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1.
Braz J Biol ; 83: e251075, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34669807

RESUMO

Plant-derived products can assist in the healing process of dermal wounds. It has been demonstrated that Hancornia speciosa latex present angiogenic, osteogenic, anti-inflammatory, and antioxidant activities. Then, it could contribute to the wound healing process. However, natural products in contact with skin may cause dermatitis. The objective of this work was to evaluate the allergic and irritant potential of H. speciosa serum fraction latex using in vitro assays. The obtained results showed that the H. speciosa serum fraction latex has a slightly irritant potential and is not cytotoxic neither allergenic for human cells. Moreover, we identified a remarkable low amount of proteins in this material in comparison to Hevea brasiliensis latex. This result could explain the non-allergenic potential of H. speciosa serum fraction latex because proteins present in latex are the main responsible for allergy. This biomaterial could be used as a non-allergenic source for development of new medicines.


Assuntos
Apocynaceae , Hevea , Alérgenos , Materiais Biocompatíveis , Humanos , Látex , Cicatrização
2.
J Plant Physiol ; 265: 153506, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34492526

RESUMO

Plant male sterility (MS) is an important agronomic trait that provides an efficient tool for hybridization and heterosis utilization of crops. Based on phenotypic and cytological observations, our study performed a multi-comparison transcriptome analysis strategy on multiple sterile and fertile rubber tree varieties using RNA-seq. Compared with the male-fertile varieties, a total of 1590 differentially expressed genes (DEGs) were detected in male-sterile varieties, including 970 up-regulated and 620 down-regulated transcripts in sterile varieties. Key DEGs were further assessed focusing on anther development, microsporogenesis and plant hormone metabolism. Twenty DEGs were selected randomly to validate transcriptome data using quantitative real-time PCR (qRT-PCR). Eleven key genes were subjected to expression pattern analysis using qRT-PCR and fluorescence in situ hybridization. Among them, nine genes, i.e., A6, GAI1, ACA7, TKPR1, CYP704B1, XTH26, MS1, MS35 and MYB33, that regulate callose metabolism, pollen wall formation, tapetum and microspores development were identified as candidate male-sterile genes. These findings provide insights into the molecular mechanism of male sterility in rubber tree.


Assuntos
Fertilidade/genética , Flores/crescimento & desenvolvimento , Flores/genética , Perfilação da Expressão Gênica , Hevea/genética , Infertilidade das Plantas/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo
3.
BMC Plant Biol ; 21(1): 420, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34517831

RESUMO

BACKGROUND: Natural rubber (cis-1,4-polyioprene, NR) is an indispensable industrial raw material obtained from the Pará rubber tree (H. brasiliensis). Natural rubber cannot be replaced by synthetic rubber compounds because of the superior resilience, elasticity, abrasion resistance, efficient heat dispersion, and impact resistance of NR. In NR production, latex is harvested by periodical tapping of the trunk bark. Ethylene enhances and prolongs latex flow and latex regeneration. Ethephon, which is an ethylene-releasing compound, applied to the trunk before tapping usually results in a 1.5- to 2-fold increase in latex yield. However, intense mechanical damage to bark tissues by excessive tapping and/or over-stimulation with ethephon induces severe oxidative stress in laticifer cells, which often causes tapping panel dryness (TPD) syndrome. To enhance NR production without causing TPD, an improved understanding of the molecular mechanism of the ethylene response in the Pará rubber tree is required. Therefore, we investigated gene expression in response to ethephon treatment using Pará rubber tree seedlings as a model system. RESULTS: After ethephon treatment, 3270 genes showed significant differences in expression compared with the mock treatment. Genes associated with carotenoids, flavonoids, and abscisic acid biosynthesis were significantly upregulated by ethephon treatment, which might contribute to an increase in latex flow. Genes associated with secondary cell wall formation were downregulated, which might be because of the reduced sugar supply. Given that sucrose is an important molecule for NR production, a trade-off may arise between NR production and cell wall formation for plant growth and for wound healing at the tapping panel. CONCLUSIONS: Dynamic changes in gene expression occur specifically in response to ethephon treatment. Certain genes identified may potentially contribute to latex production or TPD suppression. These data provide valuable information to understand the mechanism of ethylene stimulation, and will contribute to improved management practices and/or molecular breeding to attain higher yields of latex from Pará rubber trees.


Assuntos
Etilenos/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Hevea/genética , Hevea/metabolismo , Látex/metabolismo , Plântula/genética , Plântula/metabolismo , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Genes de Plantas , Indonésia
4.
Plant Physiol Biochem ; 167: 376-384, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34404008

RESUMO

Ficus altissima Blume, a horticultural plant in tropical and warm subtropical regions, can produce natural rubber with comparable molecular weight to the Hevea brasiliensis rubber. The F. altissima latex has an acidic pH (about 4.89). The rubber particle size distribution is a unimodal profile, and the peak frequency is at a size of 4.5 µm. The natural rubber of F. altissima was determined to be a cis conformation via 13C NMR. The Mp (molecular weight of the peak maxima) of the deproteinized F. altissima rubber was 9.34 × 105 Da. LC-MS was used to identify the proteins of rubber particles and serum. The most abundant protein of the creamy rubber particle layer is an acid phosphatase, while the most abundant proteins of serum were an (R)-mandelonitrilelyase and a polygalacturonase inhibitor. Pharmaceutical proteins (ficins) or enzymes related to the biosynthesis of natural medicines (a cannabidiolic acid synthase and two lupeol synthase) were identified in F. altissima latex. The data of this study may be helpful for research on the functions of latex in latex-borne plants and the biosynthesis mechanism of natural rubber.


Assuntos
Ficus , Hevea , Látex , Proteínas de Plantas , Borracha
5.
An Acad Bras Cienc ; 93(3): e20191336, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34287455

RESUMO

The development of crops is related to their nutritional status and the leaf chlorophyll apparent index. The objective of this study was to use fuzzy classification to determine the degree of membership (fuzzy index - FI) of macronutrientes and leaf micronutrients classified as low, adequate and high, quantify the chlorophyll index and to determine the spatial variability of these attributes for the rubber tree (Hevea brasiliensis) (Fx 3864) at the initial stage of development, aiming at the definition of management zones. Sampling grid regulates at 6x7 m spacing was built to determine the attributes: chlorophyll a and b, macro and leaf micronutrients, totaling 100 sample points. The fuzzy classification and geostatistical was used to map the nutritional status of the rubber tree. In the fuzzy analysis the macronutrient map shows the degree of membership 0.50

Assuntos
Hevea , Clorofila , Clorofila A , Estado Nutricional , Folhas de Planta
6.
PLoS One ; 16(7): e0254541, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34320014

RESUMO

Corynespora cassiicola, a fungal plant pathogen with a large host range, causes important damages in rubber tree (Hevea brasiliensis), in Asia and Africa. A small secreted protein named cassiicolin was previously identified as a necrotrophic effector required for the virulence of C. cassiicola in specific rubber tree clones. The objective of this study was to decipher the cassiicolin-mediated molecular mechanisms involved in this compatible interaction. We comparatively analyzed the RNA-Seq transcriptomic profiles of leaves treated or not with the purified cassiicolin Cas1, in two rubber clones: PB260 (susceptible) and RRIM600 (tolerant). The reads were mapped against a synthetic transcriptome composed of all available transcriptomic references from the two clones. Genes differentially expressed in response to cassiicolin Cas1 were identified, in each clone, at two different time-points. After de novo annotation of the synthetic transcriptome, we analyzed GO enrichment of the differentially expressed genes in order to elucidate the main functional pathways impacted by cassiicolin. Cassiicolin induced qualitatively similar transcriptional modifications in both the susceptible and the tolerant clones, with a strong negative impact on photosynthesis, and the activation of defense responses via redox signaling, production of pathogenesis-related protein, or activation of the secondary metabolism. In the tolerant clone, transcriptional reprogramming occurred earlier but remained moderate. By contrast, the susceptible clone displayed a late but huge transcriptional burst, characterized by massive induction of phosphorylation events and all the features of a hypersensitive response. These results confirm that cassiicolin Cas1 is a necrotrophic effector triggering a hypersensitive response in susceptible rubber clones, in agreement with the necrotrophic-effector-triggered susceptibility model.


Assuntos
Ascomicetos/metabolismo , Proteínas Fúngicas/farmacologia , Hevea/genética , Micotoxinas/farmacologia , Transcriptoma/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Hevea/metabolismo , Hevea/microbiologia , Micotoxinas/genética , Micotoxinas/metabolismo , Fosforilação , Fotossíntese/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Análise de Componente Principal , RNA de Plantas/química , RNA de Plantas/genética , RNA de Plantas/metabolismo , Transdução de Sinais/genética , Regulação para Cima/efeitos dos fármacos
7.
Mater Sci Eng C Mater Biol Appl ; 126: 112126, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082943

RESUMO

The past decades have witnessed tremendous progress in biomaterials in terms of functionalities and applications. To realize various functions such as tissue engineering, tissue repair, and controlled release of therapeutics, a biocompatible and biologically active material is often needed. However, it is a difficult task to find either synthetic or natural materials suitable for in vivo applications. Nature has provided us with the natural rubber latex from the rubber tree Hevea brasiliensis, a natural polymer that is biocompatible and has been proved as inducing tissue repair by enhancing the vasculogenesis process, guiding and recruiting cells responsible for osteogenesis, and acting as a solid matrix for controlled drug release. It would be extremely useful if medical devices can be fabricated with materials that have these biological properties. Recently, various types of natural rubber latex-based biomedical devices have been developed to enhance tissue repair by taking advantage of its biological properties. Most of them were used to enhance tissue repair in chronic wounds and critical bone defects. Others were used to design drug release systems to locally release therapeutics in a sustained and controlled manner. Here, we summarize recent progress made in these areas. Specifically, we compare various applications and their performance metrics. We also discuss critical problems with the use of natural rubber latex in biomedical applications and highlight future opportunities for biomedical devices produced either with pre-treated natural rubber latex or with proteins purified from the natural rubber latex.


Assuntos
Hevea , Liberação Controlada de Fármacos , Hevea/metabolismo , Látex , Proteínas de Plantas/metabolismo , Proteínas , Borracha
8.
BMC Plant Biol ; 21(1): 244, 2021 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-34051757

RESUMO

BACKGROUND: The processabilities and mechanical properties of natural rubber depend greatly on its molecular weight (MW) and molecular weight distribution (MWD). However, the mechanisms underlying the regulation of molecular weight during rubber biosynthesis remain unclear. RESULTS: In the present study, we determined the MW and particle size of latex from 1-year-old virgin trees and 30-year-old regularly tapped trees of the Hevea clones Reyan7-33-97 and RRIM600. The results showed that both the MW and the particle size of latex varied between these two clones and increased with tree age. Latex from RRIM600 trees had a smaller average particle size than that from Reyan7-33-97 trees of the same age. In 1-year-old trees, the Reyan7-33-97 latex displayed a slightly higher MW than that of RRIM600, whereas in 30-year-old trees, the RRIM600 latex had a significantly higher MW than the Reyan7-33-97 latex. Comparative analysis of the transcriptome profiles indicated that the average rubber particle size is negatively correlated with the expression levels of rubber particle associated proteins, and that the high-MW traits of latex are closely correlated with the enhanced expression of isopentenyl pyrophosphate (IPP) monomer-generating pathway genes and downstream allylic diphosphate (APP) initiator-consuming non-rubber pathways. By bioinformatics analysis, we further identified a group of transcription factors that potentially regulate the biosynthesis of IPP. CONCLUSIONS: Altogether, our results revealed the potential regulatory mechanisms involving gene expression variations in IPP-generating pathways and the non-rubber isoprenoid pathways, which affect the ratios and contents of IPP and APP initiators, resulting in significant rubber MW variations among same-aged trees of the Hevea clones Reyan7-33-97 and RRIM600. Our findings provide a better understanding of rubber biosynthesis and lay the foundation for genetic improvement of rubber quality in H. brasiliensis.


Assuntos
Hevea/genética , Látex/metabolismo , Transcriptoma , Hevea/metabolismo , Peso Molecular
9.
Plant Physiol Biochem ; 162: 211-220, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33706182

RESUMO

Fructokinase (FRK) mediates fructose phosphorylation to regulate the carbon flow and its assignment to sink tissues. Out of five HbFRKs in the genome of the rubber tree, three (HbFRK1-3) that were highly expressed in latex (cytoplasm of laticifers) were isolated and examined. According to phylogenetic analysis and intracellular location experiment, both HbFRK2 and HbFRK3 were highly possible to be expressed in cytosol, while HbFRK1 was in plastid. As the predominant isoform in laticifers, HbFRK2 had the highest transcripts, followed by HbFRK3 and HbFRK1. In enzymatic function, HbFRK2 also showed the highest affinity for fructose. To examine the roles of FRKs in latex yield and regeneration, changes in HbFRKs were examined when latex outflow from the trees were increased through two experimental interventions. In the first approach, tapping was initiated on previously untapped trees, resulting in latex yield increasing with consecutive tapping at the initial stage before it stabilized. In the second approach, latex yield from trees that were already in regular tapping was stimulated by treatment with the ethylene-based yield stimulant, ethephon. Using either method to induce an increase in latex yield, the abundance of HbFRK2 and HbFRK3 in transcripts, was increased. This development, which was especially marked in HbFRK2, may reflect a strengthening of glycolysis to meet the carbon flux and energy demands for increased rubber biosynthesis to replace rubber lost in the increased latex yield. Our results, therefore, suggest that HbFRK2 plays a critical role in fructose catabolism to facilitate rubber regeneration in the commercially exploited rubber tree.


Assuntos
Hevea , Frutoquinases/genética , Regulação da Expressão Gênica de Plantas , Hevea/genética , Hevea/metabolismo , Látex/metabolismo , Filogenia , Isoformas de Proteínas , Borracha
10.
BMC Genomics ; 22(1): 183, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33711923

RESUMO

BACKGROUND: Somatic embryogenesis (SE) is a promising technology for plant vegetative propagation, which has an important role in tree breeding. Though rubber tree (Hevea brasiliensis Muell. Arg.) SE has been founded, few late SE-related genes have been identified and the molecular regulation mechanisms of late SE are still not well understood. RESULTS: In this study, the transcriptomes of embryogenic callus (EC), primary embryo (PE), cotyledonary embryo (CE), abnormal embryo (AE), mature cotyledonary embryo (MCE) and withered abnormal embryo (WAE) were analyzed. A total of 887,852,416 clean reads were generated, 85.92% of them were mapped to the rubber tree genome. The de novo assembly generated 36,937 unigenes. The differentially expressed genes (DEGs) were identified in the pairwise comparisons of CE vs. AE and MCE vs. WAE, respectively. The specific common DEGs were mainly involved in the phytohormones signaling pathway, biosynthesis of phenylpropanoid and starch and sucrose metabolism. Among them, hormone signal transduction related genes were significantly enriched, especially the auxin signaling factors (AUX-like1, GH3.1, SAUR32-like, IAA9-like, IAA14-like, IAA27-like, IAA28-like and ARF5-like). The transcription factors including WRKY40, WRKY70, MYBS3-like, MYB1R1-like, AIL6 and bHLH93-like were characterized as molecular markers for rubber tree late SE. CML13, CML36, CAM-7, SERK1 and LEAD-29-like were also related to rubber tree late SE. In addition, histone modification had crucial roles during rubber tree late SE. CONCLUSIONS: This study provides important information to elucidate the molecular regulation during rubber tree late SE.


Assuntos
Hevea , Desenvolvimento Embrionário , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Hevea/genética , Hevea/metabolismo , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transcriptoma
11.
J Agric Food Chem ; 69(13): 3797-3821, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33761246

RESUMO

As the second natural rubber resource, Eucommia ulmoides rubber (EUR) from Eucommia ulmoides Oliver is mainly composed of trans-1,4-polyisoprene, which is the isomer of natural rubber cis-1,4-polyisoprene from Hevea brasiliensis. In the past few years, the great potential application of EUR has received increasing attention, and there is a growing awareness that the natural polymer EUR could become an emerging research topic in field of the novel materials due to its unique and excellent duality of both rubber and plastic. To gain insight into its further development, in this review, the extraction, structure, physicochemical properties, and modification of EUR are discussed in detail. More emphasis on the potential applications in the fields of the environment, agriculture, engineering, and biomedical engineering is summarized. Finally, some insights into the challenges and perspectives of EUR are also suggested.


Assuntos
Eucommiaceae , Hevea , Hemiterpenos , Polímeros , Borracha
12.
J Environ Manage ; 285: 112147, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33607560

RESUMO

Land degradation is a global problem caused by improper agricultural practices. In tropical China, the rubber (Hevea brasiliensis) plantations are predominantly practiced on forest-cleared lands, considering their sustainable land management potential compared to annual cropping. However, all rubber plantations may not have similar land management capacity. Soil quality index (SQI) can reveal the overall soil status with a single score, which is an efficient tool to evaluate the soil quality of each category of rubber plantations. We investigated 23 soil physical and chemical parameters of three categories of rubber plantations and a primary rainforest, and derived SQI based on these parameters. Soil samples were collected from a rubber monoculture (RM), a rubber-Camellia sinensis agroforestry (RT), a rubber-Dracaena cochinchinensis agroforestry (RD), and a primary rainforest (RF). The results showed that the SQI value of the RM decreased by 15.50% compared to the RF, with a significant degree of soil nutrient loss (18.90%). This indicates that monocultural rubber cultivation is causing land degradation to some extent. However, the SQI was significantly enhanced by rubber-based agroforestry practices (25.30% by RT and 33.10% by RD) compared to the RM, suggesting that polyculture practices are suitable to recover the soil quality in degraded agricultural lands. Moreover, the chemical parameters contributed more to the SQI than did the physical parameters, indicating that nutrient management is important in soil quality recovery. Overall, our results suggest that agroforestry should be preferred over monoculture in the rubber plantations for sustainable land management in tropical China.


Assuntos
Hevea , Solo , Agricultura , China , Floresta Úmida
13.
Biosci Biotechnol Biochem ; 85(3): 562-567, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33590039

RESUMO

Virus-induced gene silencing (VIGS) is a powerful gene-silencing tool that has been intensively applied in plants. To data, the application of VIGS in rubber tree has not yet been reported. In this study, we described the efficient gene silencing in rubber tree by VIGS. The gene encoding Hevea brasiliensis phytoene desaturase (HbPDS) was identified in rubber tree genome. Small interfering RNAs from HbPDS and the silencing gene fragment were predicted and a length of 399 bp was selected to be tested. We showed that the tobacco rattle virus (TRV)-VIGS could induce effective HbPDS silencing in rubber tree. This study was the first to report VIGS in rubber tree. The present TRV-VIGS method could be used to perform reverse genetic approaches to identify unknown gene functions and might be further applied to produce gene silenced rubber tree plants, to advance functional gene of rubber tree.


Assuntos
Inativação Gênica/fisiologia , Genes de Plantas , Hevea/genética , Vírus de Plantas/fisiologia , RNA Interferente Pequeno/genética
14.
Tree Physiol ; 41(7): 1278-1288, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-33554256

RESUMO

Natural rubber is an important industrial raw material and is commercially produced by rubber trees (Hevea brasiliensis). The sucrose transporter HbSUT3 plays an essential role in rubber production. Its expression in latex (cytoplasm of rubber-producing laticifers) is induced by bark treatment with Ethrel, an ethylene releaser, and the inducing effect correlates well with Ethrel-stimulated rubber yield increase. However, the mechanisms of ethylene induction on HbSUT3 expression are not known. Here, five Ethylene Response Factor (ERF) genes were identified from the cDNA library of Hevea latex by yeast one-hybrid screening with the promoter of HbSUT3 gene as bait. As revealed in a tobacco (Nicotiana tabacum) protoplast transient expression system, these HbERFs were mainly localized in the nucleus and four of them exhibited apparent transactivation activity. Of the five HbERF genes, HbERF-IXc4 was the most frequently screened in yeast one-hybrid, accounting for 65% of the ERF clones obtained. Moreover, among the five HbERFs, HbERF-IXc4 showed the strongest transactivation capacity when expressed in tobacco protoplast, the highest transcript abundance in latex and a close expressional correlation with its target gene, HbSUT3, in response to the Ethrel treatment. Taken together, our results indicate that ERFs, especially HbERF-IXc4, are critically involved in the activation of HbSUT3 expression in latex after Ethrel treatment on Hevea bark, and thus the stimulated latex yield.


Assuntos
Hevea , Etilenos , Regulação da Expressão Gênica de Plantas , Hevea/genética , Hevea/metabolismo , Látex , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sacarose
15.
Sci Rep ; 11(1): 1081, 2021 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33441718

RESUMO

The objective of this study was to evaluate the genetic variability of natural rubber latex traits among 44 elite genotypes of the rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Müell. Arg.]. Multivariate analysis and machine learning techniques were used, targeting the selection of parents that demonstrate superior characters. We analyzed traits related to technological or physicochemical properties of natural rubber latex, such as Wallace plasticity (P0), the plasticity retention index [PRI (%)], Mooney viscosity (VR), ash percentage (Ash), acetone extract percentage (AE), and nitrogen percentage (N), to study genetic diversity. Multivariate [unweighted pair group method with arithmetic means (UPGMA) and Tocher)] and machine learning techniques [K-means and Kohonen's self-organizing maps (SOMs)] were employed. The genotypes showed high genetic variability for some of the evaluated traits. The traits PRI, Ash, and PO contributed the most to genetic diversity. The genotypes were classified into six clusters by the UPGMA method, and the results were consistent with the Tocher, K-means and SOM results. PRI can be used to improve the industrial potential of clones. The clones IAC 418 and PB 326 were the most divergent, followed by IAC 404 and IAC 56. These genotypes and others from the IAC 500 and 400 series could be used to start a breeding program. These combinations offer greater heterotic potential than the others, which can be used to improve components of rubber latex quality. Thus, it is important to consider the quality of rubber latex in the early stage of breeding programs.


Assuntos
Hevea/genética , Variação Genética , Genoma de Planta , Melhoramento Vegetal , Proteínas de Plantas/genética
16.
Physiol Plant ; 171(1): 151-160, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33034379

RESUMO

WRKY group transcription factors of model plants and major crops are confirmed to play essential roles in stress responses, senescence, secondary metabolism processes and hormone signal transduction. Previous studies have identified 81 HbWRKY genes from Hevea brasiliensis (the Pará rubber tree), but the functions of HbWRKYs in response to abiotic stresses and leaf senescence are unclear. In this study, one novel group IIc WRKY transcription factor named HbWRKY82 was identified and characterized as a stress-associated WRKY in rubber tree. Transient expression and transcriptional activation analyses indicated that HbWRKY82 encoded a nuclear protein and functioned as a transcription activator. The transcription levels of HbWRKY82 were induced by exogenous Ethrel (ET) (ethylene releaser) and abscisic acid (ABA) stimulations, down-regulated in tapping panel dryness rubber trees, and also exhibits significant decrease during the progression of leaf senescence. Overexpression of HbWRKY82 in Arabidopsis improved the tolerance to dehydration and salinity, and decreased the sensitivity to exogenous ABA. Moreover, real-time quantitative PCR analysis demonstrated that HbWRKY82 regulated the transcriptional expression of several stress-responsive genes (DREB1A, ERD10, HKT1, P5CS, RD22, RD29B, SKOR), leaf senescence marker genes (EIN3, WRKY53, NAP), ROS-related genes (RbohD, CSD1, CSD2, FSD3) and hormone signaling genes (EIN3, ABF3, ABF4). Collectively, our findings suggested that HbWRKY82 might function as an important transcriptional regulator in ET- and ABA-mediated leaf senescence and abiotic stress responses, and also be involved in tapping panel dryness, latex flow and regeneration processes of rubber trees via participating in the ET and reactive oxygen species signaling pathways.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Hevea , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica , Regulação da Expressão Gênica de Plantas , Hevea/genética , Hevea/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Estresse Fisiológico , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
17.
Tree Physiol ; 41(3): 460-471, 2021 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-33032325

RESUMO

Natural rubber, a strategically essential raw material used in manufacturing throughout the world, is produced from coagulated and refined latex of rubber tree (Hevea brasiliensis). It is known that phytohormone jasmonate (JA) plays an essential role in regulating latex biosynthesis. However, it is unclear how the JA signal is sensed in a rubber tree. Here, we showed that H. brasiliensis CORONATINE-INSENSITIVE 1 (HbCOI1) acts as a receptor that perceives JA to recruit H. brasiliensis JASMONATE ZIM DOMAIN1 (HbJAZ1) for signal transduction. We found that HbCOI1 restores male sterility and JA responses of the coi1-1 mutant in Arabidopsis. The identification of a JA receptor in the rubber tree is essential for elucidating the molecular mechanisms underlying JA-regulated latex biosynthesis. Our results elucidate the mechanism of JA perception in H. brasiliensis and also provide an efficient strategy to identify JA receptors in woody plants.


Assuntos
Hevea , Aminoácidos , Ciclopentanos/farmacologia , Regulação da Expressão Gênica de Plantas , Hevea/genética , Hevea/metabolismo , Indenos , Látex , Masculino , Oxilipinas , Transdução de Sinais
18.
J Plant Res ; 134(1): 43-53, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33108557

RESUMO

Natural rubber or latex from the Hevea brasiliensis is an important commodity in various economic sectors in today's modern society. Proteins have been detected in latex since the early twentieth century, and they are known to regulate various biological pathways within the H. brasiliensis trees such as the natural rubber biosynthesis, defence against pathogens, wound healing, and stress tolerance. However, the exact mechanisms of the pathways are still not clear. Proteomic analyses on latex have found various proteins and revealed how they fit into the mechanisms of the biological pathways. In the past three decades, there has been rapid latex protein identification due to the improvement of latex protein extraction methods, as well as the emergence of two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS). In this manuscript, we reviewed the methods of latex protein extraction that keeps on improving over the past three decades as well as the results of numerous latex protein identification and quantitation.


Assuntos
Hevea , Látex , Espectrometria de Massas , Proteínas de Plantas , Proteômica
19.
J Cosmet Dermatol ; 20(7): 2160-2167, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33185310

RESUMO

OBJECTIVES: Para rubber (Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg.)) is the important crop of the word. It has been vastly used in biomedical products. However, its pharmacologically application besides the latex is sparely to be explored especially the seed. Cellular biological activities of the standardized para rubber seed oil for hair loss treatment were therefore assessed. METHODS: Para rubber seed oil was prepared and standardized using GC/MS on the basis of its pharmacologically active fatty acids. The oil was safety assessed in human dermal papilla and DU-145 human prostate carcinoma. Cellular antioxidant activity was determined as well as proliferation stimulating efficacy and inhibitory effect against 5α-reductase. RESULTS: Oleic acid, fatty acid of cutaneous benefits, was majorly detected in the oil and followed by linoleic, palmitic, and stearic acids. The standardized para rubber seed oil was proved to be safe on human follicle dermal papilla and DU-145 human prostate carcinoma at the concentration of 0.1-50 and 0.1-100 µg/mL, respectively. The standardized para rubber seed oil stimulated the cell proliferation and posed cellular antioxidant activity in human dermal papilla at a comparable potency to minoxidil, dutasteride and vitamin C at the same tested concentration. In addition, the standardized para rubber seed oil inhibited 5α-reductase as examined in DU-145 human prostate carcinoma, although at a lesser degree than the standards at the same tested concentration. CONCLUSIONS: The standardized para rubber seed oil is evidenced as the safe and efficient bio-oil to be used for hair growth stimulating or reduce/suppress hair loss treatment.


Assuntos
Gorduras Insaturadas , Hevea , Alopecia , Humanos , Óleos Vegetais/farmacologia , Óleos Vegetais/uso terapêutico , Sementes
20.
Molecules ; 25(21)2020 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-33153210

RESUMO

Natural rubber is usually synthesized in the rubber particles present in the latex of rubber-producing plants such as the Pará rubber tree (Hevea brasiliensis) and rubber dandelion (Taraxacum kok-saghyz). Since the detailed lipid compositions of fresh latex and rubber particles of the plants are poorly known, the present study reports detailed compound lipid composition, focusing on phospholipids and galactolipids in the latex and rubber particles of the plants. In the fresh latex and rubber particles of both plants, phospholipids were much more dominant (85-99%) compared to galactolipids. Among the nine classes of phospholipids, phosphatidylcholines (PCs) were most abundant, at ~80%, in both plants. Among PCs, PC (36:4) and PC (34:2) were most abundant in the rubber tree and rubber dandelion, respectively. Two classes of galactolipids, monogalactosyl diacylglycerol and digalactosyl diacylglycerol, were detected as 12% and 1%, respectively, of total compound lipids in rubber tree, whereas their percentages in the rubber dandelion were negligible (< 1%). Overall, the compound lipid composition differed only slightly between the fresh latex and the rubber particles of both rubber plants. These results provide fundamental data on the lipid composition of rubber particles in two rubber-producing plants, which can serve as a basis for artificial rubber particle production in the future.


Assuntos
Hevea/química , Látex/química , Lipídeos/química , Taraxacum/química
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