Botryosphaeriaceae associated with Pterocarpus angolensis (kiaat) in South Africa

There have been several recent reports of Pterocarpus angolensis (kiaat) trees dying in South Africa, Zambia and Zimbabwe, where this tree is used in traditional medicine and is a valuable source of timber for woodcarving and furniture. A survey of material from diseased P. angolensis trees in South Africa yielded isolates of the Botryosphaeriaceae, an important fungal family known to cause a number of tree diseases. The aim of this study was to identify these Botryosphaeriaceae and to determine their pathogenicity to P. angolensis with branch inoculations. Seven species of the Botryosphaeriaceae were identified based on a combination of morphological characteristics and sequences from the ITS and EF-1α gene regions. Four of these represent undescribed taxa for which the names Pseudofusicoccum violaceum, P. olivaceum, Diplodia alatafructa and Fusicoccum atrovirens are provided. The remaining three species collected include Lasiodiplodia theobromae, L. pseudotheobromae and L. crassispora. Inoculation trials on tree branches showed that L. pseudotheobromae and one isolate of D. alatafructa differed significantly from control inoculations. The high levels of virulence and common occurrence of L. pseudotheobromae suggest that this species could play a role in tree dieback and death.     

Temporal and spatial variation of Botryosphaeriaceae associated with Acacia karroo in South Africa

The Botryosphaeriaceae are common and diverse members of fungal communities infecting woody plants. They are also increasingly being used as model organisms to understand patterns in the global movement of latent pathogens. The aim of this study was to consider the species richness of the Botryosphaeriaceae associated with the native Acacia (Vachellia) karroo across South Africa, and the variation of species at specific local sites over time. The diversity of these fungi associated with different tissues of this host plant was also considered. These questions were addressed by sampling healthy A. karroo from 23 sites in South Africa and by more intensive hierarchical sampling conducted at 40 sites in one area over 3 yr. In total, 13 species of the Botryosphaeriaceae were identified, including seven that were isolated only from the more intensively sampled area. There was a clear geographical influence, with some species occurring only in some parts of the country. Significant variation in the species richness over time for the intensively sampled area was found and there was no evidence of tissue specificity for this group of fungi in leaves, branches and branchlets. Results of pathogenicity trials showed highly variable lesion sizes for the isolated species in comparison to the control, with Sphaeropsis variabilis, Lasiodiplodia theobromae and Neofusicoccum australe being the most pathogenic. The overall results revealed a rich diversity of Botryosphaeriaceae on this native host, which varied significantly both geographically and on individual trees, even in the absence of obvious disease.     

Airborne fungi associated with ornamental plant propagation in greenhouses

The objective was to determine potential exposure to airborne fungi in greenhouses and to characterize the temporal patterns of airborne fungi in relation to environmental conditions. We analyzed air samples collected in two greenhouses. Results showed that the top 5 fungi in greenhouse 1 were Trichoderma, hyphal fragments, Aspergillus/Penicillium-like, Cladosporium, and Botrytis in a descending order. Those in greenhouse 2 were Aspergillus/Penicillium-like, Cladosporium, Botrytis, yeast-like, and hyphal fragments. Maximum concentrations of Trichoderma and total spores in greenhouse 1 were 36,426 and 49,729 spores/m³, respectively. Maximum concentrations of Aspergillus/Penicillium and total spores in greenhouse 2 were 46,961 and 71,037 spores/m³, respectively. Airborne fungal populations fluctuated dramatically within 2 h during work hours, tenfold for Aspergillus/Penicillium, 66-fold for Trichoderma, and sevenfold for total spores. QPCR detected Trichoderma harzianum ranging from 7 to 3,500 conidia E/m³. Aspergillus/Penicillium and Botrytis showed diurnal patterns, but not Trichoderma. Aspergillus/Penicillium and Cladosporium were positively correlated with temperature, relative humidity, dew point, heat index, and light and negatively with air movement and air pressure. Botrytis and Trichoderma were not correlated with the environmental factors. Greenhouse workers were potentially exposed up to 71,037 spores/m³ of airborne fungi.     

Genetic variation of European grayling (Thymallus thymallus) populations in the Western Balkans

In order to elucidate genetic composition of European grayling (Thymallus thymallus) populations in the Western Balkans, the partial mitochondrial DNA (mtDNA) control region was sequenced and 12 microsatellite loci genotyped in 14 populations originating from tributaries of the Adriatic and Danube drainages. Eleven mtDNA haplotypes were found, one confined to the Adriatic clade, one to the Alpine group and the rest to the ‘Balkan’ grayling phylogenetic clade. Haplotypes from the Balkan clade were confined to the Danube drainage and constituted two groups: northern group with haplotypes found in the Slovenian part of the Danube drainage, and southern group, consisting from Bosnia–Herzegovina and Montenegro. Substantial genetic distance between northern and southern groups of haplotypes (0.75–1.8%) and well supported divisions within the northern group indicate very structured grayling population within the studied Danube basin that most probably did not evolve due to vicariance but rather as a consequence of multiple colonization waves that might have occurred during the Pleistocene. Furthermore, genetic distance of ~4% between Adriatic and Danube populations’ haplotypes, suggest that their separation occurred in mid-Pliocene. These findings imply a complex colonization pattern of the Western Balkans drainages. Microsatellite data also confirm high genetic diversity in Western Balkans populations of grayling (on average 7.5 alleles per microsatellite locus and H _exp 0.58). Limited stocking activities were detected based on microsatellites and mtDNA data. Regarding current knowledge of grayling phylogeography appropriate management strategies were proposed to preserve unique, autochthonous grayling populations in Western Balkan.     

Nematodes associated with forest and woodland trees in Scotland

A survey of the nematode genera associated with trees in Scotland showed that Tylenchus sensu lato, Aphelenchoides, Tylencholaimus, Trichodorus, Helicotylenchus, Rotylenchus, Criconemoides s.l., Hemicriconemoides, Tylencho-rhynchus, Pratylenchus and Paratylenchus s.l. were commonly found in soil samples collected from around the roots of coniferous and deciduous trees. Only Criconemoides s.l. appeared to have a significant preference for deciduous woods. The presence of undergrowth in woods and forests was associated with significantly greater numbers of plant-parasitic nematodes. Measurements of abiotic factors indicated that, in mineral soils, pH affected the incidence of most genera, but soil type, moisture content and altitude had little effect.     

Y-Haplotype X in the Balkans

A total of 2110 unrelated European male subjects were examined for the p49a,f TaqI Y-haplotype X. The results showed a remarkable mean peak of haplotype X frequencies (46.9%) among subjects from Croatia, and similar elevated frequency values were also found in their counterparts from Slovenia (41.5%), Bosnia (40.3%) and ex-Yugoslavia (36.7%). Frequencies of haplotype X decrease towards west (from 41.5% in Slovenia to less than 1% in northern Italy) and south (23.5% in Albania, 15.9% in Serbia, 7.5% in Greece and 2.1% in Crete), but retain relatively high frequencies in Romania (17.9%) and in Bulgaria (16.1%). Historical and genetic evidence allows us to demonstrate that haplotype X originated in Europe among descendants of men who have been associated with the Gravettian culture. During the Last Glacial Maximum the Western Balkan Peninsula constituted a “refuge” for haplotype X, the starting point of an expansion that spread this haplotype around the neighbouring populations in historical times.     

Variability of phytoplasma associated with few ornamental crop species in Uttar Pradesh,India

Abstract

The economic importance of ornamentals has been advancing significantly in many countries due to continuous international demand. Like other crops, ornamental plants are also affected by a number of pathogens and the phytoplasmas diseases are equally important group of pathogens which is responsible for damaging the different ornamental plant species and thereby affecting their market value. In the present investigation, total 24 symptomatic leaf samples of 8 ornamental plant species (C. roseus, R. rubiginosa, C. variegatum, Z. elegans, J. gendurusa, T. erecta, H. rosa sinensis, J. sambrac) were analyzed which were found positive in nested PCR assays with R16F2n/R16R2 primers. The phytoplasma associated with ornamental plant species collected from different districts of UP in the present investigation are belongs to 16Sr I, II, VI and XIV group.     

Tubular structures associated with mycoplasma in proliferation infected apple trees

Tubular structures showing honeycomb-like appearance in cross sections were found in mycoplasma invaded sievetube cells of abnormal sprouts of apple trees infected with the proliferation disease. The nature of tubular structures is unknown. There is a striking similarity (or identity) with the tubular structures described formerly in HEp-2 cells which were established from human carcinoma of the larynx.     

Bacterial Diversity among the Sediments of Glacial Lakes in the Western Balkans: Exploring the Impact of Human Population

16S rRNA gene-based metagenomic approach was used to assess the biodiversity of bacterial communities in the sediments of selected glacial lakes in the Western Balkans and to assess the impact of human population on these microbial communities. Sediment samples were collected from three glacial lakes, viz., Plav Lake (in a zone of the highest impact of human population), Black Lake (a zone of medium impact of human population), and Donje Bare Lake (a remote lake with minimal impact of human population).

Canonical correlation analysis analysis indicated correlation between the distance of the lake from urbanized population and bacterial diversity in Donje Bare Lake sediment. Bacterial diversity of Black Lake sediment was correlated with high content of phosphorous and pH value. Chemical compounds exhibiting the most prominent correlation with bacterial diversity of Plav Lake were NH₄-N, K₂O, CaCo₃, and total nitrogen . Additionally, CCA analysis indicated that population density was correlated with biodiversity of bacterial communities in Plav Lake sediment, which is the most exposed to human population. Multivariate regression revealed the highest correlation between the presence of Proteobacteria classes and population density and levels of NH₄-N.

The influence of human population was observed to be important for shaping the sediment communities in addition to biological and chemical factors.     

Monoterpene emissions from ornamental trees in urban areas: a case study of Barcelona, Spain

Research on biogenic volatile organic compound (BVOC) emissions has mainly focused on native species in natural ecosystems. However, much of the ozone and aerosol formation occurs in city atmospheres due to BVOC emissions by local urban vegetation. Plant composition of urban habitats is often dominated by non-native ornamental plant species, for which only limited data on BVOC emissions are available. To gain insight into the influence of ornamental vegetation on the urban atmospheric reactivity in Barcelona, Spain, we studied volatile isoprenoid emissions in 11 widespread ornamental tree species (three conifers and nine angiosperms). We found significant monoterpene emissions in all studied species, with normalized emission potentials (T=30 degrees C, photosynthetic photon flux density (PPFD)=1000 micromol x m(-2) x s(-1)) ranging between 0.2 to 110 microg x g(-1) (dry weight) h(-1). Depending on species, the emissions were dominated by alpha- and beta-pinene, myrcene, alpha- and beta-phellandrene, carene, limonene and eucalyptol. These data demonstrate that ornamental plants may significantly contribute to the BVOC load in urban atmospheres and also underscore the importance of broadleaf angiosperms as significant monoterpene emitters.     

Plant parasitic nematodes associated with ornamental plant Pseuderanthemum atropurpureum in Aligarh district of western Uttar Pradesh

A survey was conducted to determine the nematodes associated with the soil, substratum and roots of the ornamental plant, Pseuderanthemum atropurpureum, grown in the Aligarh district of western Uttar Pradesh, India. Ten genera of plant parasitic nematodes, viz. Meloidogyne spp., Helicotylenchus sp., Hemicriconemoides sp., Hoplolaimus sp., Xiphinema sp., Pratylenchus sp., Trichodorus sp., Tylenchorhynchus sp., Aphelenchoides sp. and Rotylenchus sp., were isolated from 345 soil samples collected from 15 different localities. Our study indicates that among the 10 genera of the plant parasitic nematodes, Meloidogyne spp. was widely spread in all the examined localities of Aligarh district, except at Khair. It was observed that the population density and diversity of nematodes in all the soil samples was not uniform. Meloidogyne spp. showed the highest absolute frequency and relative frequency followed by Helicotylenchus sp., Hemicriconemoides sp., Xiphinema sp., Hoplolaimus sp., Pratylenchus sp., Trichodorus sp., Tylenchorhynchus sp., Aphelenchoides sp. and Rotylenchus sp. Since no records are available in the literature related to the association of root-knot nematode in P. atropurpureum, it is worthy to note that this study may be considered as a new hope towards further study of the interaction between the root-knot nematode and ornamental plant P. atropurpureum if any.     

危害园林树木扶桑的粉蚧调查和形态鉴定

扶桑因花期长、颜色艳丽和便于栽种管理,是我国华南等热带地区普遍种植的重要园林植物。本文通过野外调查,采集了扶桑等寄主植物上发生危害的3种粉蚧,分别是扶桑绵粉蚧、木槿曼粉蚧和美地绵粉蚧。通过制作玻片标本,从足、刺孔群、盘孔、和管腺等部位详细比较了3种粉蚧的玻片主要显微特征以及野外活虫虫体特征,为基层农林工作人员识别该类害虫提供参考。     

Endomelanconiopsis, a new anamorph genus in the Botryosphaeriaceae

A new lineage is discovered within the Botryosphaeriaceae (Ascomycetes, Dothideomycetes, incertae sedis). Consistent with current practice of providing generic names for independent lineages, this lineage is described as Endomelanconiopsis gen. nov., with the anamorphic species E. endophytica sp. nov. and E. microspora comb. nov. (= Endomelanconium microsporum). Endomelanconiopsis is characterized by eustromatic conidiomata and holoblastically produced, brown, nonapiculate, unicellular conidia, each with a longitudinal germ slit. Phylogenetic analysis of partial sequences of LSU, ITS and translation elongation factor 1 alpha (tef1) indicate that E. endophytica is sister of E. microspora and that they are nested within the Botryosphaeriaceae. However because there is no support for the "backbone" of the Botryosphaeriacae we are not able to see the interrelationships among the many genera in the family. Neither species is known to have a teleomorph. Endomelanconiopsis differs from Endomelanconium because conidia of the type species of Endomelanconium, E. pini, are papillate at the base, conidiogenous cells proliferate sympodially and the pycnidial wall is thinner; we postulate that the teleomorph of E. pini as yet unknown is an inoperculate discomycete. Endomelanconiopsis endophytica was isolated as an endophyte from healthy leaves of Theobroma cacao (cacao, Malvaceae) and Heisteria concinna (Erythroplaceae) in Panama. Endomelanconiopsis microspora was isolated from soil in Europe.     

Red Data List of Charophytes in the Balkans

The occurrence of 47 species of all the six recent genera of charophytes recorded in the Balkans is demonstrated. Our aim was to assess their status of threat according to the 2001 IUCN threat categories and criteria, in order to establish the Red List of Charophytes distributed in the Balkan Peninsula. The List underlines the diversity of charophytes in this part of the world and provides guidelines for its conservation. Analysis of the charophytes in each category of threat has provided a general overview of their distribution, species richness, population features and possibility of survival throughout the various regions of the Balkan Peninsula.