RESUMEN
Castor (Ricinus communis) is a relevant industrial oilseed feedstock for many industrial applications, being globally mainly cultivated by smallholder farmers in semiarid areas, where abiotic stresses predominate. Therefore, susceptible to generating reactive oxygen species (ROS) and subsequent oxidative stress, compromising cell metabolism upon seed imbibition and germination, seedling and crop establishment, and yield. The present study evaluated the consequences of water restriction by Polyethylene glycol (PEG) and Sodium chloride (NaCl) on cell cycle and metabolism reactivation on germinability, seedling growth, and vigor parameters in 2 commercial castor genotypes (Nordestina and Paraguaçu). PEG water restriction inhibited germination completely at -0.23 MPa or higher, presumably due to reduced oxygen availability. The restrictive effects of NaCl saline stress on germination were observed only from -0.46 MPa onwards, affecting dry mass accumulation and the production of normal seedlings. In general, superoxide dismutase (SOD) activity increased in NaCl -0.23 MPa, whereas its modulation during the onset of imbibition (24h) seemed to depend on its initial levels in dry seeds in a genotype-specific manner, therefore, resulting in the higher stress tolerance of Nordestina compared to Paraguaçu. Overall, results show that Castor germination and seedling development are more sensitive to the restrictive effects of PEG than NaCl at similar osmotic potentials, contributing to a better understanding of the responses to water restriction stresses by different Castor genotypes. Ultimately, SOD may constitute a potential marker for characterizing castor genotypes in stressful situations during germination, early seedling, and crop establishment, and a target for breeding for Castor-improved stress tolerance.
Asunto(s)
Ricinus communis , Plantones , Plantones/metabolismo , Cloruro de Sodio/farmacología , Cloruro de Sodio/metabolismo , Ricinus communis/genética , Polietilenglicoles/farmacología , Polietilenglicoles/metabolismo , Germinación , Ciclo Celular , Semillas/metabolismo , Agua/metabolismo , Superóxido Dismutasa/metabolismoRESUMEN
OBJECTIVE: The purpose of this study was to develop a method for the isolation, culture, and PEG-mediated protoplast transfection from leaves of in vitro-grown plants of Ricinus communis. RESULTS: Factors such as the enzymatic composition and the incubation time were evaluated. The enzymatic solution, containing 1.6% Cellulase-R10 and 0.8% Macerozyme-R10, with 16 h of incubation, was the best condition to achieve a high protoplast yield (481.16 × 104 protoplasts/g FW) with a high percentage of viability (95%). The combination and concentration of enzymes have been shown to affect the protoplast isolation efficiency significantly. Furthermore, we found that a higher number of protoplasts (8.5 × 105 protoplast/g FW) was obtained at a longer incubation time, but their viability decreased. We obtained a simple and efficient protocol to isolate protoplast from Ricinus communis leaves and culture. A PEG-mediated protoplast transfection protocol was also established to introduce plasmid DNA into Ricinus communis genotypes cultivated in Colombia. Thus, strengthening advances in the genetic improvement processes for this crop are presented.
Asunto(s)
Ricinus communis , Ricinus communis/genética , Protoplastos , Ricinus/genética , Hojas de la Planta/genética , TransfecciónRESUMEN
Castor bean (Ricinus communis L.) can withstand long periods of water deficit and high temperatures, and therefore has been recognized as a drought-resistant plant species, allowing the study of gene networks involved in drought response and tolerance. The identification of genes networks related to drought response in this plant may yield important information in the characterization of molecular mechanisms correlating changes in the gene expression with the physiological adaptation processes. In this context, gene families related to abscisic acid (ABA) signaling play a crucial role in developmental and environmental adaptation processes of plants to drought stress. However, the families that function as the core components of ABA signaling, as well as genes networks related to drought response, are not well understood in castor bean. In this study 7 RcPYL, 63 RcPP2C, and 6 RcSnRK2 genes were identified in castor bean genome, which was further supported by chromosomal distribution, gene structure, evolutionary relationships, and conserved motif analyses. The castor bean general expression profile was investigated by RNAseq in root and leaf tissues in response to drought stress. These analyses allowed the identification of genes differentially expressed, including genes from the ABA signaling core, genes related to photosynthesis, cell wall, energy transduction, antioxidant response, and transcription factors. These analyses provide new insights into the core components of ABA signaling in castor bean, allow the identification of several molecular responses associated with the high physiological adaptation of castor bean to drought stress, and contribute to the identification of candidate genes for genetic improvement.
Asunto(s)
Ricinus communis , Ricinus communis/genética , Ricinus communis/metabolismo , Ricinus/genética , Ricinus/metabolismo , Redes Reguladoras de Genes , Sequías , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Transcriptoma , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ácido Abscísico/metabolismoRESUMEN
The objective of this work was to characterize 203 lineages and five parents of Ricinus communis L. from the germplasm bank at the Federal University of Recôncavo da Bahia (UFRB), which was established by the Genetic Improvement and Biotechnology Program (NBIO) at the Center for Agrarian, Environmental and Biological Sciences. The study used 35 morpho-agronomic descriptors, proposed by the Ministry of Agriculture, Livestock and Supply, and 12 quantitative descriptors suggested by NBIO. The experiment was conducted in a randomized block design, composed of four blocks, in the experimental field at UFRB in 2014. The frequency and entropy level of the qualitative descriptors were estimated with the Renyi procedure, and an analysis of variance was used for the quantitative descriptors. The analyses were made with the statistical program R. Of the qualitative morpho-agronomic descriptors evaluated, 22.86% had a high level of entropy (above 1.0), and all 12 quantitative descriptors showed significant differences. This indicates genetic variability in the germplasm bank and a satisfactory performance for most of the descriptors evaluated, as well as the possibility of direct and indirect use of the lineages and parents in genetic improvement programs of the species.
Asunto(s)
Ricinus communis/anatomía & histología , Ricinus communis/genética , Brasil , Ricinus communis/clasificación , Producción de Cultivos , Variación Genética , Fenotipo , Fitomejoramiento , Banco de SemillasRESUMEN
Ricin is a highly toxic ribosome-inactivating lectin occurring in the seeds of castor bean (Ricinus communis L.). Castor bean grows throughout tropical and sub-tropical regions and is a very important crop due to its high seed content of ricinoleic acid, an unusual fatty acid, which has several industrial applications. However, due to the presence of the toxin, castor bean can cause death after the exposure of animals to low doses of ricin through skin contact, injection, inhalation or oral routes. Aiming to generate a detoxified genotype, we explored the RNAi concept in order to silence the ricin coding genes in the endosperm of castor bean seeds. Results indicated that ricin genes were effectively silenced in genetically modified (GM) plants, and ricin proteins were not detected by ELISA. Hemagglutination activity was not observed with proteins isolated from GM seeds. In addition, we demonstrated that seed proteins from GM plants were not toxic to rat intestine epithelial cells or to Swiss Webster mice. After oil extraction, bio-detoxified castor bean cake, which is very rich in valuable proteins, can be used for animal feeding. Gene silencing would make castor bean cultivation safer for farmers, industrial workers and society.
Asunto(s)
Plantas Modificadas Genéticamente , Ricina/genética , Ricina/metabolismo , Ricina/toxicidad , Ricinus communis , Semillas , Animales , Ricinus communis/genética , Ricinus communis/metabolismo , Ratones , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Ratas , Semillas/genética , Semillas/metabolismoRESUMEN
Castor bean (Ricinus communis L.) is a tropical plant of great commercial interest and a potential source of biodiesel. The development of genetically improved cultivars with high amounts of oil in the seeds and low ricin toxicity is crucial to increase the productivity of this crop. The use of TRAP (target region amplification polymorphism) markers to develop elite lineages and study genetic divergence is fundamental to advance the genetic improvement of this species. The goal of this study was to evaluate the genetic divergence among 40 elite lineages of R. communis, which belong to the NBIO-UFRB Genetic Improvement Program, using TRAP markers involved in the biosynthesis of oil and ricin. Total DNA was extracted and quantified from the leaf tissue of the castor bean plants, and 70 TRAP combinations (fixed and arbitrary primers) were used to genotype the 40 lineages. Of the 580 fragments amplified, 335 were polymorphic (58%). The genetic dissimilarity among the lineages was calculated by the Jaccard dissimilarity index using the UPGMA grouping method. A dendrogram was generated, and four groups formed, showing divergence among the elite lineages that favors selection. The TRAP molecular markers were efficient at characterizing the genetic variability among the lineages and, because TRAP markers are functional markers involved in the biosynthesis of oil and ricin, they are important when studying the association between a marker and a candidate gene.
Asunto(s)
Evolución Molecular , Polimorfismo Genético , Ricinus communis/genética , Modelos GenéticosRESUMEN
Current demands for the genetic breeding of castor bean include the adaptation of genotypes to low altitudes to expand the potential areas of cultivation. This study was conducted to evaluate the response of different genotypes of castor bean that were sown in winter and summer at a low altitude. The study was conducted in northwestern Rio de Janeiro State at an altitude of 60 m. The treatments consisted of genotypes IAC 80, AL Guarany 2002, BRS 149 Nordestina, BRS 188 Paraguaçu, Savana, Lyra, Mirante 10, IAC 226, Cafelista, G1, V1, and T1 with spaces of 2.0 m between rows, 1.0 m between plants, and one plant per hole. The plant height, number and length of racemes, number of fruits per raceme, seed yield, and incidence of gray mold were determined. The highest yields in both seasons were obtained by the genotypes BRS 149 Nordestina, G1, BRS 188 Paraguaçu, and IAC 226. The genotypes Savannah and Lyra had the lowest yields in both cultivation seasons. The genotypes responded differently to the environmental conditions depending on the growing season, and the spring-summer period was found to be more favorable at the low altitude of the study site.
Asunto(s)
Altitud , Interacción Gen-Ambiente , Ricinus communis/genética , Estaciones del Año , Biomasa , Brasil , Ricinus communis/crecimiento & desarrollo , Ecología/métodos , Ecosistema , Genotipo , Geografía , Humedad , Lluvia , TemperaturaRESUMEN
PREMISE OF THE STUDY: Microsatellite primers were developed for Jatropha curcas (Euphorbiaceae), a tree species with large potential for biofuel production, to investigate its natural genetic diversity and mating system to facilitate the establishment of tree improvement and conservation programs. METHODS AND RESULTS: Using a protocol for genomic library enrichment, 104 clones containing 195 repeat motifs were identified. Primer pairs were developed for 40 microsatellite loci and validated in 41 accessions of J. curcas from six provenances. Nine loci were polymorphic revealing from two to eight alleles per locus, and six primers were able to amplify alleles in the congeners J. podagrica, J. pohliana, and J. gossypifolia, but not in other Euphorbiaceae species, such as Hevea brasiliensis, Manihot esculenta, or Ricinus communis. CONCLUSIONS: The primers developed here revealed polymorphic loci that are suitable for genetic diversity and structure, mating system, and gene flow studies in J. curcas, and some congeners.
Asunto(s)
Cartilla de ADN/genética , Jatropha/genética , Repeticiones de Microsatélite/genética , Hojas de la Planta/genética , Alelos , Ricinus communis/genética , ADN de Plantas/química , ADN de Plantas/genética , Variación Genética , Genotipo , Hevea/genética , Jatropha/clasificación , Manihot/genética , Datos de Secuencia Molecular , Polimorfismo Genético , Análisis de Secuencia de ADN , Especificidad de la EspecieRESUMEN
In this study, we performed a proteomic analysis of nucellus from two developmental stages of Ricinus communis seeds by a GeLC-MS/MS approach, using of a high resolution orbitrap mass spectrometer, which resulted in the identification of a total of 766 proteins that were grouped into 553 protein groups. The distribution of the identified proteins in stages III and IV into different Gene Ontology categories was similar, with a remarkable abundance of proteins associated with the protein synthesis machinery of cells, as well as several classes of proteins involved in protein degradation, particularly of peptidases associated with programmed cell death. Consistent with the role of the nucellus in mediating nutrient transfer from maternal tissues to the endosperm and embryo, a significant proportion of the identified proteins are related to amino acid metabolism, but none of the identified proteins are known to have a role as storage proteins. Moreover for the first time, ricin isoforms were identified in tissues other than seed endosperm. Results are discussed in the context of the spatial and temporal distribution of the identified proteins within the nucellar cell layers.
Asunto(s)
Proteínas de Plantas/metabolismo , Ricinus communis/crecimiento & desarrollo , Semillas/crecimiento & desarrollo , Apoptosis/fisiología , Ricinus communis/genética , Proteómica , Ricina/metabolismo , Semillas/químicaRESUMEN
The increasing need for renewable energy resources has led to higher demands for biofuel, a scenario where the castor bean (Ricinus communis L.) seed oil represents a promising source of raw material. Despite that, information regarding the genome organization of R. communis is still scarce, impairing the application of modern biotechnological and breeding procedures. The present work brings the first evaluation of the mitotic chromosomes of this species, including 10 potentially interesting accessions for cultivation in semi-arid environments aiming at the biofuel production. The approach included standard staining, fluorochrome staining (CMA/DAPI), fluorescent in situ hybridization (FISH) with rDNA 5S and 45S, as well as silver impregnation. All accessions were diploid with 2n=2x=20, displaying mainly metacentric chromosomes, with CMA-positive bands (GC-rich) in all pairs of the complement. After silver impregnation, one to 14 nucleoli were observed, while the FISH with rDNA 45S revealed two large sites and a variety of minor dots, and the DNAr 5S hybridized in a single pair. The observed features were discussed and compared with literature data regarding pachytene bivalents.