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Mitochondrial/Cytosolic Acetyl CoA and Rubber Biosynthesi Genes Expression in Hevea brasiliensis Latex and Rubber Yield

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Pesquisa Agropecuária Brasileira - Genetic diversity of cultivated accessions and wild species of rubber tree using EST‑SSR markers

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ABSTRACT

The objective of this work was to evaluate the efficiency of EST‑SSR markers in the assessment of the genetic diversity of rubber tree genotypes (Hevea brasiliensis) and to verify the transferability of these markers for wild species of Hevea. Forty‑five rubber tree accessions from the Instituto Agronômico (Campinas, SP, Brazil) and six wild species were used. Information provided by modified Roger's genetic distance were used to analyze EST‑SSR data. UPGMA clustering divided the samples into two major groups with high genetic differentiation, while the software Structure distributed the 51 clones into eight groups. A parallel could be established between both clustering analyses. The 30 polymorphic EST‑SSRs showed from two to ten alleles and were efficient in amplifying the six wild species. Functional EST‑SSR microsatellites are efficient in evaluating the genetic diversity among rubber tree clones and can be used to translate the genetic differences among cultivars and to fingerprint closely related materials. The accessions from the Instituto Agronômico show high genetic diversity. The EST‑SSR markers, developed from Hevea brasiliensis, show transferability and are able to amplify other species of Hevea.

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Sciatic nerve regeneration in rats by a nerve ... [Acta Cir Bras. 2012] - PubMed - NCBI

Abstract

PURPOSE:

To evaluate the capacity of natural latex membrane to accelerate and improve the regeneration quality of the of rat sciatic nerves.

METHODS:

Forty male adult Wistar rats were used, anesthetized and operated to cut the sciatic nerve and receive an autograft or a conduit made with a membrane derived from natural latex (Hevea brasiliensis). Four or eight weeks after surgery, to investigate motor nerve recovery, we analyzed the neurological function by walking pattern (footprints analysis and computerized treadmill), electrophysiological evaluation and histological analysis of regenerated nerve (autologous nerve graft or tissue cables between the nerve stumps), and anterior tibial and gastrocnemius muscles.

RESULTS:

All functional and morphological analysis showed that the rats transplanted with latex conduit had a better neurological recovery than those operated with autologous nerve: quality of footprints, performance on treadmill (p<0.01), electrophysiological response (p<0.05), and quality of histological aspects on neural regeneration.

CONCLUSION:

The data reported showed behavioral and functional recovery in rats implanted with latex conduit for sciatic nerve repair, supporting a complete morphological and physiological regeneration of the nerve.

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MY2012000014 A METHOD FOR REGULATING BIOSYNTHESIS OF MONOLIGNOLS

MY2012000014 A METHOD FOR REGULATING BIOSYNTHESIS OF MONOLIGNOLS | Hevea brasiliensis | Scoop.it
(EN)A method for reducing the synthesis of monolignols in cytoplasm of the plant of Hevea brasiliensis, comprising the step of down-regulating expression of a nucleic acid template containing at least one nucleotide sequence set forth in SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4, SEQ ID NO. 5, SEQ ID NO. 6, SEQ ID NO. 7, SEQ ID NO. 8, SEQ ID NO. 9, SEQ ID NO. 10, SEQ ID NO. 1 1 or SEQ ID NO. 12 in at least one cell. Also claimed are nucleotide sequences encoding phenylalanine ammonia-lyase 1 (PALI), phenylalanine ammonia-lyase 2 (PAL2), cinnamate 4-hydroxylase (CH4), coumarate 3-hydroxylase 1 (C3H1), coumarate 3-hydroxylase 2 (C3H2), caffeic acid/5-hydroxyconiferaldehyde O-methyltransferase (COMT), Hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyl transferase (HCT), ferulate 5-hydroxylase (F5H), 4-coumarate CoA ligase (4CL), 4-coumarate caffeoyl-CoA O-methyltransferase (CCoAOMT), 4-coumarate cinnamoyl coenzyme A reductase (CCRl), and 4-coumarate cinnamyl alcohol dehydrogenase (CAD) enzymes, all from Hevea brasiliensis.
(FR)La présente invention a pour objet un procédé pour la réduction de la synthèse de monolignols dans le cytoplasme de la plante d'Hevea brasiliensis, comprenant l'étape de régulation à la baisse de l'expression d'une matrice d'acide nucléique contenant au moins une séquence de nucléotides présentée dans SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4, SEQ ID NO. 5, SEQ ID NO. 6, SEQ ID NO. 7, SEQ ID NO. 8, SEQ ID NO. 9, SEQ ID NO. 10, SEQ ID NO. 11 ou SEQ ID NO. 12 dans au moins une cellule. La présente invention concerne également des séquences de nucléotides codant les enzymes phénylalanine ammoniac-lyase 1 (PAL1), phénylalanine ammoniac-lyase 2 (PAL2), cinnamate 4-hydroxylase (CH4), coumarate 3-hydroxylase 1 (C3H1), coumarate 3-hydroxylase 2 (C3H2), acide caféique/5-hydroxyconiféraldéhyde O-méthyltransférase (COMT), hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyl transférase (HCT), férulate 5-hydroxylase (F5H), 4-coumarate CoA ligase (4CL), 4-coumarate cafféoyl-CoA O-méthyltransférase (CCoAOMT), 4-coumarate cinnamoyl coenzyme A réductase (CCRl), et 4-coumarate alcool cinnamylique déshydrogénase (CAD), toutes issues d'Hevea brasiliensis.

 

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Method for producing isoprenoid, isoprenoid, callus, method for inducing callus,... - IP.com

Abstract (English, WO 2012099100 A1)

Provided are: a method for stably producing an isoprenoid without relying on an adult tree of Hevea brasiliensis; and an isoprenoid which is obtained by the production method. Also provided are: a novel callus which is capable of producing an isoprenoid; a method for inducing the callus; and a method for culturing the callus. The present invention relates to: a method for producing an isoprenoid, wherein an isoprenoid is biosynthesized by means of a callus of an isoprenoid-producing plant; and an isoprenoid which is obtained by the production method. The present invention also relates to: a callus which is induced by culturing tissue fragments of an isoprenoid-producing plant in an induction medium that contains a plant growth hormone and a carbon source; a method for inducing a callus, wherein a callus is induced by culturing tissue fragments of an isoprenoid-producing plant in an induction medium that contains a plant growth hormone and a carbon source; and a method for culturing a callus, wherein a callus is grown by culturing a callus of an isoprenoid-producing plant in a growing medium that contains a plant growth hormone and a carbon source.

Patent Family Members (1; WO):

WO 2012099100 A1
application

Method for producing isoprenoid, isoprenoid, callus, method for inducing callus, and method for culturing callus (26-Jul-2012)
Applicants: SUMITOMO RUBBER INDUSTRIES, LTD., 住友ゴム工業株式会社, YAMAGATA UNIVERSITY, 国立大学法人山形大学, UESUGI Akari, 上杉 明里, HOSOKAWA Tomohiro, 細川 友宏, KURODA Satoshi, 黒田 智, INOUE Yukino, 井之上 ゆき乃, OHYA Norimasa, 大谷 典正

 

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Screening of rubber (Hevea brasiliensis Muell. Arg.) rootstocks for the white root disease resistance

Screening of rubber (Hevea brasiliensis Muell. Arg.) rootstocks for the white root disease resistance

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Breeding for Disease Resistance in Hevea spp. - Status, Potential Threats, and Possible Strategies

South America, has only been recently domesticated outside its natural range of distribution. Almost all of the commercially cultivated clones of H. brasiliensis represent a very narrow genetic base since they originated through hybridization or selection from a few seedlings of so called Wickham germplasm. Hence, the commercial rubber cultivation, due to their genetic vulnerability, is under a constant threat of attack by native as well as exotic diseases and insects. Climate change, which is clearly felt in the traditional rubber growing regions of India, may possibly alter the host-pathogen interactions leading to epidemics of otherwise minor diseases.
Pathogenic fungal diseases including Phytophthora-caused abnormal leaf fall (ALF) and shoot rot, pink disease caused by Corticium salmonicolor, Corynespora-caused leaf disease, and powdery-mildew (Oidium sp.) are challenging diseases posing epidemic threats to rubber cultivation. South American leaf blight (SALB) is a devastating disease caused by Microcyclus ulei (=Dothidella ulei) which has prevented large-scale planting of rubber in Brazil due to epidemic outbreaks. The SALB is a looming threat to other rubber growing areas. Hence, it is essential that a global SALB resistance breeding program be implemented to tackle such future threats of epidemics. Hevea clones clearly exhibit variable levels of susceptibility to pathogenic diseases. Hevea clones have been tested for their capacity to produce phytoalexins; a strong correlation was observed between phytoalexin accumulation and clone resistance. More lignin accumulation was also often associated with clone resistance. Attempts have been made to identify possible disease resistance gene analogues in rubber. The role of M13-1bn marker (a putative quantitative trait locus) in screening for resistance to SALB had been investigated through genome mapping, but needs further validation. Earlier selection and breeding of Hevea clones resistant to M. ulei and Phytophthora sp. in Brazil led to screening of resistant clones. Most of the resistant material had been derived from H. benthamiana “F4542.” Few other attempts for inter-specific hybridization have been made, particularly for SALB resistance (H. camargoana x FX 4098), but they did not follow large-scale evaluations for field resistance.
Many man hours of labor and enormous quantities of fungicidal chemicals are required every year for management of above diseases in vast areas of rubber plantations in India and other rubber growing countries. The cost of fungicides and their long-term effect on environment justify the need for breeding disease resistant trees. There are several theories for genetic basis for disease resistance (horizontal/vertical) in Hevea. Nevertheless, there is every possibility for breakdown of resistance due to ever-evolving pathogenic races coupled with climate change, which is exemplified by evolving SALB races. A multidisciplinary breeding program for development of disease resistant clones would have to continuously utilize Wickham resource as well as wild germplasm, in addition to other Hevea spp., in order to have sustainable rubber production.
Key words: Hevea brasiliensis, fungal diseases, South American leaf blight, Microcyclus ulei, disease resistance breeding

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Latex C-serum from Hevea brasiliensis induces non-apoptotic cell death in hepatocellular carcinoma cell line (HepG2) - Lam - 2012 - Cell Proliferation - Wiley Online Library

Latex C-serum from Hevea brasiliensis induces non-apoptotic cell death in hepatocellular carcinoma cell line (HepG2) - Lam - 2012 - Cell Proliferation - Wiley Online Library | Hevea brasiliensis | Scoop.it

Objectives

Latex from Hevea brasiliensis (natural rubber tree primarily cultivated for its rubber particles) has no known primary metabolic function, although its biological role is as a plant defence system. The present study has evaluated specific anti-proliferative effects of latex whole C-serum and its subfractions, on human cancer cell lines.

Materials and methods

Cell viability assay using MTT, DNA fragmentation assay and real-time PCR were used to evaluate the cytotoxic effects of latex whole C-serum and its subfractions on the cell lines.

Results

MTT assay revealed very low LC50 values, 2.0 and 280 ng/ml, for DCS and DCP treatments, respectively. DCS was proven to be more potent compared to DCP, in conferring specific anti-proliferative effects on the cancer cell lines. The study also indicated that anti-proliferative activity of pre-heated C-serum fractions diminished significantly.

Conclusion

Although noteworthy cell death was reported, DNA fragmentation assay and real-time PCR confirmed that that induced by latex C-serum subfractions was not promoted via the classical apoptotic signalling pathway.

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Influence of age and girth at opening on rubber yield, biochemical and tapping panel dryness parameters of Hevea brasiliensis in determining tapping norms

The incidence of several girths or tapping start period on the parameters of rubber yield, the physiological profile and the sensitivity to tapping panel dryness of Hevea brasiliensis have been studied for a decade in southeastern rubber growing area of Côte d'Ivoire. The study was conducted from so called early (tapping start at 40, 45 cm girth) and/or late (opening at 55, 60 and 65 cm girth) tapping applied to clones GT 1, PB 217 and PB 235. This study shows that starting tapping clone GT 1 at 40 cm girth and clones PB 217 and PB 235 at 50 cm are the best treatments in terms of rubber yield, physiological parameters and tapping panel dryness. These girths at the opening were reached at approximately 6 years after planting, regardless of the clone. The satisfactory results recorded demonstrate the preponderance of the notion of "opening age" over that of circumference of tapping start. Thus, the age of 6 years after planting seems to be the best period to start tapping rubber trees, because it is a good benchmark of physiological maturity in Hevea brasiliensis. Despite this precedence of the age over the girth, the different results indicate the need to use both criteria to take into account a delay in the growth and especially a difference in the vegetative growth of the clones planted.

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Yield and chemical properties of rubber of Hevea clones according to phenological stages

ABSTRACT

The objective of this work was to evaluate the yield performance and macronutrient content of rubber extracted from four Hevea brasiliensis clones, under different tapping systems and plant phenological stages. The experiment was carried out in the 2010 and 2011 crop seasons, in a split‑plot randomized complete block design, with four replicates. The main treatments – GT 1, PB 235, IAN 873, and RRIM 600 clones – were allocated in the plots, and the secondary treatments, which were the tapping systems &frac12;S d/2, &frac12;S d/4 ET 2.5%, and &frac12;S d/7 ET 2.5%, were allocated in the subplots. The analyzed variables were natural rubber yield and macronutrient contents. Samples of natural rubber were obtained in the leaf development, mature leaf, and leaf senescence phenological stages. Rubber yield and its macronutrient contents are more influenced by tapping practice than by genetic material in the restrictive phenological stages of foliage.

Index terms: Hevea brasiliensis, phenology, rubber nutrients, exploitation systems.

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THE β-GLUCAN FROM Hevea brasiliensis LATEX AND ITS POSSIBLE APPLICATION IN ANTI-AGING COSMECEUTICALS

β-glucans, a type of polysaccharide with repeating glucose monosaccharide units,
are primary components in cell walls of bacteria, fungi, yeasts, algae, some seaweeds, cereals
and higher plants. They are best known for their abilities to enhance immune system as
immune system modulating compounds. Moreover, β-glucans had also been shown to
support wound healing by promoting fibroblast migration into the wound, stimulating
fibroblast proliferation as well as increasing the production of fibroblast collagen.1,2 In this
study, we are interested in studying β-glucan from rubber latex collected after tapping panel
wounding (bark stripping) of the rubber tree (Hevea brasiliensis). The Hevea latex β-glucan
was extracted and purified from a solution prepared from spray dried rubber latex serum,
after protein removal with trichloroacetic acid treatment, by ethanol precipitation. The Hevea
latex β-glucan posseses molecular weight less than 8.2 kDa, assessed from LC/MS spectrum.
The FT-IR spectrum of Hevea β-glucan revealed O-C bond stretching of β-1,3-glucan at
wavenumber 1079.77 cm-1. By using MTT assay, the Hevea β-glucan was not only found to
be devoid of cytotoxicity but also able to stimulate fibroblast proliferation. Moreover, the
Hevea β-glucan at concentrations of 10, 20 and 30 μg/ml were found to increase fibroblast
collagen production, as compared to control, by 85, 121 and 158 %, respectively. These
results suggest possible application of the Hevea β-glucan for treatment involving collagen
loss in aging skin.

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Mitochondrial/Cytosolic Acetyl CoA and Rubber Biosynthesis Genes Expression in Hevea brasiliensis Latex and Rubber Yield

Expressions of the 22 genes involved in rubber biosynthesis, from the acetyl CoA genesis and
the mevalonate (MVA) pathway to IPP polymerization, were analyzed by real-time polymerase chain
reaction (PCR). The results revealed that the expressions of most genes were not related to the latex yield
trait when compared among three high- and three low-yielding rubber clones. Only the genes HMGR3
and SRPP1 were signifi cantly up-regulated in low-yielding clones. The higher expression of the SRPP1
gene in low-yielding clones suggested a possible increase in the number and higher rubber biosynthetic
activity of the active small rubber particles, which may produce latex with higher viscosity, impairing
the latex fl ow and limiting the latex yield. The up-regulation of the HMGR3 gene in low-yielding clones
may refl ect a higher amount or activity or both of Frey-Wyssling particles (plastids) in their latex. These
plastids have been shown to be involved in oxidative processes that induced earlier laticifers plugging,
which also impaired the latex fl ow and yield. In conclusion, a possible crossover between the cytosolic
MVA and the plastidic 1-deoxy-D-xylulose-5-phosphate/2-C-methyl-D-erythritol-4-phosphate (DXP/
MEP) pathways is suggested, which might especially take place in the laticifers of the high-yielding
clones, to fulfi ll the requirement in isopentenyl pyrophosphate for more active rubber biosynthesis.

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Genomics of Hevea Rubber - Springer

Genomics of Hevea Rubber - Springer | Hevea brasiliensis | Scoop.it

Abstract

Hevea brasiliensis is the most recent domesticated tree species from Amazonian rain forest producing latex of commercial utility. Major hurdles for genetic improvement of rubber tree were attributed to its perennial nature, long juvenile period, and a narrow genetic base. Further, the limited availability of Hevea genomic resources/information is another impediment to genomics-assisted crop improvement. Improvement of rubber tree in terms of latex production through breeding was the major focus of the scientific community dealing with the crop. Due to unidirectional selection for yield, other secondary attributes of rubber plants were lost during the process of developing high-yielding clones. Work on plant genomics gained momentum only after whole genome sequencing of Arabidopsis thaliana in 2000 (Arabidopsis Genome Initiative, 2000) followed by rice (International Rice Genome Sequencing Project, 2002) and poplar, the first tree genome (International Populus Genome Consortium, 2004). However, rubber genomics is still in its infancy. Initial molecular work started in the 1990s with cloning and characterization of latex biosynthesis genes followed by the studies on gene expression influenced by various biotic and abiotic stresses, tapping panel dryness (TPD), and ethylene stimulation of latex production. Simultaneously, different genetic markers were established in rubber for understanding the inheritance and diversity of natural variation existing among the Wickham and wild populations. Genetic markers were used successfully to generate linkage map for QTLs involving disease tolerance. During the last decade, transgenic research also progressed significantly with the development of transgenic Hevea clones with overexpressed MnSOD gene effective against TPD and drought stress. In recent years, with the advent of new-generation sequencing techniques, large-scale EST generation in rubber had been possible, which provided insights into genomic architecture and helped to elucidate genes involved in biological processes like latex production. In the absence of whole genome sequence information, the available transcriptome sequences form a potential resource to be utilized in genetic enhancement of rubber tree. The future challenge is to translate and integrate available genomic knowledge into appropriate methodologies, which we believe will revolutionize future Hevea breeding program.

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SpringerPlus | Abstract | Effect of rubber wood biochar on nutrition and growth of nursery plants of Hevea brasiliensis established in an Ultisol

Application of biochar alters availability of nutrients and acidic cations in soils which in turn could affect growth of plant to different degrees.
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Abstract (provisional)

Application of biochar alters availability of nutrients and acidic cations in soils which in turn could affect growth of plant to different degrees. Effect of rubber wood biochar amendment on the growth and nutritional status of Hevea nursery plants was determined in this study. Biochar were applied at 1% and 2% (w/w) with and without the recommended rates of N and Mg liquid fertilizers (LF). Two control treatments with 0% biochar but with and without recommended levels of all N, P, K, and Mg LF were also included. Application of biochar alone has a significant positive effect on above ground dry matter accumulation of the rootstock seedling (81% over the absolute control) while no effect on the scion growth. Growth of plants in LF added treatments were much higher. Combining 2% biochar with N and Mg significantly increased the above ground dry matter accumulation over N-P-K-Mg only treatment in both rootstock seedling (29%) and the scion (61%). Biochar only application did not affect the N and P and decreased K and Ca concentrations in leaves. When combined with N and Mg fertilizers however, biochar significantly increased total N, P, Mg and Ca uptake. Biochar only application (2%) significantly decreased the leaf Mn concentrations in the seedling probably due to decrease in Mn availability as a result of increase in soil pH. The increase in soil pH due to biochar addition decreased with time close to original values in soils that received LF, possibly due to sulfate of ammonia. We concluded that application of rubber wood biochar (upto 2% w/w) could improve the growth of Hevea plants with the use of only N and Mg fertilizers under nursery conditions tested in this experiment.

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Callogenesis and Somatic embryogenesis induction in Hevea brasiliensis: effects of fruit shelf-life and carbon source

An experiment was conducted to study the effect of the fruit shelf-life and the
concentrations of carbon source on somatic embryogenesis via callogenesis of Hevea
brasiliensis. Fruits harvested were stored at 15°C during 1, 5, 7, 12 and 15 days and the
inner integuments obtained from seed were used as explants. The experiments were
performed under carbon source treatments with three concentrations for glucose and five
concentrations for sucrose. Under these conditions, the percentage of explants forming
calli was better during the first week of fruit preservation regardless of the carbon source
but at high concentration. However, beyond 7 days of fruits shelf-life, sucrose is best to
induce callus unlike glucose but with high concentration. The best rate of embryogenic
calli was also obtained with sucrose. The percentages of callogenic explants and
embryogenic calli have decreased sharply with the shelf-life of fruit at 15°C. So, to
maintain an embryogenic potential of explants in situations of long-term conservation of
fruits, sucrose can be used at 234 mM of concentration or default at 111 mM sucrose.
These sucrose concentrations are conducive to induce embryogenic calli with explants
coming to rubber fruits after a long time of preservation.
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H51C-1355: Leaf ecophysiology of rubber (Hevea brasiliensis) and its implication to stand-level transpiration in the Asian monsoon in mainland Southeast Asia - AGU Fall Meeting 2012

H51C-1355: Leaf ecophysiology of rubber (Hevea brasiliensis) and its implication to stand-level transpiration in the Asian monsoon in mainland Southeast Asia - AGU Fall Meeting 2012 | Hevea brasiliensis | Scoop.it

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H51C-1355: Leaf ecophysiology of rubber (Hevea brasiliensis) and its implication to stand-level transpiration in the Asian monsoon in mainland Southeast Asia

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Authors: Yoshiyuki Miyazawa1, 3, Nakako Kobayashi2, Ryan G Mudd3, Song Yin4, Tiva LimKhan4, Thomas W Giambelluca3, Tomo'omi Kumagai2, 1

Author Institutions: 1. Research Institute for East Asia Environment, Kyushu University, Fukuoka, Japan; 2. Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya, Japan; 3. Department of Geography, University of Hawai'i at Manoa, Honolulu, HI, USA; 4. Rebber Research Institute of Cambodia, Phnom Penh, Cambodia

General InformationDiscussion

In Indochina Peninsula, rubber (Hevea brasiliensis) plantation is expanding rapidly as the major commercial crop. Rubber, which is a native of Amazon rainforests, are thought to have transpiration characteristics different from other native species in this region, which is characterized by high rainfall occurs in rainy season and severe drought in dry season. Studies suggested high stand transpiration rate (E) in rubber plantations, possibly due to the water use even in dry seasons or to high leaf photosynthetic capacity. Despite recent advances about the leaf-level measurements in leaf gas exchange traits, knowledge has been collected without clear linkage to the seasonal trends in stand-level gas exchange and its seasonal trends. In this study, we monitored the leaf-level photosynthetic capacity (Vcmax25) and a parameter for stomatal control (m, Ball et al. 1987) to show whether changes in atmospheric environments and leaf gas exchange traits explain the high E and its seasonal trends (annual peak in mid rainy season). Results showed that rubber had Vcmax25 and m similar to temperate broadleaved tree species and higher than other species in Indochina Peninsula, indicating that high Vcmax25 would be responsible for the higher E than other forests in Indochina Peninsula. Vcmax25 reached an annual maximum soon after leaf expansion before the beginning of rainy season, keep the level until soon before leaf fall in mid dry season and did not supported the hypothesis that these parameters increased in mid rainy season. The m also showed slight seasonal variations without clear trends. Multilayer model well modeled the diurnal trends in measured E using sap flow measurements, except soon after leaf expansion. Constant leaf gas exchange rates and good reproduction of finer time scale E suggested that increased E in mid rainy season was not due to the increased evaporative demand or changes in leaf gas exchange rates, but to the increased LAI. Poor modeling soon after leaf expansion suggested the effects of soil drought on E, and prolonged dry season is thought to strongly modify the E of rubber plantation in this region.

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UNDECAPRENYL PYROPHOSPHATE SYNTHASE FROM THE PLANT HEVEA BRASILIENSIS - UNIVERSITI SAINS MALAYSIA

FIELD OF INVENTION

The present invention relates to a transcriptome encoding plant enzyme homologous to undecaprenyl pyrophosphate synthase and a gene encoding this enzyme. More particularly, the present invention provides the undecaprenyl pyrophosphate synthase homologues and its application in the production of natural rubber in the plant of Hevea brasiliensis, as well as a transgenic H. brasiliensis plant thereof.

BACKGROUND OF THE INVENTION Natural rubber is a raw material of great importance in most of the industries. It is a high molecular mass polymer of isoprene units with cis configuration. It is naturally produced in over 200 species of plants. However, there are only two of these plants, H. brasiliensis and Parthenium argentatum, produce sufficiently high molecular weight rubber to be utilized for industrial purposes, of which H. brasiliensis is deemed the chief source of commercial rubber. It is known in the art that the world supply of natural rubber is barely keeping up with global demand for 12 million tons of natural rubber in year 2020. As there is an increasing global demand on rubber, further improvement of natural rubber production is necessary. Thus, there is a significant interest in studying rubber biosynthesis and exploring the molecular biology concept involved in this rubber biosynthesis.

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Influence of age and girth at opening on rubber yield, biochemical and tapping panel dryness parameters of Hevea brasiliensis in determining tapping norms

The incidence of several girths or tapping start period on the parameters of rubber yield, the physiological profile and the sensitivity to tapping panel dryness of Hevea brasiliensis have been studied for a decade in southeastern rubber growing area of Côte d'Ivoire. The study was conducted from so called early (tapping start at 40, 45 cm girth) and/or late (opening at 55, 60 and 65 cm girth) tapping applied to clones GT 1, PB 217 and PB 235. This study shows that starting tapping clone GT 1 at 40 cm girth and clones PB 217 and PB 235 at 50 cm are the best treatments in terms of rubber yield, physiological parameters and tapping panel dryness. These girths at the opening were reached at approximately 6 years after planting, regardless of the clone. The satisfactory results recorded demonstrate the preponderance of the notion of "opening age" over that of circumference of tapping start. Thus, the age of 6 years after planting seems to be the best period to start tapping rubber trees, because it is a good benchmark of physiological maturity in Hevea brasiliensis. Despite this precedence of the age over the girth, the different results indicate the need to use both criteria to take into account a delay in the growth and especially a difference in the vegetative growth of the clones planted.

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Screening of rubber (Hevea brasiliensis Muell. Arg.) rootstocks for the white root disease resistance

The white root disease caused by Rigidoporus microporus (Sw.) Overeem is a destructive disease in rubber plantation, particularly in southern Thailand. It persists on dead or live root debris for a long time. In this study, resistant clones of white root disease were screened. Pathagenicity tests of R.microporus in 10 local clones (PSU1, PSU2), Kantang, Bangmark, Sakraphangsurin, Bangrak, Khaowiset, Wangkere, Bangdee and Huaiyot districts) were done, compared with clone RRIM 600 and GT 1. The experiment was designed as a completely randomized design (CRD) with 5 replications. The following data were recorded for 2-week interval within 5 months: root distributions, area under disease progress curves (AUDPC), growth and symptom of rubber seedlings. Results indicated that the most of active root proliferation of 45-60 cm soil layer depth from the soil surface. Root growth of seedlings from clone Bangmark and Huaiyot districts showed significantly higher than RRIM 600, GT 1 and the other clones. With the AUDPC observation, the seedlings from clone Bangmark, Kantang and Prince of Songkla University (PSU1) were significanly higher P>0.05 )AUDPC) than the other clones. Growth of each clone was monitored by measuring height, circumference and number of petiole per seedling, the seedlings from clone Bangrak exhibited the highest growth. Symptom development of the seedlings from clone Kantang, Khaowiset districts and GT 1 clones were evident, around 50%. Among 10 local clones, RRIM 600 and GT 1 clones, the seedlings from Sakraphangsurin, Bangrak districts, PSU1 and PSU2 clones tended to exhibit white root disease resistance.

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Thailand aims to buy 250000 mt of natural rubber by March: reports - Platts

Thailand aims to buy 250000 mt of natural rubber by March: reports - Platts | Hevea brasiliensis | Scoop.it
Thailand aims to buy 250000 mt of natural rubber by March: reportsPlattsThailand plans to boost the natural rubber market by buying 250,000 mt of the commodity by March, news reports said Thursday, citing deputy farm minister Yuttapong Charasathien.
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Identification of genes differentially expressed in the roots of rubber tree (Hevea brasiliensis Muell. Arg.) in response to phosphorus deficiency - Online First - Springer

Identification of genes differentially expressed in the roots of rubber tree (Hevea brasiliensis Muell. Arg.) in response to phosphorus deficiency - Online First - Springer | Hevea brasiliensis | Scoop.it

Phosphorus (P) is an essential macronutrient for plant growth and development. P deficiency could affect rubber tree productivity seriously, and understanding the mechanism responses of the rubber tree under the P deficiency will be helpful to improving rubber tree productivity. The molecular mechanism by which the rubber trees respond to a P-deficiency is a complex network involving many processes. To identify the genes differentially expressed in that response, we constructed subtractive suppression hybridization libraries for roots of plants growing under deficient or sufficient conditions. We identified 94 up-regulated genes from the forward library and 45 down-regulated from the reverse library. These differentially expressed genes were categorized into eight groups representing functions in metabolism, transcription, signal transduction, protein synthesis, transport, stress responses, photosynthesis, and development. We also performed quantitative real-time PCR to investigate the expression profiles of eight randomly selected clones. Our results provide useful information for further study of the molecular mechanism for adaptations to a P-deficiency in this species. Further characterization and functional analysis of these differentially expressed genes will help us improve its phosphorus utilization and overall productivity

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Diversidade genética de acessos cultivados e espécies silvestres de seringueira por meio de marcadores EST‑SSR

ABSTRACT

The objective of this work was to evaluate the efficiency of EST‑SSR markers in the assessment of the genetic diversity of rubber tree genotypes (Hevea brasiliensis) and to verify the transferability of these markers for wild species of Hevea. Forty‑five rubber tree accessions from the Instituto Agronômico (Campinas, SP, Brazil) and six wild species were used. Information provided by modified Roger's genetic distance were used to analyze EST‑SSR data. UPGMA clustering divided the samples into two major groups with high genetic differentiation, while the software Structure distributed the 51 clones into eight groups. A parallel could be established between both clustering analyses. The 30 polymorphic EST‑SSRs showed from two to ten alleles and were efficient in amplifying the six wild species. Functional EST‑SSR microsatellites are efficient in evaluating the genetic diversity among rubber tree clones and can be used to translate the genetic differences among cultivars and to fingerprint closely related materials. The accessions from the Instituto Agronômico show high genetic diversity. The EST‑SSR markers, developed from Hevea brasiliensis, show transferability and are able to amplify other species of Hevea.

Index terms: fingerprinting analysis, genetic structure, functional molecular markers, polymorphism information content, transferability.

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Breeding Hevea brasiliensis for yield, growth and SALB resistance for high disease environments

Breeding Hevea brasiliensis for yield, growth and SALB resistance for high disease environments | Hevea brasiliensis | Scoop.it

The CIRAD-Michelin-Brazil (CMB) breeding program was set up in 1992 and has produced several genotypes as alternative varieties for growing in suboptimal regions and areas affected by South American Leaf Blight (SALB). From a large parent population of more than 113 clones, the program developed CMB genotypes evaluated in large-scale clone trials. Based on accurate knowledge of the parents’ agronomic potential, the CMB breeding program combined family and individual selection in the seedling evaluation trials. The segregation ratios of the SALB resistance traits in the progeny were used to identify and reject parents whose resistance was determined by a small number of genes, easily overcome by Microcyclus ulei strains. After evaluating the germplasm, 13 genotypes were selected for evaluation of their resistance, girth and rubber production in a trial network covering eight sites in Brazil and Ecuador. There were significant differences between clones, sites and clone-site interactions. The resistance of the clones to SALB was confirmed for all sites, both for conidial and sexual fungal stages. The growth rate in Ecuador was always higher than in Brazil with the exception of one clone. Data from previous years of production for a few clones was used to estimate the potential yield of these clones compared to clones usually planted in Latin America. Simultaneous selection for SALB resistance, yield and growth resulted in promising genotypes which need to be tested in areas with different environments.

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In silico characterization of a novel β-1,3-glucanase gene from Bacillus amyloliquefaciens—a bacterial endophyte of Hevea brasiliensis antagonistic to Phytophthora meadii - Online First - Springer

In silico characterization of a novel β-1,3-glucanase gene from Bacillus amyloliquefaciens—a bacterial endophyte of Hevea brasiliensis antagonistic to Phytophthora meadii - Online First - Springer | Hevea brasiliensis | Scoop.it

We report the molecular characterization of β-1,3-glucanase-producing Bacillus amyloliquefaciens—an endophyte of Hevea brasiliensis antagonistic to Phytophthora meadii. After cloning and sequencing, the β-1,3-glucanase gene was found to be 747 bp in length. A homology model of the β-1,3-glucanase protein was built from the amino acid sequence obtained upon translation of the gene. The target β-1,3-glucanase protein and the template protein, endo β-1,3-1,4-glucanase protein (PDB ID: 3o5s), were found to share 94 % sequence identity and to have similar secondary and tertiary structures. In the modeled structure, three residues in the active site region of the template—Asn52, Ile157 and Val158—were substituted with Asp, Leu and Ala, respectively. Computer-aided docking studies of the substrate disaccharide (β-1, 3-glucan) with the target as well as with the template proteins showed that the two protein-substrate complexes were stabilized by three hydrogen bonds and by many van der Waals interactions. Although the binding energies and the number of hydrogen bonds were the same in both complexes, the orientations of the substrate in the active sites of the two proteins were different. These variations might be due to the change in the three amino acids in the active site region of the two proteins. The difference in substrate orientation in the active site could also affect the catalytic potential of the β-1,3 glucanase enzyme.

 

 

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EVALUATING THE ENDOPHYTIC FUNGAL COMMUNITY IN PLANTED AND WILD RUBBER TREES (Hevea brasiliensis)

Abstract: The main objectives of this dissertation project were to characterize and compare the fungal endophytic communities associated with rubber trees (Hevea brasiliensis) distributed in wild habitats and under plantations. This study recovered an extensive number of isolates (more than 2,500) from a large sample size (190 individual trees) distributed in diverse regions (various locations in Peru, Cameroon, and Mexico). Molecular and classic taxonomic tools were used to identify, quantify, describe, and compare the diversity of the different assemblages. Innovative phylogenetic analyses for species delimitation were superimposed with ecological data to recognize operational taxonomic units (OTUs) or "putative species" within commonly found species complexes, helping in the detection of meaningful differences between tree populations. Sapwood and leaf fragments showed high infection frequency, but sapwood was inhabited by a significantly higher number of species. More than 700 OTUs were recovered, supporting the hypothesis that tropical fungal endophytes are highly diverse. Furthermore, this study shows that not only leaf tissue can harbor a high diversity of endophytes, but also that sapwood can contain an even more diverse assemblage. Wild and managed habitats presented high species richness of comparable complexity (phylogenetic diversity). Nevertheless, main differences were found in the assemblage's taxonomic composition and frequency of specific strains. Trees growing within their native range were dominated by strains belonging to Trichoderma and even though they were also present in managed trees, plantations trees were dominated by strains of Colletotrichum. Species of Trichoderma are known for their biocontrol properties, whereas species of Colletotrichum have been always associated with plant disease.
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