6 research outputs found
Efficacy of fungicides and essential oils against bacterial diseases of fruit trees
In the framework of the performed studies, the antibacterial activity of the following fungicides was evaluated: Miedzian 50 WG (active substance - a.s. 50% copper oxychloride), Ridomil MZ Gold 68 WG (a.s. 3.8% metalaxyl-M and 64%, mancozeb), Euparen Multi 50 WG (a.s. 50% tolylfluanid), Captan 80 WG [a.s. 80% N-(captan)], Dithane Neotec 75 WG (a.s. 75% mancozeb). The evaluation also concerned the essential oils: lavender, sage, lemon balm, clove, and a preparation based on thyme oil (BioZell). Each preparation and compound was tested against the following bacterial pathogens: Erwinia amylovora, Xanthomonas arboricola pv. corylina, X. arboricola pv. juglandis, Pseudomonas syringae pv. syringae, Agrobacterium tumefaciens (presently Rhizobium radiobacter). Each preparation and compound was tested at a concentration of 1,000 ppm of active substance. Copper oxychloride was also tested at a concentration of 1,500 ppm. Among the tested fungicides, metalaxyl-M with mancozeb, mancozeb alone, and copper oxychloride inhibited all of the tested strains of pathogenic bacteria. Tolylfluanid did not inhibit any of the bacteria used. Out of the investigated essential oils, the strongest inhibitors of bacteria were: sage, cloves, and BioZell.
The protective activity of the above mentioned fungicides was also evaluated in vivo. They were assessed against fire blight on apple blossoms and pear fruitlets, against bacterial canker on sweet cherry fruitlets, and against crown gall on sunflower seedlings (the test plant). All fungicides were applied at the same concentrations as those in the in vitro tests. Only copper oxychloride was found to show protective activity against the studied diseases. This result indicates that the antibacterial properties of the other fungicides did not correspond with their activity on the plant organs used in the in vivo experiment
Izolacja, wstępna charakterystyka i wykrywanie bakterii zanieczyszczających kultury roślinne in vitro
In order to limit the contamination problem in plant
tissue cultures experiments on selection of media suitable for
detection and isolation of bacteria contaminating plant tissue
explants, and preliminary characterization of isolates were
made. In the first experiment aiming at detection of bacteria in
plant explants four strains representing genera most often occurring
at our survey of plant tissue cultures, and earlier isolated
and identified (Bacillus, Methylobacterium, Pseudomonas
and Xanthomonas) were streaked on five bacteriological media
(NA, King B, K, R2A and 523) and on the medium used for
plant culture initiation – 1 MS with milk albumin (IM). All strains
grew on all media but on K and IM at the slowest rate and on
523 medium at the fastest. The IM medium proved to be useful
for immediate bacteria detection at the initial stage of culture.
In the second experiment, aiming at characterization of isolates
on the basis of colony growth and morphology 14 strains
(Agrobacterium, Bacillus, Curtobacterium, Flavobacterium,
Lactobacillus, Methylobacterium – 2 strains Mycobacterium,
Paenibacillus, Plantibacterium, Pseudomonas, Stenotrophomonas,
Xanthomonas, and species Serratia marcescens) were
streaked on five microbiological media: KB, NBY, YDC, YNA
and YPGA. All strains grew on all those media but at different
rates. The only exception was the strain of Lactobacillus spp.,
which did not grow on King B medium. This medium allowed
the detection of such characteristic traits as fluorescence (Pseudomonas)
and secretion of inclusions (Stenotrophomonas). The
third experiment was focussed on assessment of the sensitivity
of detection of specific bacteria in pure cultures and in plant tissue
cultures using standard PCR and BIO-PCR techniques with
genus specific primers and 2 methods of DNA isolation. Results
showed that the use of Genomic Mini kit enabled an increase of
the sensitivity by 100 times as compared to extraction of DNA
by boiling. Moreover, the application of BIO-PCR increased
sensitivity of detection from 102 to 105 times over the standard
PCR. If looking for unknown cultivable bacteria more effective
detection seems to be use of microbiological method enabling
detection on bacteriological media single cells in the fragments
of explants or in wash liquids, in which fragmented explants
were shaken.W pracy określono możliwość wykrywania
obecności bakterii najczęściej spotykanych w kulturach
roślinnych in vitro, należących do różnych rodzajów,
przy pomocy technik mikrobiologicznej i molekularnej.
Za najbardziej przydatną do izolacji uznano
pożywkę 523 a także pożywkę zawierającą 1 soli
mineralnych MS stosowaną do inicjacji kultur roślinnych,
z dodatkiem 0,025% albuminy mlecznej. Większą
czułość wykrywania bakterii przy pomocy markerowego
DNA uzyskano przy zastosowaniu techniki
polegającej na preinkubacji badanego materiału na
pożywkach bakteriologicznych, a następnie na izolacji
DNA ze wzrostu (BIO-PCR). Przy porównaniu sposobów
izolacji DNA większą czułość uzyskano stosując
zestaw Genomic Mini (A&A Biotechnology) niż po
zastosowaniu ekstrakcji w temperaturze wrzenia
Morphological and biochemical characterization of Erwinia amylovora-induced hypersensitive cell death in apple leaves
In attached apple leaves, spot-inoculated with Erwinia amylovora, the phenotypic appearance of the hypersensitive response (HR) and the participation of ethylene, reactive oxygen species (ROS) and of vacuolar processing enzyme (VPE) (a plant caspase-1-like protease) were analysed. The HR in both the resistant and susceptible genotypes expressed a similar pattern of distinguishable micro HR lesions that progressed into confined macro HR lesions. The HR symptoms in apple were compared to those in non-host tobacco. The morphology of dead cells (protoplast shrinkage and retraction from cell wall) in apple leaves resembled necrotic programmed cell death (PCD). Lesion formation in both cv. Free Redstar (resistant) and cv. Idared (highly susceptible) was preceded by ROS accumulation and elevation of ethylene levels. Treatment of infected leaves with an inhibitor of ethylene synthesis led to a decrease of ethylene emission and suppression of lesion development in both cultivars. In the resistant but not in the susceptible apple cultivar an early and late increase in VPE gene expression was detected. This suggests that VPE might be an underlying component of the response to E. amylovora in resistant apple cultivars. The findings show that in the studied pathosystem the cell death during the HR proceeds through a signal transduction cascade in which ROS, ethylene and VPE pathways play a role
Effects of silvicultural techniques on the diversity of microorganisms in forest soil and their possible participation in biological control of Armillaria and Heterobasidion
Effects of different pre-planting soil preparations and post-harvest wood debris applications in a clear-cut Scots pine plantation,
on the abundance, diversity, and activity of culturable microorganisms were investigated. The investigation was done 9 years
after the re-plantings had been done. This formed part of an investigation of silvicultural practices for conservation and the biological
control of Armillaria and Heterobasidion in northern temperate forests (Poland). The treatments being compared, were expected to
have altered the soil’s physical and chemical properties, and consequently, its biological properties. Only soft-rot microfungi from
the Ascomycota and Zygomycota were detected in the soil. Fungi, including those antagonistic to Armillaria and Heterobasidion, were
more abundant after shallow ploughing than after deep ploughing or ridging, and where chipped rather than coarse wood debris was
left on the soil surface or incorporated. Scots pine trees had the most biomass and the least mortality after ridging and leaving coarse
wood debris on the surface (associated with only a relatively moderate abundance of fungi)