maize lines that differed with regard to physiological quality, the hybrid, and the reciprocal hybrid; they were classified into 2 sizes and were subjected to aging and not subjected to aging. Physiological quality was assessed by performing tests for germination, emergence, emergence speed index, and artificial aging. Expressions of the genes alpha amylase B73, alpha amylase (LOC542522), isoamylase mRNA clone 353244, and the endogenous controls ubiquitin and alcohol dehydrogenase in the seeds were studied using quantitative real-time-polymerase chain reaction. We observed heterosis for seed quality and for expression of amylase genes in the genotypes studied. We found no difference in seed quality between large and small seeds.
Asunto(s)
Amilasas/genética , Proteínas de Plantas/genética , Semillas/enzimología , Zea mays/enzimología , Amilasas/metabolismo , Expresión Génica , Genes de Plantas , Hibridación Genética , Proteínas de Plantas/metabolismo , Semillas/genética , Semillas/crecimiento & desarrollo , Zea mays/genética , Zea mays/crecimiento & desarrolloRESUMEN
The increasing number of protected and registered cultivars and problems involving seed commercialization make distinction and identification of cultivars imperative. Millet (Pennisetum glaucum), a crop species with protected cultivars in Brazil, has been the target of seed piracy. Thus, with the objective of identifying different lots with regard to origin, we characterized six cultivars of commercialized millet of proven origin by means of the electrophoretic patterns of the isoenzymes alcohol dehydrogenase, esterase and glutamate oxaloacetate transaminase and by microsatellite markers, using primers specific for millet. The six cultivars were separated with four microsatellite loci. Based on this characterization, certification of genetic purity was undertaken for public domain commercialized seed lots. The isoenzymatic markers were also tested for stability of the patterns. Esterase patterns were altered in seeds with different physiological quality and health conditions, but this alteration did not hinder identification of the cultivars. It was observed that most of the millet seed lots commercialized in Brazil as being in public domain belong to other cultivars.
Asunto(s)
Repeticiones de Microsatélite/genética , Pennisetum/enzimología , Pennisetum/genética , Biomarcadores/análisis , Brasil , Marcadores Genéticos , Isoenzimas/análisis , Panicum/enzimología , Panicum/genética , Proteínas de Plantas/análisis , Semillas/química , Semillas/genéticaRESUMEN
Coffee (Coffea arabica L.) seeds are sensitive to desiccation and oxidative stress during drying processes. We investigated the effect of drying and moisture levels on germination-related gene expressions associated with enzymatic systems that prevent oxidative stress in coffee seeds. Coffee seeds collected at physiological maturity were subjected to slow and quick drying to 40, 30, 20, and 12% moisture levels (wet basis), and as the control, seeds without drying were used. The seeds' physiological quality was calculated as percentage of normal seedlings at 15 and 30 days, normal vigorous seedlings at 30 days, and cotyledonary leaves at 45 days. The isoenzymes esterase, catalase (CAT), peroxidase (POX), and endo-ß-mannanase expressions were electrophoretically analyzed. CAT and POX expressions were analyzed using RT-qPCR with specific primers constructed from the target gene sequences from the Brazilian Coffee Genome Database. Slow drying showed better physiological quality for seeds at 40 and 12% moisture levels, while quick drying was the most effective for seeds with 20% moisture. Sensitivity to water loss was confirmed by quick drying and activation of enzymes. CAT and POX transcriptions reduced during drying. RT-qPCR revealed a complex gene-expression pattern during the oxidative process, with high gene expression in wet seeds.
Asunto(s)
Coffea/enzimología , Coffea/genética , Desecación , Germinación/genética , Semillas/metabolismo , Carboxilesterasa/análisis , Carboxilesterasa/biosíntesis , Carboxilesterasa/genética , Catalasa/análisis , Catalasa/biosíntesis , Catalasa/genética , Coffea/metabolismo , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Manosidasas/análisis , Manosidasas/biosíntesis , Manosidasas/genética , Oxidación-Reducción , Estrés Oxidativo/genética , Peroxidasa/análisis , Peroxidasa/biosíntesis , Peroxidasa/genética , ARN Mensajero/biosíntesis , Especies Reactivas de Oxígeno/metabolismo , Semillas/genéticaRESUMEN
The study of gene expression in plants is fundamental, and understanding the molecular mechanisms involved in important biological processes, such as biochemical pathways or signaling that are used or manipulated in improvement programs, are key for the production of high-quality soybean seeds. Reports related to gene expression of lignin in seeds are scarce in the literature. We studied the expression of the phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase, 4-hydroxycinnamate 3-hydroxylase, and cinnamyl alcohol dehydrogenase genes involved in lignin biosynthesis during the development of soybean (Glycine max L. Merrill) seeds. As the endogenous control, the eukaryotic elongation factor 1-beta gene was used in two biological replicates performed in triplicate. Relative quantitative expression of these genes during the R4, R5, R6, and R7 development stages was analyzed. Real-time polymerase chain reaction was used for the gene expression study. The analyses were carried out in an ABI PRISM 7500 thermocycler using the comparative Ct method and SYBR Green to detect amplification. The seed samples at the R4 stage were chosen as calibrators. Increased expression of the cinnamate-4-hydroxylase and PAL genes occurred in soybean seeds at the R5 and R6 development stages. The cinnamyl alcohol dehydrogenase gene was expressed during the final development phases of soybean seeds. In low-lignin soybean cultivars, the higher expression of the PAL gene occurs at development stages R6 and R7. Activation of the genes involved in the lignin biosynthesis pathway occurs at the beginning of soybean seed development.
Asunto(s)
Genes de Plantas , Glycine max/metabolismo , Lignina/biosíntesis , Semillas/metabolismo , Transcripción Genética , Oxidorreductasas de Alcohol/genética , Oxidorreductasas de Alcohol/metabolismo , Regulación de la Expresión Génica de las Plantas , Lignina/genética , Fenilanina Amoníaco-Liasa/genética , Fenilanina Amoníaco-Liasa/metabolismo , Semillas/crecimiento & desarrollo , Glycine max/genética , Glycine max/crecimiento & desarrollo , Transcinamato 4-Monooxigenasa/genética , Transcinamato 4-Monooxigenasa/metabolismoRESUMEN
We quantified and characterized the expression of heat-resistant proteins during seed development of maize lines with distinct levels of tolerance to high drying temperature. A corn field was planted for multiplication of seeds of different lines, two tolerant and two non-tolerant to high drying temperatures. Harvest of the seeds was carried out at various stages of development and they were then subjected to tests of moisture content, germination, first count of germination, accelerated aging, and cold test. The seeds were stored in a freezer for later analysis of expression of heat-resistant proteins by means of real-time PCR, electrophoresis, and spectrophotometry. We observed that heat-resistant proteins are expressed in a differential manner in seeds from different lines and at different stages of development. The expression of heat-resistant proteins was earlier in lines tolerant to high drying temperatures. Greater germination and vigor values was found for seeds collected at the last stage of development.
Asunto(s)
Regulación de la Expresión Génica de las Plantas , Calor , Proteínas de Plantas/genética , Semillas/genética , Zea mays/genética , ADN de Plantas/genética , Electroforesis , Germinación/genética , Proteínas de Plantas/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Semillas/fisiología , Análisis de Secuencia de ADN , Espectrofotometría , Zea mays/fisiologíaRESUMEN
Brazilian legislation establishes a labeling limit for products that contain more than 1% material from genetically modified organisms (GMOs). We assessed the sensitivity of the lateral flow strip test in detection of the GMO corn varieties Bt11 and MON810 and the specificity and sensitivity of PCR techniques for their detection. For the strip test, the GMO seeds were mixed with conventional seeds at levels of 0.2, 0.4 and 0.8% for Bt11, and 0.4, 0.8 and 1.6% for MON810. Three different methodologies were assessed and whole seeds, their endosperm and embryonic axis were used. For the PCR technique, the GMO seeds of each of the two varieties were mixed with conventional seeds at levels of 20, 10, 5, 2, 1, and 0.5%. The seeds were ground and the DNA extracted. For detection of the GMO material, specific primers were used for MON810 and Bt11 and maize zein as an endogenous control. The sensitivity of the strip test varied for both maize varieties and methodologies. The test was positive for Bt11 only at 0.8%, in contrast with the detection limit of 0.4% indicated by the manufacturer. In the multiplex PCR, the primers proved to be specific for the different varieties. These varieties were detected in samples with one GMO seed in 100. Thus, this technique proved to be efficient in detecting contaminations equal to or greater than 1%.
Asunto(s)
Límite de Detección , Reacción en Cadena de la Polimerasa/métodos , Zea mays/genética , Brasil , Genes de Plantas/genética , Plantas Modificadas Genéticamente , Zeína/genéticaRESUMEN
quantitative trait locus (QTL) mapping and identification of traits of agronomic importance is important in the process of molecular marker-assisted selection in breeding programs. The molecular map of maize is well saturated and QTL and simple sequence repeat (SSR) markers have been identified, whereas few markers linked to seed quality traits are included. The present study aimed to identify QTL and the gene action and to quantify the effects of these regions in the phenotypic variation related to maize tolerance to high seed drying temperature. SSR markers and 129 segregating families of F2 plants of the cross of intolerant and tolerant lines were used in regression and composite interval mapping methods. Three maize QTL associated with tolerance to high seed drying temperature were identified and mapped to chromosomes 6 and 8, explaining 39% of the phenotypic variation of the trait with additive, dominance and overdominance gene action. These markers seem to be effectively associated with the evaluated trait, since all were mapped near genes whose expression products were associated with seed desiccation tolerance.