Draft genome sequence of the rubber tree Hevea brasiliensis 7thSpace Interactive (press release) Conclusions: The knowledge gained from this genome sequence will aid in the future development of high-yielding clones to keep up with the ever...
Yulex, partner seek to double guayule rubber yield Tire Business "We are excited to leverage the lessons learned with Jatropha (a species of flowering plant with an oil content said to be about 38 percent) and apply our proprietary genome-based...
Lutoids are specific vacuole-based organelles within the latex-producing laticifers in rubber tree Hevea brasiliensis. Primary and secondary lutoids are found in the primary and secondary laticifers, respectively. Although both lutoid types perform similar roles in rubber particle aggregation (RPA) and latex coagulation, they vary greatly at the morphological and proteomic levels. To compare the differential proteins and determine the shared proteins of the two lutoid types, a proteomic analysis of lutoid membranes and inclusions was performed, revealing 169 proteins that were functionally classified into 14 families. Biological function analysis revealed that most of the proteins are involved in pathogen defense, chitin catabolism, and proton transport. Comparison of the gene and protein changed patterns and determination of the specific roles of several main lutoid proteins, such as glucanase, hevamine and hevein, demonstrated that chitinase and glucanase appeared to play crucial synergistic roles in RPA. Integrative analysis revealed a protein-based metabolic network mediating pH and ion homeostasis, defense response, and RPA in lutoids. From these findings, we developed a modified regulation model for lutoid-mediated RPA that will deepen our understanding of potential mechanisms involved in lutoid-mediated RPA and consequent latex coagulation.
Effect of Lethal Concentrations of Rubber Extract (Hevea brasiliensis) on the Survival on Fingerlings of Clarias gariepinus under Laboratory Condition.
Biswapriya Biswavas Misra's insight:
The water soluble fraction (WSF) of Hevea brasiliensis was tested against Clarias garienpinus, at 0, 30, 40, 50, 60 and 70mg/l in glass aquaria stocked with ten animals for 96 hours under observation for changes. Moribund swimming, restlessness, respiratory difficulties, depigmentation and mortalities were observed in the WSF exposure groups, but not in the controls. LC50 values were estimated at 50.12mg/l. There was no significant difference in mortalities between the replicate group (P>0.05), leading to the conclusion that the WSF of Hevea brasiliensis had same toxic effects on both batches of the test organism.
Microcyclus ulei, the fungus causing South American Leaf Blight (SALB) on rubber tree leaves, produces two main types of spores: ascospores and conidia. To assess their respective epidemiological role, a field experiment was conducted in French Guiana over three years. Tree phenology, disease severity and climate variables were recorded, while airborne spores were trapped and quantified. Ascospores were shown to play an essential role in the perpetuation of the disease outside the host's growth periods, in the resumption of epidemics, and in the spread of the disease to disease-free zones. Conidia were trapped in visibly infected plots only, during periods of host growth. Disseminated over short distances and present only temporarily on leaves, the conidia enabled the disease to spread stepwise when the climate was conducive. Segmentation analysis revealed that the duration of high relative humidity was the climatic variable most related to ascospore trapping. Ascospore release did not require low temperatures. Considering the essential role of the ascospores in the initiation and spread of disease, artificial defoliation as a means of reducing the inoculum pressure during tree refoliation is proposed to control SALB. To check the availability of this method, a several years-survey of natural defoliation-refoliation in relation to climate and other leaf diseases is needed.
Biodiesel is a fast emerging alternate fuel but with its own disadvantage of having limited oxidative stability.
Biswapriya Biswavas Misra's insight:
Biodiesel is a fast emerging alternate fuel but with its own disadvantage of having limited oxidative stability. Fatty acid methyl esters (FAMEs) obtained from high acid value (46.41 mgKOHg-1) rubber seed oil (RSO) was characterized by GC-MS and 1H-NMR. Fuel properties analysed were found to fit the required ASTM D6751 standard. Moreover, the possibility of monitoring the conversion efficiency of RSO to its corresponding methyl esters using FT-IR and NIR techniques was also analysed. As an important specification of bio-fuel quality, the fuel must have a minimum of three hours of oxidative stability (110°C) as per ASTM D6751 standard. Influence of metal contaminants, air, moisture and light on oxidative stability was studied on biodiesel having high iodine value. Acid value, peroxide value and induction period were recorded for samples under six different environments such as open (light exposed), closed (light exposed), open (dark), closed (dark), open (metal contaminated) and closed with metal contamination. Significant impact was observed only when metals are present as contaminants. Extent of degradation (oxidation) is higher when the samples are contaminated by metals, limiting the storage stability to thirty days. Higher oxidative stability was achieved under dark in the closed environment but in the absence of any metal contaminant.
Leafspot of Hevea brasiliensis caused by Corynespora cassiicola in the Philippines: 1st report
Biswapriya Biswavas Misra's insight:
This is the first report of the incidence or occurrence of a leafspot or leaf fall disease caused by Corynespora cassiicola (Berk. and Curt.) Wei affecting rubber (Hevea brasiliensis) in this country. The disease was first observed by the authorresearchers in RRIM 600 rubber seedlings and young trees at USMARC nurseries and plantations sometime in October 2008. Standard laboratory procedures were done: fresh specimens of infected rubber leaves were collected, thin sections of the infected tissues made, and direct examinations on slide mounts observed under a compound microscope. Morphocultural characteristics of the fungus were noted through microscopy and the fungal growth observed on various culture media. Pathogenicity tests were confirmed by inoculating healthy Hevea seedlings. Identity was confirmed through literatures.
Construction of Hevea brasiliensis Genetic Linkage Map and Identification of Quantitative Trait Loci Using RAPD Markers
Biswapriya Biswavas Misra's insight:
Rubber breeding program so far have constraints especially in selection process which need very wide area and very long time. The use molecular markers in breeding program could simplify the selection procedure. The objectives of research were to get the linkage map especially for PB 260 as female parent, and to get RAPD markers and morphology markers which associated with QTL controlling production component. Construction of genetic linkage map on rubber tree (2n=36) was conducted by using RAPD markers data through pseudo-testcross. First generation progenies of crossing between PB 260 and PN were used as mapping populations: 22 progenies of A population (PB 260 x PN 7111), 20 progenies of C population (PB 260 x PN7). Construction of linkage map was conducted using MAPMAKER/EXP 3.0. Linkage map of PB 260 was constructed on LOD 3.0 yielded 1 linkage group, on LOD 2.5 yielded 2 linkage group. Based on single marker analysis through t-test was known that marker C13-2000 linked with yield character and number of latex vessel character. Character of leaf shape linked with girth, bark thickness, and number of latex vessel. Character of leaf edge linked with plugging index.
Wood characteristics vary from pith to bark and this can influence the final use. These variations can be related to the effects of plantation management. The radial variation in fiber cells, vessel elements, and ray cells was investigated for a commercial and fast-grown species, the rubberwood (Hevea brasiliensis), at varying stocking densities. Nine-year-old trees of two new clones (RRIM 2020 and RRIM 2025) were categorized into four stocking densities of 500, 1000, 1500, and 2000 trees ha−1. The sample blocks were anatomically analyzed to determine the changes in wood cells from pith to bark. The results generally showed a centrifugal increase in fiber features, vessel diameter, ray height, and ray area. Vessel density and ray density showed a decreasing trend. Vessel areas revealed a radial irregular variation. The ray area showed a striking relationship with ray density and ray height. Ray cell pattern indicated enough variation for visual approval to ensure within and between stocking density changes. Most radial variation was explained by the effect of cambial age. Owing to different stem width and growth rates, the mean cell features were not at the same radial distances from the pith.
Yulex, SGB collaborate on genomics platform RubberNews.com SGB's work on guayule will combine breeding and germplasm selection with genomic technologies, including high-throughout genotyping, genome-wide trait association studies, genomic selection...
Global Natural-Rubber Consumption Growth Seen Reducing Surplus Bloomberg World natural-rubber consumption is set to increases this year and the next, reducing a glut and boosting prices of the commodity used in tires, according to The Rubber...
A Laboratory Bioassay of the Potential Effect of Rubber Extract (Hevea brasiliensis) on the Survival of Fingerlings of Oreochromis niloticus
Biswapriya Biswavas Misra's insight:
The potential effects of Hevea brasiliensis on the survival of fingerlings of Oreochromis niloticus were investigated in duplicate (A and B) using the water soluble fraction of the latex under laboratory conditions for 96 hours. The WSF of Hevea brasiliensis was tested against Oreochromis niloticus at 0, 8, 16, 24, 32 and 40mg/l in glass aquaria stocked with ten animals for 96 hours under observation for changes. Behavioural pattern exhibited by the fish include, loss of balance, restlessness, attempt at jumping out and hemorrhaged gills, respiratory difficulties and mortalities were observed in the WSF exposure groups, but not in the controls. LC50 values were estimated at 28. 50 ± 0.2mg/l. There was significant difference in mortalities between the replicate group (p < 0.05), leading to conclusion that the organism in each batch responded differently to the toxic effect of WSF of Hevea brasiliensis latex.
Farming management practices related to nutrient recommendation for rubber tree plantations have been a challenge for scientists, farm managers and local producers. Specific caves and building contour ledges to prevent nutrient losses through soil erosion often cause spatial variation of topsoil nutrients in such plantations of rubber trees (Hevea brasiliensis). The design of soil-sampling schemes to test chemical properties of the soil is critical for successful nutrient recommendation for rubber trees. Our objectives were to characterize the spatia variability of soil pH, macronutrient NPK and organic matter in rubber plantations and to evaluate the rationality of soil sampling schemes in rubber plantations for tree nutrient management. The study was conducted in an area of 84 m2 consistent of nine rubber trees and soil samples (0–0.2 m depth) were taken from 168 grid points with a dimension of 1 m × 0.5 m. Concentrations of total nitrogen, organic matter, available phosphorus, available potassium and pH levels were determined for each soil sample. Based on their spatial variability patterns, the analyzed variables were divided into several homogeneous zones through fuzzy cluster algorithm. The number of subzones was determined using fuzzy performance index and normalized classification entropy to optimize the classification algorithm. The classification results showed that there were three optimal sampling zones for the soil chemical properties. The analysis of variance indicated that chemical properties were significantly different between the delineated zones. The delineated management zones could be used as a reference for making soil-sampling scheme in the rubber plantation. The results of this study have the implication in optimization of soil sampling planning for soil testing for nutrient recommendation. Fuzzy cluster algorithms could classify soil chemical properties into three practical zones by reducing intrazone variability, which would provide with useful information for making effective soil-sampling schemes in rubber tree plantations.
A laticiferous tissue-specific SRPP (small rubber particle-associated protein) promoter derived from Hevea brasiliensis, consists of nucleotide sequence of SEQ ID NO: 1. A recombinant plant exp
Biswapriya Biswavas Misra's insight:
A laticiferous tissue-specific SRPP (small rubber particle-associated protein) promoter derived from Hevea brasiliensis, consists of nucleotide sequence of SEQ ID NO: 1. A recombinant plant expression vector includes the promoter. A plant is transformed with the recombinant plant expression vector and seed of the transformed plant is obtained. A method for laticiferous tissue-specific expression of a foreign gene in a transformed plant includes performing recombination of a foreign gene into the recombinant plant expression vector. The transformed plant produced by the method shows laticiferous tissue-specific expression of a foreign gene.
The objective of this research was to apply short wave near infrared (NIR) (700–1100 nm) spectroscopy to the evaluation of dry rubber content (DRC, %) and total solids content (TSC, %) in Para rubber field and concentrated latex. The spectra were obtained in transmission mode. There were 282 samples including field latex, concentrated latex and concentration adjusted concentrated latex of 171, 86 and 25 samples, respectively. The field latex had around 30% DRC and the concentrated latex had around 60% DRC. The concentration adjusted concentrated latex was in five levels which were 55%, 50%, 45%, 40% and 35% DRC. The calibration models were developed by original and pretreated absorbance spectra using partial least square regression (PLSR). The pretreatment methods were smoothing, normalization, derivative, baseline offset, standard normal variate (SNV) or multiple scatter correction (MSC). By statistical analysis, the model developed from smoothing and range normalization pretreated spectra in the wavelength range of 700–950 nm provided the best accuracy of prediction for DRC and the models usingfrom raw spectra in the same wavelength range gave the best results for TSC. The slope, offset, coefficient of determination (r2), standard error of prediction (SEP) and bias were 1.0154, -0.6286, 0.992, 1.1092% and 0.0321%, respectively for the prediction of DRC and 1.0084, –0.2332, 0.991, 1.3611% and 0.1456%, respectively for the prediction of TSC. The best models were validated using new sets of 50 and 35 unknown samples for DRC and TSC, respectively. The models achieved in r2 of 0.988 and 0.974, SEP of 1.4296 and 2.1255, RDP of 9.978710.0 and 6.1728 and bias of –0.6191% and 0.5476% for DRC and TSC, respectively. This work showed the high accuracy of shortwave near infrared spectroscopy in evaluation of TSC, the essential parameter for quality assurance and process control in the concentrated rubber latex factory. However, the accuracy for prediction of DRC was still not acceptable for the latex factory because a bias of more than 0.01% is not acceptable for it would affect the amount of money which the factory may loose or gain.
Small rubber particle protein (SRPP) is a major component of Hevea brasiliensis (H. brasiliensis) latex, which is involved in natural rubber (NR) biosynthesis. However, little information is available on the regulation of SRPP gene (HbSRPP) expression. To study the transcriptional regulation of HbSRPP, the yeast one-hybrid experiment was performed to screen the latex cDNA library using the HbSRPP promoter as bait. One cDNA that encodes the WRKY transcription factor, designated as HbWRKY1, was isolated from H. brasiliensis. HbWRKY1 contains a 1437 bp open reading frame that encodes 478 amino acids. The deduced HbWRKY1 protein was predicted to possess two conserved WRKY domains and a C2H2 zinc-finger motif. HbWRKY1 was expressed at different levels, with the highest transcription in the flower, followed by the bark, latex, and leaf. Furthermore, the co-expression of pHbSRP::GUS with CaMV35S::HbWRKY1 significantly decreased the GUS activity in transgenic tobacco, indicating that HbWRKY1 significantly suppressed the HbSRPP promoter. These results suggested that HbWRKY1 maybe a negative transcription regulator of HbSRPP involved in NR biosynthesis in H. brasiliensis.
Plantlets were obtained by culture of unpolinated ovules of rubber tree, Hevea brasiliensis. The ovules were cultured on a dedifferentiation medium, and later transfered to a differentiation medium. Cytological observations indicated that the plantlets tested were mixaploids.
This study was aimed at evaluating the properties of juvenile and mature wood from Hevea brasiliensis untapped and with tapping panels. Boards were taken from a 53-year-old Hevea brasiliensis plantation located in Tabapuã, São Paulo, Brazil. Half of the boards had the tapping panels region, and the other half had the untapped region. The results showed that: (1) there were increases of 6.6 % in the volumetric shrinkage of mature wood when compared with juvenile wood; (2) the densities and chemical properties of juvenile and mature woods are statistically equal; and (3) the tapping panel does not influence the properties of rubberwood.
The importance of the rubber yield from the rubber tree (Hevea brasiliensis) is already well known. Recently, the importance of girth growth and consequently wood rubber tree has been emphasized. Genotypes with greater girth growth produce greater volume of wood. Rubber tree timber can be used as raw material for a vast range of products, substituting wood from natural forests. Rubber tree genotypes that combine high yield and vigorous growth are of great interest for genetic improvement. Thus, the objective of the present study is the simultaneous selection in young rubber tree progenies for dual-purpose rubber yield and girth growth. Twenty-two progenies were used which were assessed at the field in two locations in a randomized experimental block design with three replicates and 3 m × 3 m spacing. The classic selection index was used; this index is a tool that allows all the characters of interest to be used simultaneously. The progeny effect was significant for both variables and in both locations, indicating progeny genetic variability and the possibility of selection. The progeny mean heritability (hˆx¯2) was greater than the heritability based on single individual's level (hˆi2) and within plot heritability (hˆw2). The multicollinearity among the variables was low, so the variables could be used simultaneously to construct the selection index. Four progenies were selected with an 18% selection intensity, but the progenies were different in the two locations. The classic selection index was efficient in simultaneous selection of rubber yield and girth growth in progeny of young rubber trees. Simultaneous selection for rubber yield and vigor is important at the initial stages of genetic breeding and should be done per location. This selection contributes to identifying superior progeny for rubber yield and with potential for double purpose: wood and rubber production.