Modification of C20 oxidase in tanshinone biosynthesis pathway / 中国中药杂志

Tanshinones are one of the main effective components of Salvia miltiorrhiza, which play important roles in the treatment of cardiovascular diseases. Microbial heterogony production of tanshinones can provide a large number of raw materials for the production of traditional Chinese medicine(TCM) preparations containing S. miltiorrhiza, reduce the extraction cost, and relieve the pressure of clinical medication. The biosynthetic pathway of tanshinones contains multiple P450 enzymes, and the catalytic element with high efficiency is the basis of microbial production of tanshinones. In this study, the protein modification of CYP76AK1, a key P450-C20 hydroxylase in tanshinone pathway, was researched. The protein modeling methods SWISS-MODEL, Robetta, and AlphaFold2 were used, and the protein model was analyzed to obtain the reliable protein structure. The semi-rational design of mutant protein was carried out by molecular docking and homologous alignment. The key amino acid sites affecting the oxidation activity of CYP76AK1 were identified by molecular docking. The function of the obtained mutations was studied with yeast expression system, and the CYP76AK1 mutations with continuous oxidation function to 11-hydroxysugiol were obtained. Four key amino acid sites that affected the oxidation acti-vity were analyzed, and the reliability of three protein modeling methods was analyzed according to the mutation results. The effective protein modification sites of CYP76AK1 were reported for the first time in this study, which provides a catalytic element for different oxidation activities at C20 site for the study of the synthetic biology of tanshinones and lays a foundation for the analysis of the conti-nuous oxidation mechanism of P450-C20 modification.

Effects of density on growth and gene transcription characteristics of Rehmannia glutinosa / 中国中药杂志

The present study analyzed the effects of planting density on the development, quality, and gene transcription characte-ristics of Rehmannia glutinosa using 85-5 and J9 as materials with three planting densities of 5 000, 25 000, and 50 000 plants/Mu(1 Mu≈667 m~2). The agronomic characteristics of leaves and tuberous roots, the content of catalpol and acteoside, and the changes of gene expression were determined. The results showed that the leaf size, the diameter of tuberous root, leaf biomass, tuberous root number, and tuberous root biomass per plant at low density were significantly higher than those of medium and high densities. The content of catalpol and acteoside in leaves was higher at high density. The content of catalpol in tuberous roots was higher at low density, and the change trend was similar to that in leaves, while the content of acteoside in tuberous roots was higher at high density. Transcriptome analysis found that about 1/2 of the expansin genes could change regularly in response to density treatment, which was rela-ted to the development of tuberous roots. The change trend of the gene expression of multiple catalytic enzymes involved in the biosynthesis of catalpol and acteoside was consistent with that of their content, which was presumedly involved in the accumulation and regulation of density-responsive medicinal components. Based on the analysis of the development, medicinal components, and gene expression characteristics of R. glutinosa at different densities, this study is expected to provide an important basis for regulating the quality and yield of medicinal materials of R. glutinosa by managing the planting density.

Pueraria lobate advances in molecular pharmacognosy / 中国中药杂志

Molecular pharmacognosy is a science of classification and identification, cultivation and protection, and production of active ingredients of graduated drugs at the molecular level. The proposal of molecular pharmacognosy allows the research of crude drugs to advance from the microscopic level to the genetic level. Pueraria lobata root, as a medicinal and edible plant, has high application value and economic value. There are many varieties that are easy to cause confusion, and it is not easy to distinguish and identify according to traditional identification methods. Moreover, the research of P. lobate root at the genetic level is still relatively shallow. the study received extensive attention of scholars. This article reviews recent research on molecular identification of P. lobate, transcriptome sequencing, cloning and synthesis of functional genes of P. lobate root in recent years in order to provide references for further promoting the development and utilization of P. lobate root and its active ingredients.

Molecular diagnosis and intraspecific genetic variability of root pathogens of arid legumes in Western Rajasthan, India / Diagnóstico molecular y la variabilidad genética intraespecífica de patógenos de raíces en leguminosas resistentes a sequías del oeste de Rajasthan, India

Abstract:The productivity of arid legumes, such as Clusterbean (Cyamopsis tetragonoloba), Cowpea (Vigna unguiculata), Moth bean (Vigna aconitifolia) and Horse gram (Macrotyloma uniflorum), may remain stagnant over decades because of their high susceptibility to root diseases. Besides, there is a limitation on the information about molecular diagnosis and intraspecific genetic variability of root pathogens in arid legumes. To contribute in this field, we assessed a total of 52 isolates from 88 root samples that were found infected with fungal pathogens in Jodhpur, Jaipur and Bikaner Districts of Rajasthan. Diseased roots samples were analyzed following standard microbiological methods for fungus extraction and purification, and for genetic studies. Irrespective of the geographical location from where the diseased samples were collected, all pathogen isolates were clustered in RAPD dendrograms as per their respective genera. Phylogram, based on multiple sequence alignment, revealed that different genera (i.e. Fusarium, Neocosmospora and Syncephalastrum), separated from each other, and species within the same genera, clustered together with their reference sequences with apreciable bootstrap values. Out of 20 representative isolates representing each cluster and all outgroups sequenced, eight were molecularly identified as Neocosmospora vasinfecta, five as Fusarium solani, two as Neocosmospora striata, two as Fusarium acutatum, one as Syncephalastrum monosporum, one as Fusarium oxysporum and one as Fusarium species. The root pathogens of the arid legumes were found neither restricted to a geographical location nor were host specific in nature. Fusarium solani wilt in cowpea and seedling rot in moth bean, F. oxysporum wilt in moth bean, F. acutatum damping off in cowpea and Clusterbean, Fusarium sp. seedling rot in Clusterbean, Neocosmospora striata root rot in cowpea and wilt in Clusterbean and Syncephalastrum monosporum root rot in Clusterbean were molecularly identified as new fungal records as pathogens causing root diseases in arid legumes. Rev. Biol. Trop. 64 (4): 1505-1518. Epub 2016 December 01.

Resumen:La producción de leguminosas resistentes a sequías como Cyamopsis tetragonoloba, Vigna unguiculata, Vigna aconitifolia y Macrotyloma uniflorum, puede permanecer inactiva durante décadas debido a su alta susceptibilidad a enfermedades en las raíces. Además, hay información limitada relacionada con el diagnóstico molecular y la variabilidad genética intraespecífica de patógenos de raíces en estas leguminosas resistentes a sequías. Para contribuir en esta área, evaluamos un total de 52 extractos de 88 raíces infectadas con patógenos fúngicos en los distritos de Jodhpur, Jaipur y Bikaner de Rajastán. Las muestras de raíces infectadas se analizaron siguiendo los métodos estándar de microbiología para extracción y purificación de hongos y para estudios genéticos. Independientemente del sitio donde se recolectaron las muestras contaminadas, todos los extractos patógenicos se agruparon en dendrogramas RAPD en cada uno de sus respectivos géneros. El filograma, basado en alineamiento de secuencias múltiples reveló que distintos géneros (Fusarium, Neocosmospora y Syncephalastrum) separados entre ellos y especies del mismo género se agrupan con sus secuencias de referencia con valores de bootstrap significativos. De cada 20 extractos representantes de cada agrupamiento y todos los grupos externos secuenciados, ocho fueron identificados molecularmente como Neocosmospora vasinfecta, dos como Fusarium acutatum, una como Syncephalastrum monosporum, una como Fusarium oxysporum y una como Fusarium. Los patógenos de estas leguminosas resistentes a sequías no están restringidos por la localidad ni por un hospedero específico. Fusarium solani que marchita el frijol de vaca y pudre la semilla de Vigna aconitifolia, F. oxysporum que marchita a Vigna aconitifolia, F. acutatum que marchita a Vigna unguiculata y Cyamopsis tetragonoloba, Fusarium sp. que pudre la semilla de Cyamopsis tetragonoloba, Neocosmospora striata que pudre la raíz de Vigna unguiculata y marchita a Cyamopsis tetragonoloba y, Syncephalastrum monosporum que pudre la raíz en Cyamopsis tetragonoloba, fueron identificados molecularmente como nuevos registros de patógenos fúngicos que causan daños en las raíces de leguminosas resistentes a sequías.

Screening and characterization of endophytic Bacillus and Paenibacillus strains from medicinal plant Lonicera japonica for use as potential plant growth promoters

Abstract A total of 48 endophytic bacteria were isolated from surface-sterilized tissues of the medicinal plant Lonicera japonica, which is grown in eastern China; six strains were selected for further study based on their potential ability to promote plant growth in vitro (siderophore and indoleacetic acid production). The bacteria were characterized by phylogenetically analyzing their 16S rRNA gene similarity, by examining their effect on the mycelial development of pathogenic fungi, by testing their potential plant growth-promoting characteristics, and by measuring wheat growth parameters after inoculation. Results showed that the number of endophytic bacteria in L. japonica varied among different tissues, but it remained relatively stable in the same tissues from four different plantation locations. Among the three endophytic strains, strains 122 and 124 both had high siderophore production, with the latter showing the highest phosphate solubilization activity (45.6 mg/L) and aminocyclopropane-1-carboxylic acid deaminase activity (47.3 nmol/mg/h). Strain 170 had the highest indoleacetic acid (IAA) production (49.2 mg/L) and cellulase and pectinase activities. After inoculation, most of the six selected isolates showed a strong capacity to promote wheat growth. Compared with the controls, the increase in the shoot length, root length, fresh weight, dry weight, and chlorophyll content was most remarkable in wheat seedlings inoculated with strain 130. The positive correlation between enzyme (cellulose and pectinase) activity and inhibition rate on Fusarium oxysporum, the IAA production, and the root length of wheat seedlings inoculated with each tested endophytic strain was significant in regression analysis. Deformity of pathogenic fungal mycelia was observed under a microscope after the interaction with the endophytic isolates. Such deformity may be directly related to the production of hydrolytic bacterial enzymes (cellulose and pectinase). The six endophytic bacterial strains were identified to be Paenibacillus and Bacillus strains based on the results of 16S rRNA gene sequencing analysis and their physiological and biochemical characteristics. Results indicate the promising application of endophytic bacteria to the biological control of pathogenic fungi and the improvement of wheat crop growth.

Manganese influx and its utilization efficiency in wheat.

Manganese deficiency in wheat has become an important nutritional disorder particularly in alkaline calcareous soils where rice-wheat rotation is followed. This experiment was aimed to study the mechanism of Mn efficiency during various developmental stages in six wheat cultivars grown at two Mn levels viz. 0 and 50 mg Mn kg-1soil (Mnapplied as MnSO4.H20) in pots. The Mn vegetative efficiency calculated on the basis of shoot dry weight at anthesis indicated HD 2967 and PBW 550 (bread wheat) as Mn efficient and durums as Mn inefficient. The efficient cultivars recorded highest values for influx, uptake, shoot dry weight, leaf area/plant, SPAD index, Fv/Fmratio and root length that explained their higher efficiencies whereas inefficiency of durum cultivars was attributed to their smaller roots and lower influx. Under Mn deficiency, PDW 314 and PDW 291 retained 68% and 64%, respectively, of total Mn uptake in vegetative parts (stem and leaves) and lowest in grains 7% and 5%, respectively, whereas PBW 550, BW 9178 and HD 2967 retained 29, 37 and 34% in vegetative parts, and 21, 17 and 15 % in grains, respectively at maturity. Higher utilization efficiency of efficient genotypes also indicated that increased Mn uptake with Mn supply produced more efficiently grains in efficient genotypes but vegetative parts in inefficient genotypes. Hence Mn efficiency of a cultivar could be explained by longer roots, higher uptake, influx and efficiency index during vegetative phase and higher grain yield and utilization efficiency during generative phase.

Response of aerobic rice to Piriformospora indica.

Rice cultivation under aerobic condition not only saves water but also opens up a splendid scope for effective application of beneficial root symbionts in rice crop unlike conventional puddled rice cultivation where water logged condition acts as constraint for easy proliferation of various beneficial soil microorganisms like arbuscular mycorrhizal (AM) fungi. Keeping these in view, an in silico investigation were carried out to explore the interaction of hydrogen phosphate with phosphate transporter protein (PTP) from P. indica. This was followed by greenhouse investigation to study the response of aerobic rice to Glomus fasciculatum, a conventional P biofertilizer and P. indica, an alternative to AM fungi. Computational studies using ClustalW tool revealed several conserved motifs between the phosphate transporters from Piriformospora indica and 8 other Glomus species. The 3D model of PTP from P.indica resembling “Mayan temple” was successfully docked onto hydrogen phosphate, indicating the affinity of this protein for inorganic phosphorus. Greenhouse studies revealed inoculation of aerobic rice either with P. indica, G. fasciculatum or both significantly enhanced the plant growth, biomass and yield with higher NPK, chlorophyll and sugar compared to uninoculated ones, P. indica inoculated plants being superior. A significantly enhanced activity of acid phosphatase and alkaline phosphatase were noticed in the rhizosphere soil of rice plants inoculated either with P. indica, G. fasciculatum or both, contributing to higher P uptake. Further, inoculation of aerobic rice plants with P. indica proved to be a better choice as a potential biofertilizer over mycorrhiza.

Androgenesis in chickpea: Anther culture and expressed sequence tags derived annotation.

Double haploid technique is not routinely used in legume breeding programs, though recent publications report haploid plants via anther culture in chickpea (Cicer arietinum L.). The focus of this study was to develop an efficient and reproducible protocol for the production of double haploids with the application of multiple stress pre-treatments such as centrifugation and osmotic shock for genotypes of interest in chickpea for their direct use in breeding programs. Four genotypes, ICC 4958, WR315, ICCV 95423 and Arearti were tested for anther culture experiments. The yield was shown to be consistent with 3-5 nucleate microspores and 2-7 celled structures with no further growth. To gain a further insight into the molecular mechanism underlying the switch from microsporogenesis to androgenesis, bioinformatics tools were employed. The challenges on the roles of such genes were reviewed while an attempt was made to find putative candidates for androgenesis using Expressed Sequenced Tags (EST) and interolog based protein interaction analyses.

Conservação e enraizamento in vitro de infalível (Mandevilla velutina K. Schum.), uma planta medicinal do Cerrado / In vitro conservation and rooting of "infalível" (Mandevilla velutina K. Schum.), a medicinal plant of Cerrado

Mandevilla velutina (Apocynaceae) é uma planta medicinal endêmica do Cerrado brasileiro conhecida popularmente como infalível, utilizada pela população em tratamentos de processos inflamatórios e acidentes com serpentes. Atualmente, esta espécie encontra-se em risco de extinção, devido à coleta extrativista. Os objetivos deste trabalho foram otimizar o protocolo para o enraizamento in vitro de M. velutina e introduzir diferentes genótipos em banco de germoplasma in vitro, a fim de se estabelecer a conservação da espécie. Foram realizados cinco experimentos de enraizamento in vitro utilizando ANA, AIB, di e poliaminas, dithiothreitol e floroglucinol. As avaliações foram realizadas aos 30 e 60 dias quanto à porcentagem de enraizamento, número e comprimento de raiz. Para a introdução dos genótipos in vitro, foram utilizados segmentos nodais (1 cm) como explantes, contendo uma gema axilar ou apical, coletados de plantas mantidas em casa de vegetação, submetidos previamente à assepsia. As avaliações foram realizadas durante quatro semanas, quanto à porcentagem de contaminação dos explantes. Os resultados obtidos nas avaliações evidenciaram que a presença de compostos fenólicos no meio de cultura foi importante na promoção do enraizamento adventício in vitro de M. velutina e a metodologia de assepsia para a introdução de diferentes genótipos in vitro foi eficiente.

Mandevilla velutina (Apocynaceae) is a medicinal plant endemic to the Brazilian Cerrado, commonly known as "infalivel" and used by the population for treatments of inflammatory processes and accidents with snakes. This species is currently endangered due to extraction. The aims of this study were to optimize the protocol for in vitro rooting of M. velutina and to introduce different genotypes in the in vitro germplasm bank to establish the species conservation. Five experiments for in vitro rooting were conducted using NAA, IBA, di and polyamines, dithiothreitol and phloroglucinol. Evaluations were performed at 30 and 60 days as to rooting percentage, and root number and length. For the introduction of genotypes in vitro, nodal segments (1 cm) were used as explants; they had an axillary or apical bud and were collected from plants kept in a greenhouse after being subjected to asepsis. Evaluations were carried out for four weeks as to the percentage of explant contamination. Results showed that the presence of phenolic compounds in the culture medium was important to promote in vitro adventitious rooting in M. velutina and that the asepsis methodology for the introduction of in vitro of different genotypes was efficient.

Ability of Allium cepa L. root tips and Tradescantia pallida var. purpurea in N-nitrosodiethylamine genotoxicity and mutagenicity evaluation

N-nitroso compounds, such as N-nitrosodiethylamine (NDEA), can be formed by the reaction of secundary amines with nitrosating agents, and are suspected to be involved in tumors in humans. NDEA has been considered a weak carcinogen in genotoxic assays probably due to the inefficient nitrosamine activation system that is used and/or to the efficient repair system. In this work, we evaluated the sensibility of Allium cepa L. root tips and Tradescantia stamen hair mutation assay (Trad-SH) using Tradescantia pallida var. purpurea for NDEA (0.1; 0.5; 5 and 25mM) genotoxicity and mutagenicity induction. Allium cepa L. was treated with different NDEA concentrations for 3h, for 3 consecutive days, including negative control (distilled water) and positive control maleic hydrazide (MH 30mg/mL). After treatment, the roots were hydrolyzed, squashed, and the mitotic index (MI) and cytological abnormalities were scored. The results revealed a cytostatic effect of NDEA (0.5 and 5mM), showing a significant reduction in the MI. Chromosome stickiness suggests a NDEA toxic effect. T. pallida purpurea did not respond to mutagens with a dose-dependent pattern. In conclusion, our study indicates that the root tips of Allium cepa L. have sensibility to detect NDEA genotoxicity, but not for Trad-SH test.

Nitrocompostos, como N-nitrosodietilamina (NDEA), podem ser formados pela reação entre uma amina secundária e agentes nitrosantes e são suspeitos de estarem envolvidos na formação de tumores em humanos. NDEA é considerada um carcinógeno fraco e ensaios genotóxicos provavelente pela utilização de um sistema de ativação ineficiente e/ou pela utilização de um eficiente sistema de reparo. Neste trabalho, nós avaliamos a sensibilidade de ensaios com Alliu cepa L. e Tradescantia pallida var. purpurea (Trad-SH) à genotoxicidade e mutagenicidade induzidas por diferentes concentrações de NDEA (0,1; 0,5; 5 e 25mM) por 3h, por 3 dias consecutivos, incluindo controle negativo (água destilada) e controle positivo, hidrazida maleica (MH 30mg/mL). Depois do tratamento, as raízes foram hidrolizadas, esmagadas e o índice mitótico (IM) e anormalidades citológicas foram contadas. Os resultados revelaram um efeito citostático de NDEA (0,5 e 5mM), pela significante redução do IM. Chromosome stickiness sugere um efeito citotóxico de NDEA. T pallida purpurea não respondeu ao mutágeno com um padrão dose dependente. Em conclusão, nossos estudos indicaram que raízes de Allium cepa L. possue sensibilidade na detecção genotóxica de NDEA, mas não para o ensaio Trad-SH.

Genotypic variation in morphology and freezing resistance of Eucalyptus globulus seedlings subjected to drought hardening in nursery / Variación genotípica en la morfología y resistencia a la congelación del Eucalyptus globulus a la sequía sometido al endurecimiento en vivero

Eucalyptus globulus Labill is one of the most planted species in Chile, because of its fast growth and superior pulp qualities. Nevertheless, the incidence of drought and frost damage immediately after planting is frequent. The purpose of this work was to study the effect of drought hardening on frost resistance and on variations in morphological traits that may increase drought resistance at nursery phase in four genotypes of E. globulus Labill. Drought hardening treatments consisted in induced water stress by watering restriction, until pre-dawn stem xylem water potentials (Psi pd) reached -0.2, -1.8 and -2.6 MPa. Two water stress-rewatering cycles were applied during 54 days of hardening. Plant and root biomasses were affected by the interaction of drought hardening and genotypes. The rest of morphological and alometrical traits were affected independently by drought or genotype. Plant height, leaf area, specific leaf area (SLA), stem, and leaf biomasses decreased with drought hardening, while collar diameter was not affected. Genotypes responded differentially to drought hardening in plant height, leaf area, SLA, and stem, and leaf biomasses. Ice nucleation temperature (INT), and freezing temperatures (FRT), and 50 percent freezing damage index of leaves (LT50) were affected by the interaction between drought hardening and genotypes. EG-13, EG-23 and EG-22 genotypes became freezing tolerant with drought hardening (-2.6 MPa). Additionally, EG-14 genotype increased its freezing resistance at -1.8 MPa. Therefore, freezing resistance levels and mechanism depend on genotype and drought hardening treatment. The success in tree breeding by genetic selection should be facilitated by improved understanding of the physiology of stress resistance development and survival during water supply limitations. The knowledge of morphological and freezing resistance dependency on the interaction between genotype and drought hardening may be useful...

PtSRR1, a putative Pisolithus tinctorius symbiosis related receptor gene is expressed during the first hours of mycorrhizal interaction with Castanea sativa roots / PtSRR1, um possível receptor simbiose-regulado de Pisolithus tinctorius é expresso nas primeiras horas de interação ectomicorrízica com raízes de Castanea sativa

PtSRR1 EST was previously identified in the first hours of Pisolithus tinctorius and Castanea sativa interaction. QRT-PCR confirmed PtSRR1 early expression and in silico preliminary translated peptide analysis indicated a strong probability that PtSRR1 be a transmembrane protein. These data stimulate the PtSRR1 gene research during ectomycorrhiza formation.

PtSRR1 foi isolado preliminarmente de P. tinctorius nas primeiras horas da interação com raízes de C. sativa. Análises de QRT-PCR confirmaram sua expressão positiva (12 h) e seu peptídeo putativo indicou forte possibilidade para proteína transmembranar. Estes dados estimulam o estudo do PtSRR1 durante a formação de ectomicorrizas.

Cytogenetical and ultrastructural effects of copper on root meristem cells of Allium sativum L

Different copper concentrations, as well as different exposure times, were applied to investigate both cytogenetical and ultrastructural alterations in garlic (Allium sativum L.) meristem cells. Results showed that the mitotic index decreased progressively when either copper concentration or exposure time increased. C-mitosis, anaphase bridges, chromosome stickiness and broken nuclei were observed in the copper treated root tip cells. Some particulates containing the argyrophilic NOR-associated proteins were distributed in the nucleus of the root-tip cells and the amount of this particulate material progressively increased with increasing exposure time. Finally, the nucleolar material was extruded from the nucleus into the cytoplasm. Also, increased dictyosome vesicles in number, formation of cytoplasmic vesicles containing electron dense granules, altered mitochondrial shape, disruption of nuclear membranes, condensation of chromatin material, disintegration of organelles were observed. The mechanisms of detoxification and tolerance of copper are briefly discussed.

Genetic transformation studies and scale up of hairy root culture of Glycyrrhiza glabra in bioreactor

The study was undertaken to induce hairy roots in Glycyrrhiza glabra in leaf explants and to optimize the nutritional requirement for its growth kinetics at shake flask and bioreactor level. Pathogenecity of Agrobacterium depends upon transformation ability of strain and age, type, and physiological state of explants. Agrobacterium rhizogenes strain K599 was used to infect leaf explants of G. glabra. Explants of different age groups were obtained from 2 to 5 weeks old in vitro grown cultures. Bacterial strain K599 could induce hairy roots in 3 and 4 weeks old leaf explants cultured on B5, MS, NB and WP basal semi-solid medium. Leaf explants of 2 and 5 weeks old culture were not responsive to bacterial infection in terms of hairy root induction. Maximum transformation frequency (TF) of tested bacterial strain was 47 percent obtained in 3 weeks old explants after 25 days of incubation on MS basal semi solid medium. NB and B5 both media composition showed 20 percent of transformation frequency after 28 and 38 days respectively. WP medium did not support induction of roots in cultured leaf explants infected with A. rhizogenes strain K599even after 50 days of incubation. Further, when all the four media combinations were tested for root growth it was found that though WP was not responsive for hairy root induction, yet all four basal media supported hairy root growth and a gradual increase in fresh weight biomass was observed with an increase in culture duration. However amongst all, the NB medium composition supported best growth of hairy roots followed by MS, B5 and WP media. About 20 times increase in root biomass on fresh weight basis was recorded after 45days of culture in NB medium. Initial inoculum of roots (0.18 g. F.wt./ flask) containing 50 ml of liquid culture medium produced 3.59 g (F. wt.) biomass. A fast growing hairy root clone G6 was grown in a 5 l capacity mechanically agitated bioreactor provided with a nylon mesh septum. After 30 days of sterile...

Chromosome number and cytogenetics of Euphorbia heterophylla L

Euphorbia heterophylla L. (Euphorbiaceae) is a herbaceous species of great economic importance due to its invasive potential and consequent damage to agriculture and pasture land. For the first time, we provide information on its chromosome number, morphology, and behavior of mitotic chromosomes. Seeds were germinated and submitted to four treatments to obtain metaphases: 0.5% colchicine for 2 to 5 h, at ambient temperature; 0.5% colchicine for 16 to 24 h; 0.0029 M 8-hydroxyquinoline (8-HQ) for 2 to 5 h at ambient temperature, and 0.0029 M 8-HQ for 16 to 24 h at 4°C. The material was then fixed in methanol:acetic acid (3:1) and kept at -20°C for 24 h. Roots were macerated in the enzyme solution of Flaxzyme™ (NOVO FERMENT™)-distilled water (1:40) at 34°C for 2 h and later fixed again. Chromosome preparations were obtained by the dissociation of the apical meristems. The best chromosome preparations were obtained with the use of 8-HQ for 21 h 30 min at 4°C. E. heterophylla showed 2n = 28 chromosomes. The short arm of the largest pair of chromosomes of the complement (pair number 1) displayed a secondary constriction while the nucleolus was observed in the interphasic cell. Structural rearrangements were also observed in the E. heterophylla L. genome. The genomic instability associated with polyploidy may be the result of selection shaped by environmental adaptations and/or human-induced manipulation through agricultural practices.

Candidate genes for drought tolerance and improved productivity in rice (Oryza sativa L.).

Candidate genes are sequenced genes of known biological action involved in the development or physiology of a trait. Twenty-one putative candidate genes were designed after an exhaustive search in the public databases along with an elaborate literature survey for candidate gene products and/or regulatory sequences associated with enhanced drought resistance. The downloaded sequences were then used to design primers considering the flanking sequences as well. Polymerase chain reaction (PCR) performed on 10 diverse cultivars that involved Japonica, Indica and local accessions, revealed 12 polymorphic candidate genes. Seven polymorphic candidate genes were then utilized to genotype 148 individuals of CT9993 x IR62266 doubled haploid (DH) mapping population. The segregation data were tested for deviation from the expected Mendelian ratio (1:1) using a Chi-square test (less than 1%). Based on this, four candidate genes were assessed to be significant and the remaining three, as non-significant. All the significant candidate genes were biased towards CT9993, the female parent in the DH mapping population. Single-marker analysis strongly associated (less than 1%) them to different traits under both well-watered and low-moisture stress conditions. Two candidate genes, EXP15 and EXP13, were found to be associated with root number and silicon content in the stem respectively, under both well-watered and low-moisture stress conditions.

Inheritance of resistance to Meloidogyne incognita race 2 in the hot pepper cultivar Carolina Cayenne ( Capsicum annuum L. )

Root-knot nematodes of the genus Meloidogyne are important pathogens affecting vegetable crop production in Brazil and worldwide. The pepper species Capsicum annuum includes both hot and sweet peppers; very little emphasis has been placed on breeding sweet peppers for nematode resistance. We report on the inheritance of resistance to Meloidogyne incognita (Kofoid & White) Chitwood race 2 in the hot pepper cultivar Carolina Cayenne. The hot pepper cv. Carolina Cayenne was used as seed parent and the sweet pepper cv. Agronômico-8 was used as pollen parent to obtain the F1 and F2 generations and the backcross generations BC11 and BC12. The plants were inoculated with M. incognita race 2 at a rate of 60 eggs/ml of substrate and, after a suitable incubation period, the numbers of root galls and egg masses per root system were evaluated on each plant. Broad- (0.77 and 0.72) and narrow-sense (0.77 and 0.63) heritability estimates were high for both root galls and egg masses, respectively. The mean degree of dominance was estimated as 0.29 and 0.25 for numbers of galls and egg masses, respectively; these estimates were not significantly different from 0, indicating a predominantly additive gene action. The results were consistent with a hypothesis of monogenic resistance in Carolina Cayenne.

Estudo farmacognóstico e farmacológico de Bredemeyera floribunda Willdenow / Bredemeyera floribunda Willdenow pharmacognostic and pharmacological study

Bredemeyera floribunda Willdenow, espécie vegetal vulgarmente conhecida como botica inteira, ocorre com freqüência nos campos cerrados do país. A botica inteira, cuja parte empregada são as raízes, é utilizada na medicina popular como expectorante, diurética, em problemas circulatórios e para baixar a pressão arterial. O estudo botânico detalhado das partes empregadas comercialmente foi efetuado e fotografias ilustram a tese. As características botânicas importantes na identificação da droga são: 1) características macroscópicas - as raízes possuem forma cilíndrica e coloração castanho-amarelada. Estrias bem evidentes podem ser observadas ao lado de cicatrizes arredondadas em forma de crateras...