Różnorodność grzybów powodujących brudną plamistość jabłek w Polsce

Sooty blotch is one of the most common disease of apples in organic orchards in many countries. Results of molecular studies performed in USA indicated approximately 30 different fungi species associated with this disease. Fungi species causing sooty blotch in Northern, Central and Eastern Poland were identified on the basis of morphology and nucleotide sequence of the rDNA internal transcribed spacer region (ITS). A total 245 isolates were collected in spring and early summer in the years 2006–2009 from fruits with visible symptoms of the disease. Isolates were grown on PDA medium and identified on the basis of morphological characters. DNA was extracted from representative isolates and used as matrices for PCR amplification with ITS1F and ITS4 primers. Fragments of amplified rDNA ITS were sequenced. It was found that 66.53% of all isolates causing sooty blotch were species from genera Microcyclosporella, followed by Aureobasidium pullulans – 22.86%, Microcyclospora sp. – 6.12%, Phialophora sessilis – 3.67%, Peltaster sp. and P. fructicola – 0.41%.Brudna plamistość jabłek jest powszechnie występującą chorobą owoców w sadach ekologicznych w wielu krajach. Wyniki badań molekularnych przeprowadzone w USA wykazały, że sprawcami tej choroby może być około 30 różnych gatunków grzybów. Celem pracy było określenie składu populacji grzybów powodujących brudną plamistość jabłek w centralnej, wschodniej i północnej Polsce z wykorzystaniem techniki PCR i tradycyjnych metod. Latem i wczesną wiosną w latach 2006–2009 z owoców z widocznymi objawami choroby uzyskano 245 izolatów grzybów – sprawców brudnej plamistości jabłek. Na podstawie cech morfologicznych izolaty grzybów rosnące na PDA wstępnie podzielono na 6 grup, a następnie z wybranych izolatów reprezentujących daną grupę wyizolowano DNA i zsekwencjonowano. Amplifikację DNA przeprowadzono za pomocą techniki PCR z wykorzystaniem starterów ITS1F i ITS4. Spośród uzyskanych izolatów sprawców brudnej plamistości najliczniejszą grupę stanowiły grzyby należące do rodzaju Microcyclosporella (66,53%). Pozostałe grzyby to: Aureobasidium pullulans – 22,86%, Microcyclospora sp. – 6,12%, Phialophora sessilis – 3,67% oraz Peltaster sp. i P. fructicola – 0,41%

Efficacy of biochemical preparations and extract from Hypericum perforatum against bacterial diseases

The biotechnical preparations: Biosept Active (based on a grapefruit extract) and BioZell (based on thyme oil) as well as Hypericum perforatum extract, streptomycin solution and fungicide Champion 50WP (active ingredient substance – e.i. 50% copper hydroxide) were investigated for antimicrobial effects against plant pathogenic bacteria: Agrobacterium tumefaciens, Pseudomonas syringae pv. syringae and Xanthomonas arboricola pv. corylina. The screening was carried out in vitro on three media: Nutrient Agar (NA Difco), Pseudomonas Agar F (Merck) – analogue of King B and 523. In the experiments, the agar plate method was applied. There were no statistically significant differences in the effect of streptomycin and Champion 50WP on the growth inhibition of three bacteria strains for medium 523 and Nutrient Agar and of P. syringae pv. syringae and X. arboricola pv. corylina for medium King B. It was determined that the antibacterial activity of Biosept Active and BioZell biopreparations and H. perforatum extract against Agrobacterium tumefaciens (strain C58), Pseudomonas syringae pv. syringae (strain 760) and Xanthomonas arboricola pv. corylina (strain RIPF-x13) were dependent on the strain of pathogen as well as the growth medium used. According to the research results obtained, the Biosept Active preparation and H. perforatum extract demonstrated high bacteriostatic activity against three bacterial strains grown on the Nutrient Agar medium

Characteristics of Valdensia heterodoxa Peyr. as an Ericaceae pathogen in Poland

Valdensia heterodoxa as a parasitic fungus was observed on Ericaceae family plants i.e. blueberry (Vaccinium corymbosum L.), bilberry (V. myrtillus L.) and lingonberry (V. vitis-idaea L.). Isolates of this polyphagous were obtained from the infected leaves of different cultivars of highbush blueberry collected from commercial plantation in Mazovia province and from bilberry collected from forests in Pomerania province. PCR amplification of selected rDNA fragments (ITS1, 5.8S, ITS2) was done with ITS1F and ITS4A primers. Bioinformatic analysis revealed similarity 99–100% between selected nucleotide sequences of V. heterodoxa isolates from bilberry and highbush blueberry. The sequences of bilberry isolates were obtained and described for the first time in Poland. Their reference sequence was deposited in GenBank (KT121733). In laboratory experiments conidia of selected bilberry isolates on OA medium were 278 ±6 × 140 ±4 μm. Conidia from highbush blueberry, bilberry, and lingonberry were measured. Depending on the host plant conidia were different in the length of the arms and width of the head. The growth of the fungal isolates on PDA (potato dextrose agar), OA (oatmeal agar), WOA (weak oatmeal agar), SNA (salt nutrient agar) media was examined. The cultures were divided into two groups based on their morphology on PDA medium

Charakterystyka grzyba Aureobasidium pullulans (de Bary et Lowenthal) G. Arnaud wyizolowanego z jabłek i gruszek z objawami brudnej plamistości w Polsce

Sooty blotch is a disease of apple and pear caused by a complex of fungi that blemish the fruit surface. Results of molecular studies indicated approximately 30 different fungi species associated with this disease. Apples and pears with symptoms of sooty blotch were collected in summer and early autumn 2006–2010 from trees grown in fungicide non-treated orchards and small gardens located in various regions of Poland. Fungi causing sooty blotch were isolated from fruits and the isolates were divided into six groups, according to their morphological characters. Growth of the fungi colonies were tested on different agar media (PDA, CMA, MEA and Czapek). The ITS region of rDNA from 16 isolates from the first group was amplified by PCR technique and one representative sequence of this isolates was used to alignment in Gene Bank. This isolate was identified as Aureobasidium pullulans and isolates from this group were compared with it on the base of morphological features.Przyczyną brudnej plamistości jabłek i gruszek jest kompleks grzybów powodujących oszpecenie powierzchni skórki owoców. Wyniki badań molekularnych wskazują, że z tą chorobą wiąże się ponad 30 różnych gatunków grzybów. Jabáka i gruszki z widocznymi objawami brudnej plamistości jabłek zbierano z niechronionych chemicznie sadów i ogródków działkowych w różnych regionach Polski. Owoce byáy zbierane latem i wczesną jesienią w latach 2006–2010. Z plam znajdujących się na owocach wyizolowano sprawców brudnej plamistości jabłek i na podstawie charakterystyki cech morfologicznych uzyskanych izolatów grzybów podzielono je na sześć grup. Badano również wzrost i wygląd kolonii grzybów na różnych podłożach (PDA, CMA, MEA i Czapek). Wyizolowano, a następnie zamplifikowano za pomocą techniki PCR z wykorzystaniem starterów ITS1F i ITS4, genomowe DNA 16 izolatów należących do pierwszej grupy. Grzyb ten został zidentyfikowany jako gatunek Aureobasidium pullulans, a jego zsekwencjonowane izolaty stanowiły wzorzec przy identyfikacji pozostałych izolatów zaklasyfikowanych do tej grupy

Fusarium spp. on the above-ground organs of dying oaks – a new threat?

Oak decline is insufficiently described problem. Declining oaks are in various age and the most commonly observed symptoms of the disease include growth inhibition and buds mortality. The dieback occurs periodically, mainly because of the impact of abiotic factors (drought, frost and the lowering of the groundwater level). In this complex phenomenon the biological factors, including numerous species of Chromista (Chromalveolata) and fungi play important role as well. The list of pathogens responsible for the dieback includes numerous species of Pythium and Phytophthora, as well as Biscogniauxia, Discula, Pleurophoma, Botryosphaeria and Diplodia. Among other organisms responsible for the oak decline are fungi belonging to Fusarium species. The aim of this study was to investigate the species composition of pathogens colonizing the dying oak buds including undeveloped or dying shoots obtained from Łomża, Rudka and Czarna Białostocka forest districts (eastern Poland). Sampling of symptomatic shoots of Quercus robur L. was performed in 2013, respecting different parts of tree crowns (top, central and bottom). Mycological material for analysis included mycelium growing on dying shoots after incubation in a chamber and tissue collected from symptomatic shoots and placed on PDA medium. For selected isolates of fungi the identification was confirmed by the PCR analysis using ITS1 and ITS4 primers. Among analyzed fungi Fusarium spp., Alternaria alternata, Cladosporium cladosporioides, Botryosphaeria quercuum and /em>Coniothyrium spp. required special attention. The Fusarium spp. group of fungi dominated with an average frequency of 32%. The molecular analysis revealed the presence of several species including Fusarium avenaceum, Cladosporium cladosporioides, Lophiostoma corticola and Nectria mauritiicola

The activity of essential oils obtained from species and interspecies hybrids of the Mentha genus against selected plant pathogenic bacteria

Plant essential oils of six aromatic herb species and interspecies hybrids of the family Lamiaceae – chocolate mint (Mentha piperita × ‘Chocolate’), pineapple mint (Mentha suaveolens ‘Variegata’), apple mint (Mentha × rotundifolia), spearmint (Mentha spicata), orange mint (Mentha × piperita ‘Granada’) and strawberry mint (Mentha × villosa ‘Strawberry’) – were investigated for antimicrobial effects against plant pathogenic bacteria: Agrobacterium tumefaciens, Pseudomonas syringae pv. syringae and Xanthomonas arboricola pv. corylina. The screening was carried out in vitro on agar plates filled with the target organism. All essential oils screened exhibited a higher level of antibacterial activity against A. tumefaciens and X. arboricola pv. corylina than streptomycin used as a standard in all tests. The antimicrobial effect of streptomycin and five mint oils was at the same level for P. syringae pv. syringae. There were no significant differences in the influence of the chocolate mint oil on the growth inhibition of all bacteria tested. Plant essential oils from pineapple mint, apple mint, spearmint and strawberry mint showed the weakest antimicrobial activity against P. syringae pv syringae and the strongest towards A. tumefaciens and X. arboricola pv. corylina. The essential oils from strawberry mint, pineapple mint, spearmint and apple mint had the strongest effect on A. tumefaciens, and the lowest inhibitory activity was exhibited by the chocolate mint and orange mint essential oils. X. arboricola pv. corylina was the most sensitive to the strawberry mint, pineapple mint and spearmint oils. The chocolate mint oil showed the greatest activity against P. syringae pv. Syringae

The risks of sweet corn and popcorn contamination by fumonisin FB1 produced due to Fusarium verticillioides infection

Based on two-year experiments on inoculated corn, including genotypes of sweet corn (Zea mays var. saccharata) and popcorn (Zea mays var. everta), the analysis of fumonisin FB1 content in kernels was performed. Infection degree of sweet corn was 2.00 and 2.13, which was distinctly stronger than infection of popcorn cobs (0.52 and 1.05). Despite of higher disease rating of Zea mays var. saccharata, the most dynamic increase in fumonisin FB1 biosythesis was observed in kernels of Zea mays var. everta. During the two cropping seasons, the mean level of FB1 in sweet corn ranged from 0.52 to 6.94 µg g–1, while in popcorn kernels from 0.96 to 28.49 µg g–1 in the 1st and 8th week after inoculation. Botanical varieties of maize as well as physiological state of kernels, determined by the water, amylose and starch contents, influenced on infection degree by Fusarium verticillioides and level of ear contamination by fumonisin FB1. Efficiency of biosynthesis of mentioned metabolites was inversely proportional to kernel water content

Fungi associated with black mould on baobab trees in southern Africa

There have been numerous reports in the scientific and popular literature suggesting that African baobab (Adansonia digitata) trees are dying, with symptoms including a black mould on their bark. The aim of this study was to determine the identity of the fungi causing this black mould and to consider whether they might be affecting the health of trees. The fungi were identified by sequencing directly from mycelium on the infected tissue as well as from cultures on agar. Sequence data for the ITS region of the rDNA resulted in the identification of four fungi including Aureobasidium pullulans, Toxicocladosporium irritans and a new species of Rachicladosporium described here as Rachicladosporium africanum. A single isolate of an unknown Cladosporium sp. was also found. These fungi, referred to here as black mould, are not true sooty mould fungi and they were shown to penetrate below the bark of infected tissue, causing a distinct host reaction. Although infections can lead to dieback of small twigs on severely infected branches, the mould was not found to kill trees.Members of the Tree Protection Co-operative Programme (TPCP), the NRF-DST Centre of Excellence in Tree Health Biotechnology (CTHB), and the University of Pretoria, South Africa.http://link.springer.com/journal/104822016-05-03hb201