Castor bean (Ricinus communis L.) is an important oil crop, which belongs to the Euphorbiaceae family. The seed oil of castor bean is currently the only commercial source of ricinoleic acid that can ...be used for producing about 2000 industrial products. However, it remains largely unknown regarding the origin, domestication, and the genetic basis of key traits of castor bean.
Here we perform a de novo chromosome-level genome assembly of the wild progenitor of castor bean. By resequencing and analyzing 505 worldwide accessions, we reveal that the accessions from East Africa are the extant wild progenitors of castor bean, and the domestication occurs ~ 3200 years ago. We demonstrate that significant genetic differentiation between wild populations in Kenya and Ethiopia is associated with past climate fluctuation in the Turkana depression ~ 7000 years ago. This dramatic change in climate may have caused the genetic bottleneck in wild castor bean populations. By a genome-wide association study, combined with quantitative trait locus analysis, we identify important candidate genes associated with plant architecture and seed size.
This study provides novel insights of domestication and genome evolution of castor bean, which facilitates genomics-based breeding of this important oilseed crop and potentially other tree-like crops in future.
We have previously reported that Ricinus communis (castor) is more tolerant to soil cadmium (Cd) and more efficient for Cd phytoremediation than Brassica juncea (Indian mustard) (Bauddh and Singh, ...2012). In the present study, R. communis was found more tolerant to salinity and drought in presence of Cd and removed more Cd in a given time than Indian mustard. R. communis produced 23 and twelve folds higher biomass in terms of fresh weight and dry weight, respectively than that in B. juncea during three months when grown in Cd contaminated soil in presence of 100mM NaCl salinity and ten day water withdrawal based drought at 90 day after sowing (DAS). Castor plants showed stronger self-protection ability in form of proline bioaccumulation (r2=0.949) than Indian mustard (r2=0.932), whereas a lower r2 for malondialdehyde (MDA) and total soluble protein in R. communis (r2=0.914 and r2=0.915, respectively) than that of B. juncea (r2=0.947 and r2=0.927, respectively) indicated a greater damage to cell membrane in Indian mustard during the multiple stress conditions. Though, the amount of Cd accumulated in the roots and shoots of Indian mustard was higher as per unit biomass than that in castor, total removal of the metal from soil was much higher in castor on per plant basis in the same period in presence of the stresses. R. communis accumulated about seventeen and 1.5 fold higher Cd in their roots and shoots, respectively than that of B. juncea in 90 DAS under the multiple stresses. Salinity alone enhanced Cd uptake, whereas drought stress reduced its uptake in both the plants.
► The removal of Cd by B. juncea and R. communis in the presence of salinity and drought is reported. ► R. communis, an oil producing shrub, is found significantly tolerant to Cd, salinity and drought. ► R. communis extracted Cd rapidly from the soil as compared with well known phytoremediator B. juncea. ► B. juncea is more sensitive to these stresses than R. communis.
In plants, trehalose 6‐phosphate (T6P) is a key signaling metabolite that functions as both a signal and negative feedback regulator of sucrose levels. The mode of action by which T6P senses and ...regulates sucrose is not fully understood. Here, we demonstrate that the sucrolytic activity of RcSUS1, the dominant sucrose synthase isozyme expressed in developing castor beans, is allosterically inhibited by T6P. The feedback inhibition of SUS by T6P may contribute to the control of sink strength and sucrolytic flux in heterotrophic plant tissues.
The current study aims to evaluate the performance and emission characteristics of a modified common rail direct injection (CRDI) diesel engine fueled by Ricinus communis biodiesel (RCME20), diesel ...(80%), and their blends with strontium-zinc oxide (Sr@ZnO) nanoparticle additives. The Sr@ZnO nanoparticles were synthesized using aqueous precipitation of zinc acetate dehydrate and strontium nitrate. Several characterization tests were performed to study the morphology and content of synthesized Sr@ZnO nanoparticles. The Sr@ZnO nanoparticles were steadily blended with RCME20-diesel fuel blend in mass fractions of 30, 60 and 90 ppm using a magnetic stirrer and ultrasonication process. For a long term stability of nanoparticles, Cetyl trimethylammonium bromide (CTAB) surfactant was added. The physicochemical properties of the fuel blends were measured using ASTM standards. The CRDI engine was operated at two compression ratios 17.5 and 19.5, 1000 bar injection pressure, 23.5°BTDC injection timing and constant speed. For enhanced swirl and turbulence, and improved spray quality lateral swirl combustion chamber and 6-hole fuel injector were used. The compression ratio of 19.5 and 60 ppm of Sr@ZnO nano-additives showed overall enhancement in engine characteristics compared to RCME20 fuel. The engine characteristics such as BTE, HRR and cylinder pressure increased by 20.83%, 24.35% and 9.55%, and BSFC, ID, CD, smoke, CO, HC and CO2 reduced by 20.07%, 20.64%, 14.5%, 27.90%, 47.63%, 26.81%, and 34.9%, while slight increase in NOx for all nanofuel blends was observed.
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.
Papain-like cysteine proteases (PLCPs) are a class of proteolytic enzymes involved in many plant processes. Compared with the extensive research in Arabidopsis thaliana, little is known in castor ...bean (Ricinus communis) and physic nut (Jatropha curcas), two Euphorbiaceous plants without any recent whole-genome duplication. In this study, a total of 26 or 23 PLCP genes were identified from the genomes of castor bean and physic nut respectively, which can be divided into nine subfamilies based on the phylogenetic analysis: RD21, CEP, XCP, XBCP3, THI, SAG12, RD19, ALP and CTB. Although most of them harbor orthologs in Arabidopsis, several members in subfamilies RD21, CEP, XBCP3 and SAG12 form new groups or subgroups as observed in other species, suggesting specific gene loss occurred in Arabidopsis. Recent gene duplicates were also identified in these two species, but they are limited to the SAG12 subfamily and were all derived from local duplication. Expression profiling revealed diverse patterns of different family members over various tissues. Furthermore, the evolution characteristics of PLCP genes were also compared and discussed. Our findings provide a useful reference to characterize PLCP genes and investigate the family evolution in Euphorbiaceae and species beyond.
Genomic imprinting refers to parent-of-origin-dependent gene expression and primarily occurs in the endosperm of flowering plants, but its functions and epigenetic mechanisms remain to be elucidated ...in eudicots. Castor bean, a eudicot with large and persistent endosperm, provides an excellent system for studying the imprinting. Here, we identified 131 imprinted genes in developing endosperms and endosperm at seed germination phase of castor bean, involving into the endosperm development, accumulation of storage compounds and specially seed germination. Our results showed that the transcriptional repression of maternal allele of DNA METHYLTRANSFERASE 1 (MET1) may be required for maternal genome demethylation in the endosperm. DNA methylation analysis showed that only a small fraction of imprinted genes was associated with allele-specific DNA methylation, and most of them were closely associated with constitutively unmethylated regions (UMRs), suggesting a limited role for DNA methylation in controlling genomic imprinting. Instead, histone modifications can be asymmetrically deposited in maternal and paternal genomes in a DNA methylation-independent manner to control expression of most imprinted genes. These results expanded our understanding of the occurrence and biological functions of imprinted genes and showed the evolutionary flexibility of the imprinting machinery and mechanisms in plants.
Genomic imprinting often results in parent-of-origin specific differential expression of maternally and paternally inherited alleles. In plants, the triploid endosperm is where gene imprinting occurs ...most often, but aside from studies on Arabidopsis, little is known about gene imprinting in dicotyledons. In this study, we inspected genomic imprinting in castor bean (Ricinus communis) endosperm, which persists throughout seed development. After mapping out the polymorphic SNP loci between accessions ZB306 and ZB107, we generated deep sequencing RNA profiles of F1 hybrid seeds derived from reciprocal crosses. Using polymorphic SNP sites to quantify allele-specific expression levels, we identified 209 genes in reciprocal endosperms with potential parent-of-origin specific expression, including 200 maternally expressed genes and 9 paternally expressed genes. In total, 57 of the imprinted genes were validated via reverse transcriptase-polymerase chain reaction sequencing, and analysis of the genomic DNA methylation distribution between embryo and endosperm tissues showed significant hypomethylation in the endosperm and an enrichment of differentially methylated regions around the identified genes. Curiously, the expression of the imprinted genes was not tightly linked to DNA methylation. These results largely extended gene imprinting information existing in plants, providing potential directions for further research in gene imprinting.
Intensive production and commercialization of biodiesel from edible-grade sources have raised some critical environmental concerns. In order to mitigate these environmental consequences, alternative ...oilseeds are being investigated as biodiesel feedstocks. Castor (
Ricinus communis L.) is one of the most promising non-edible oil crops, due to its high annual seed production and yield, and since it can be grown on marginal land and in semi-arid climate. Still, few studies are available regarding its fuel-related properties in its pure form or as a blend with petrodiesel, many of which are due to its extremely high content of ricinoleic acid. In this study, the specifications in ASTM D6751 and D7467 which are related to the fatty acid composition of pure castor methyl esters (B100) and its blend with petrodiesel in a 10% vol ratio (B10) were investigated. Kinematic viscosity and distillation temperature of B100 (15.17 mm
2 s
−1 and 398.7 °C respectively) were the only two properties which did not meet the appropriate standard limits. In contrast, B10 met all the specifications. Still, ASTM D7467 requires that the pure biodiesel meets the requirements of ASTM D6751. This can limit the use of a wide range of feedstocks, including castor, as alternative fuel, especially due to the fact that in practice vehicles normally use low level blends of biodiesel and petrodiesel. These issues are discussed in depth in the present study.
► CaME can be used as a biodiesel alternative feedstock when blended in petrodiesel. ► Due to the high levels of ricinoleic acid maximum blending level is limited to 10%. ► Today, CaME blends are not a viable alternative feedstock. ► ASTM D7467 requires that pure biodiesel must meet all the appropriate limits.
We studied chelate effects on castor bean (Ricinus communis L.) growth. These effects included Cd and Pb accumulation in plant tissues and the chemical behavior of Cd and Pb in the plant rhizosphere ...and non-rhizosphere. Tests were conducted in a glasshouse using the rhizobag method. Two castor bean cultivars (Zibo-3 and Zibo-9) were grown in soil contaminated with 3.53mg/kg Cd and 274mg/kg Pb. The soil was treated with citric acid (CA), ethylenediamine disuccinic acid (EDDS) or ethylenediamine tetraacetic acid (EDTA) (5mmol/kg). EDDS-treated soil produced 28.8% and 59.4% greater biomass for Zibo-3 and Zibo-9 respectively. In contrast, CA and EDTA inhibited the growth of the two cultivars. Zibo-9 had greater tolerance than Zibo-3 to chelate toxicity. Based on Cd and Pb plant uptake, EDDS could substitute for EDTA for phytoremediation of Cd in soil. EDTA was the most effective of the three chelates for Pb phytoremediation but it is less suitable for field use due to toxicology environmental persistence. Acid extractable Cd and Pb in the rhizosphere or reducible Cd and Pb in the non-rhizosphere of soil were the main influences on Cd and Pb accumulation in castor bean.
•EDDS-treated soil promoted the growth of two castor cultivars.•EDDS is a substitute for EDTA for enhancing castor phytoremediation of Cd polluted soil.•Acid extractable Cd and Pb in the soil rhizosphere or reducible Cd and Pb in the non-rhizosphere had the greatest influence on Cd and Pb accumulation in castor tissues.
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