Phenotypic diversity of Xanthomonas sp. mangiferaeindicae

Carbohydrate utilization profiles by means of the API (Appareils et Procédés d'Identification) system and sensitivity to antibiotics and heavy metal salts of 68 Xanthomonas sp. mangiferaeindicae strains isolated in nine countries from mango (Mangifera indica L.) and other genera of the Anacardiaceae were examined to assess the variability of the taxon. The strains could be separated into 10 groups according to Ward clustering. Apigmented strains isolated from the pepper tree [syn. Brazilian pepper] (Schinus terebenthifolius Raddi) could not be clearly differentiated from most apigmented strains isolated from mango. Yellow-pigmented strains isolated from mango in Brazil and Reunion Island, apigmented strains isolated from mango in Brazil and from ambarella in the French West Indies, clustered in distinct groups. The results are consistent with those of other studies, based on isozyme analysis of esterase, phosphoglucomutase and superoxide dismutase, and hrp-RFLP analysis; they indicate the need for a comprehensive taxonomic evaluation of xanthomonads associated with Anacardiaceae.     

Genomic Variability of the Xanthomonas Pathovar mangiferaeindicae, Agent of Mango Bacterial Black Spot

The genetic diversity of 138 strains of the Xanthomonas pathovar mangiferaeindicae, which were isolated from three different hosts (mango, ambarella, and pepper tree) in 14 different countries, was assessed with restriction fragment length polymorphism markers. An analysis of patterns obtained by hybridization with an hrp cluster probe from Xanthomonas oryzae pv. oryzae separated 11 of the strains from all of the other strains, which suggested that these 11 strains may not be Xanthomonas pv. mangiferaeindicae strains. Hybridization with an avirulence gene from X. oryzae pv. oryzae and a repetitive DNA fragment from Xanthomonas pv. mangiferaeindicae separated the remaining 127 strains into four groups that were consistent with both geographic and host origins. The group with the greatest diversity consisted of strains from Southeast Asia, where mango originated. Other groups and subgroups contained strains that were either from widely separated countries, which suggested that wide dissemination from a single site occurred, or from localized areas, which suggested that evolution of separate lineages of strains occurred. One group of strains contained only strains isolated from pepper trees in Reunion, indicating that pepper tree may not be an alternate host for Xanthomonas pv. mangiferaeindicae strains.     

Prevalence of Xanthomonas euvesicatoria on Pepper in Brazil

Bacterial spot, caused by Xanthomonas spp., is one of the major diseases of pepper in Brazil, causing considerable losses to crop productivity. The efficient management of the disease is hampered by the high variability of the causal agents. In Brazil, there is no knowledge of which species of Xanthomonas occurs on pepper. In this study, 59 strains of Xanthomonas spp. isolated from different pepper‐producing regions of Brazil were characterized by biochemical and molecular techniques. Results showed the prevalence of X. euvesicatoria as the causal agent of bacterial spot on pepper in Brazil.     

Assessment of root-associated paenibacillus polymyxa groups on growth promotion and induced systemic resistance in pepper

Twenty-nine P. polymyxa strains isolated from rhizospheres of various crops were clustered into five genotypic groups on the basis of BOX-PCR analysis. The characteristics of several plant growth-promoting factors among the isolates revealed the distinct attributes in each allocated group. Under gnotobiotic conditions, inoculation of pepper roots with P. polymyxa isolates significantly increased the biomass in 17 of total 29 treated plants with untreated plants. Experiments on induced systemic resistance (ISR) against bacterial spot pathogen Xanthomonas axonopodis pv. vesicatoria in pepper by P. polymyxa strains were conducted and only one isolate (KNUC265) was selected. Further studies into ISR mediation by the KNUC265 strain against the soft-rot pathogen Erwinia carotovora subsp. carotovora in tobacco demonstrated that the tobacco seedlings exposed to either bacterial volatiles or diffusible metabolites exhibited a reduction in disease severity. In conclusion, ISR and plant growth promotion triggered by P. polymyxa isolates were systemically investigated on pepper for the first time. The P. polymyxa KNUC265 strain, which elicited both ISR and plant growth promotion, could be potentially used in improving the yield of pepper and possibly of other crops.     

Production of wine from mango (Magnifera indica L.) using Saccharomyces and Schizosaccharomyces species isolated from palm wine

Juice extracted from pulp of the mature ripe tropical fruit, mango ( Magnifera indica L.), containing 15.9% soluble solids, was fermented with four strains of yeast isolated from palm wine. Two of the strains belonged to the genus Schizosaccharomyces (T1 and T2) while the other two were Saccharomyces (B2 and M1). The two strains of Schizosaccharomyces were found to be suitable for the production of sweet, table mango wine with alcohol contents of 8.0 and 9.0% for T1 and T2, respectively. The two strains of Saccharomyces were found suitable for the production of dry mango fruit wines containing 10.0% alcohol.     

Evaluation of the diversity of cyclodextrin-producing Paenibacillus graminis strains isolated from roots and rhizospheres of different plants by molecular methods

To address the diversity of cyclodextrin-producing P. graminis strains isolated from wheat roots and rhizospheres of maize and sorghum sown in Australia, Brazil, and France, restriction fragment length polymorphism analysis of part of genes encoding RNA polymerase (rpoB-RFLP) and DNA gyrase subunit B (gyrB-RFLP) was used to produce genetic fingerprints. A phylogenetic tree based on rpoB gene sequences was also constructed. The isolates originated from Brazil could be separated from those from Australia and France, when data from the rpoB-based phylogenetic tree or gyrB-RFLP were considered. These analyses also allowed the separation of all P. graminis strains studied here into four clusters; one group formed by the strains GJK201 and RSA19T, second group formed by the strains MC22.02 and MC04.21, third group formed by the strains TOD61, TOD 221, TOD302, and TOD111, and forth group formed by all strains isolated from plants sown in Cerrado soil, Brazil. As this last group was formed by strains isolated from sorghum and maize sown in the same soil (Cerrado) in Brazil, our results suggest that the diversity of these P. graminis strains is more affected by the soil type than the plant from where they have been isolated.     

<Emphasis Type="Italic">Scirtothrips dorsalis</Emphasis> (Thysanoptera: Thripidae): a Newly Introduced Polyphagous Pest in Northeastern Brazil

We report for the first time the detection of Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) in Brazil and describe the occurrence of the thrips on leaves of ungrafted dwarf-cashew Anacardium occidentale Linnaeus 1753 (Anacardiaceae), maintained into a greenhouse, in the northeastern state of Ceará. This exotic polyphagous species listed as absent quarantine pest in the country is originated in Asia, but since the beginning of this century, it has readily dispersed despite the strict quarantine regulations currently in several countries. Individuals of S. dorsalis identified in Brazil are similar to specimens found in South Africa rather than Asia by virtue of the absence of conspicuous reticulation on the posterior half of the metanotum and the presence of complete lines of microtrichia restricted to the posterior part of the abdominal sternites. Scirtothrips dorsalis is a particularly invasive pest and its introduction represents a potential threat to various crops in Brazil, especially mango.     

Strains of Xylella fastidiosa Rapidly Distinguished by Arbitrarily Primed-PCR

Genomic DNAs isolated from strains of Xylella fastidiosa that caused citrus variegated chlorosis, coffee leaf scorch, Pierce's Disease of grapevine, and plum leaf scorch were analyzed by arbitrarily primed polymerase chain reaction. Purified DNA was amplified under nonstringent conditions with single primers 21 nucleotides (nt) long. Thirty-nine amplification products were observed that were useful to distinguish among the strains and to derive a similarity matrix and construct a phenogram showing possible relationships among the strains. Strains isolated from diseased coffee and citrus in Brazil were closely related to each other (coefficient of similarity of 0.872), but only distantly related to a strain isolated from diseased grapevine in the USA (coefficient of similarity of 0.650). Strains of Xylella fastidiosa isolated from diseased plums in the USA and Brazil clustered with strains from different hosts isolated from their respective countries of origin. Thus, there may be two quite dissimilar clusters of strains of Xylella fastidiosa, one in North America and the other in South America. Each cluster contains strains that can cause disease in plum. The methods described provide a convenient and rapid method to distinguish between strains of Xylella fastidiosa that cause diseases of coffee and citrus in the same region of Brazil. This has not been possible previously. This will potentially enable the two strains to be distinguished in alternate hosts or in insect vectors. Received: 12 October 1999 / Accepted: 16 November 1999     

Randomly Amplified Polymorphic DNA (RAPD) and Isoenzyme Analysis of Trypanosoma rangeli Strains

ABSTRACT. Sixteen Trypanosoma rangeli strains were compared by isoenzyme and randomly amplified polymorphic DNA (RAPD) analysis. Eight strains were isolated from either Rhodnius prolixus or Homo sapiens from Honduras, Colombia and Venezuela. Another eight strains were isolated from either Panstrongylus megistus or the rodent Echimys dasythrix from the State of Santa Catarina, southern Brazil. All six T. rangeli strains isolated from P. megistus were co-infections with Trypanosoma cruzi , demonstrating an overlap of the sylvatic cycles of these parasites and that the accurate identification of species is of utmost importance. Both isoenzyme and RAPD analysis revealed two distinct groups of T. rangeli strains, one formed by the strains from Santa Catarina and the other, by the strains from Honduras, Colombia and Venezuela. With the five enzymes used, all the strains from Santa Catarina had identical profiles which overlapped with those of the other regions only in the pattern obtained with malic enzyme. Analysis of 138 RAPD bands by means of an unweighted pair group method analysis (UPGMA) phenogram using the Dice similarity coefficient allowed the separation of the two groups based on their divergence at a lower level of similarity than the phenon line. We show that the identification of T. cruzi and T. rangeli in naturally mixed infections is readily achieved by either RAPD or isoenzyme analysis.     

Attraction of the West Indian fruit fly to mango fruit volatiles

In this study, we investigated the attraction of West Indian fruit fly, Anastrepha obliqua (Macquart) (Diptera: Tephritidae), to volatiles of three mango [Mangifera indica L. (Anacardiaceae)] cultivars in field cage tests. The number of flies captured with Multilure traps baited with Amate mature green mangoes was significantly higher than that captured in traps baited with Coche and Ataulfo fruits. There was no significant difference between the number of flies captured in traps baited with Coche or Ataulfo mangoes. Gas chromatography‐mass spectrometry analysis of mango fruit volatiles identified 24, 22, and 19 compounds for Amate, Ataulfo, and Coche mango cultivars, respectively. A principal component analysis of the volatiles revealed that the Amate mango was more distant from the Ataulfo mango, and the latter cultivar was closer to the Coche mango. The compounds myrcene, α‐pinene, β‐selinene, and trans‐β‐ocimene were the most abundant in Amate mangoes, whereas 3‐carene, β‐selinene, terpinolene, and α‐pinene were the predominant compounds of Ataulfo cultivars. In the Coche mango, the predominant compounds were 3‐carene, β‐selinene, terpinolene, and limonene. Traps baited with a blend of myrcene, α‐pinene, and trans‐β‐ocimene captured more A. obliqua females and males than control traps. Flies were more attracted to the Super Q volatile extracts of Amate mango than to the three‐component blend formulated in a ratio of 1:1:1. However, there was no significant difference between the number of flies caught by traps baited with Amate mango extracts and that caught by traps baited with the three‐blend component when this was formulated according to the relative proportions in the mango extracts. Traps baited with myrcene, the major component, caught fewer flies than traps baited with Amate mango extracts.     

Tertiary leaf fossils of Mangifera (Anacardiaceae) from Li Basin, Thailand as examples of the utility of leaf marginal venation characters

The mango (Mangifera) is the most important commercial fruit in Asia and is popular worldwide. Because of uncertainty in its origin and biogeography, the study of Mangifera could be of value in elucidating its current genetic diversity and geographical distribution. We report here two new species of compressed leaves of Mangifera (Anacardiaceae) from upper Oligocene-lower Miocene lacustrine sediments in the Li Basin, northern Thailand. Leaf form and venation characters of fossil and extant leaves are presented with detailed marginal venation patterns that were found to be important in assigning the fossil leaves to Mangifera paleoindica and M. paleocaloneura. These two fossil species of Mangifera and the present occurrence of basal species of Mangifera in Thailand suggest that northern Thailand could be an area with a long history of evolution and diversification of Mangifera, particularly M. indica.     

First Occurrence of <Emphasis Type="Italic">Sternochetus mangiferae</Emphasis> (Fabricius) (Coleoptera: Curculionidae) in Brazil

Specimens of the mango stone weevil Sternochetus mangiferae (Fabricius) (Coleoptera: Curculionidae) were found in fruits of mango from a tree in the residential area of the Rio de Janeiro, RJ. This is the first report of the S. mangiferae in Brazil, currently regulated as an absent quarantine pest in the country. A taxonomist specialized in Curculionidae confirmed the identification based on morphological diagnostics characteristics. This detection is a relevant finding, because Brazil is a major producer and exporter of mango and the main areas of mango for exportation are located very far from this detection point. This pest damages seed and embryo of mango fruits and it causes reduction of fruit size and its premature dropping. The detection was notified to the Plant Health Department, division of the Brazilian Ministry of Agriculture, Livestock and Food Supply (MAPA), which is the National Plant Protection Organization of Brazil.     

胶孢炭疽菌的种内遗传多样性研究*

应用RAPD分析对广东不同果树上的胶孢炭疽菌的种内遗传多样性进行研究。结果表明:除部分芒果上的菌株外,20个来源于不同果树上的胶孢炭疽菌都以较高的相似系数聚为一个大群(群I)。说明尽管胶孢炭疽菌具有复合种的性质,但在一定的地理范围内,其遗传背景还是相近的,表现出种的典型特征。6个芒果菌株组成3个小群,且与群I的亲缘关系较远,其分类地位有待进一步明确。     

Genetic diversity of soft rot strains of Pectobacterium,isolated from different hosts,using ISSR marker

Pectobacteria are one of the most important groups of plant pathogenic bacteria and have been reported in many countries including Iran. Thirty-five Iranian strains of pectobacteria were isolated from potato, cabbage, sugar beet, pepper, carrot, onion, cucumber, turnip and tomato host plants cultivated in Fars province of Iran, in 2013. The genetic diversity among the strains was evaluated using ISSR marker. The tested strains were rod-shape, motile with peritrichous flagella, gram-negative, facultative anaerobes, oxidase-negative, catalase-positive, and were able to cause potato rot, while they could not induce hypersensitive reaction on tobacco leaves. Based on phenotypic criteria, the isolated strains were categorised into three groups. The strains of first, second and third groups were related to Pectobacterium carotovorum subsp. carotovorum, Pectobacterium betavascularum and Dickeya chrysanthemi, respectively. According to ISSR assay, the primers that used in this assay showed significant diversity among the strains and the specific primers GTGC4, GAGC4 and GTG5 confirmed the classification.     

A method for estimation of population densities of ice nucleating active Pseudomonas syringae in buds and leaves of mango

Active ice nucleation strains of Pseudomonas syringae pv. syringae have been associated with a necrotic disease in mango trees growing in Málaga (southern Spain). In this paper a simple multiple-tube test is described to estimate the number of active ice nucleation bacteria associated with plant tissues and, also from suspensions of isolated bacterial strains. This method is based on the most probable number technique developed for microbiological analysis of water. The tube test presented a higher detection sensitivity of active ice nuclei than the traditional drop-freezing test, because a larger amount of plant material could be analysed routinely. Both methods demonstrated a similar accuracy. A high correlation was obtained between the tube test-estimated number of ice nuclei and populations of Ps. syringae -like organisms enumerated on King's agar B.     

Laccase in Anacardiaceae

The presence of a typical laccase is demonstrated in the cavities of the secretory ducts of a number of species of the Anacardiaceae, including Mangifera indica and Schinus molle. In addition mango fruit contains catechol oxidase. The presence of laccase may be of chemotaxonomic value.     

银杏内生细菌的分离鉴定及抑菌活性初探

【目的】从银杏(Ginkgo biloba)茎叶中分离鉴定内生细菌, 测定其体外抑菌活性及对辣椒果疫病的防治效果。【方法】采用平板对峙法筛选出对辣椒疫霉菌(Phytophthora capsici)有拮抗作用的内生细菌, 并用平板对扣法测定其中一株防治效果较好的内生细菌产生的挥发性物质对辣椒疫霉菌生长的影响。通过生防菌液和病原菌孢子悬浮液喷雾接种辣椒果测定该菌株对辣椒果疫病的防治效果。基于形态特征、生理生化特性、16S rDNA和gyrA基因序列同源性分析鉴定该生防菌株。【结果】从银杏的茎和叶中分离获得9株内生细菌。平板对峙生长试验结果表明, 菌株W5对供试的辣椒疫霉菌、稻瘟病菌(Pyricularia grisea)、水稻纹枯菌(Rhizoctonia solani)、黄瓜枯萎病菌(Fusarium oxysporum)、荔枝霜疫霉菌(Peronophythora litchi)、荔枝酸腐菌(Geotrichum candidum)均有抑制作用, 其中对辣椒疫霉菌、稻瘟病菌和荔枝霜疫霉菌的抑菌效果显著, 抑菌率分别为88.9%、86.3%和90.2%。其产生的挥发性物质能明显抑制辣椒疫霉菌菌丝的生长。对辣椒采后果疫病的防治效果表明, 先喷雾接种W5菌悬液24 h后再接种辣椒疫霉病菌孢子悬浮液的防治效果最好, 可将辣椒果的保鲜期延长2?3 d。该菌株被鉴定为解淀粉芽胞杆菌(Bacillus amyloliquefaciens)。【结论】获得了一株对植物病原菌物有良好防治效果的银杏内生解淀粉芽胞杆菌W5, 对辣椒采后果疫病及其他病原真菌的防治具有潜在应用价值。     

RAPD analysis of the genetic diversity of mango (Mangifera indica) germplasm in Brazil

We evaluated genetic variability of mango (Mangifera indica) accessions maintained in the Active Germplasm Bank of Embrapa Meio-Norte in Teresina, Piauí, Brazil, using RAPDs. Among these accessions, 35 originated from plantings in Brazil, six from the USA and one from India. Genomic DNA, extracted from leaf material using a commercial purification kit, was subjected to PCR with the primers A01, A09, G03, G10, N05, and M16. Fifty-five polymorphic loci were identified, with mean of 9.16 ± 3.31 bands per primer and 100% polymorphism. Application of unweighted pair group method using arithmetic average cluster analysis demonstrated five genotypic groups among the accessions examined. The genotypes Rosa 41, Rosa 48 and Rosa 49 were highly similar (94% similarity), whereas genotypes Sensation and Rosa 18 were the most divergent (only 7% similarity). The mango accessions were found to have considerable genetic variability, demonstrating the importance of analyzing each genotype in a collection in order to efficiently maintain the germplasm collection.