Virulence of Oomycete Pathogens from \u3cem\u3ePhragmites australis\u3c/em\u3e-Invaded and Noninvaded Soils to Seedlings of Wetland Plant Species

Soil pathogens affect plant community structure and function through negative plant-soil feedbacks that may contribute to the invasiveness of non-native plant species. Our understanding of these pathogen-induced soil feedbacks has relied largely on observations of the collective impact of the soil biota on plant populations, with few observations of accompanying changes in populations of specific soil pathogens and their impacts on invasive and noninvasive species. As a result, the roles of specific soil pathogens in plant invasions remain unknown. In this study, we examine the diversity and virulence of soil oomycete pathogens in freshwater wetland soils invaded by non-native Phragmites australis (European common reed) to better understand the potential for soil pathogen communities to impact a range of native and non-native species and influence invasiveness. We isolated oomycetes from four sites over a 2-year period, collecting nearly 500 isolates belonging to 36 different species. These sites were dominated by species of Pythium, many of which decreased seedling survival of a range of native and invasive plants. Despite any clear host specialization, many of the Pythium species were differentially virulent to the native and non-native plant species tested. Isolates from invaded and noninvaded soils were equally virulent to given individual plant species, and no apparent differences in susceptibility were observed between the collective groups of native and non-native plant species

Pasożyty związane z organizmami planktonowymi i peryfitonowymi strefy litoralowej jezior Draweńskiego Parku Narodowego

Studies on parasitism in zooplankton and periphyton assemblages were carried out on samples of water collected from Lakes Płociczno and Płociowe in the Drawa National Park in 2008-2011. Occurrence of the fungal mycobiotal and protozoan parasites of invertebrates was recorded in both lakes. Parasitism of Chydorus sp. (Cladocera) by Saprolegnia sp. occurred on 0.8% of individuals of the host population, of Brachionus calyciflorus (Rotifera) by Microsporidium sp. on 1.2% of the host population, and of Nematoda members by Pythium sp. on 5% of the host population. Parasites were recorded only in springtime.W latach 2008-2011 badano występowanie mikroorganizmów pasożytniczych na gatunkach tworzących zooplankton i peryfiton litoralowy w jeziorach Płociczno i Płociowe w Drawieńskim Parku Narodowym. Występowanie patogenów na organizmach tych zespołów stwierdzono jedynie wiosną. Udokumentowano porażenie Chydorus Leach (Cladocera) przez Saprolegnia sp., Brachionus calyciflorus Pall. (Rotifera) przez Microsporidium sp. oraz przedstawiciela Nematoda przez Pythium sp. Porażenie przez patogeny dotyczyło 0,8% populacji Chydorus sp., 1,2% populacji Brachionus calyciflorus oraz 5% populacji niezidentyfikowanych do gatunku nicieni (Nematoda). W pracy przeanalizowano uzyskane wyniki na tle innych, podobnych badań i przedyskutowano prawdopodobne przyczyny niewielkiego stopnia porażenia organizmów planktonowych i peryfitonowych przez pasożyty. Wskazano także na obserwowaną przez niektórych autorów zależność występowania pasożytów od dynamiki sezonowej występowania ich żywicieli

Antagonistic interactions between saprotrophic fungi and geohelminths. 1. Saprotrophic fungi in the biological control of phytopathogenic geohelminths

The state of knowledge on the possible antagonism between soil saprotrophic fungi and phytopathogenic nematodes of the genera Meloidogyne, Heterodera, and Globodera is reviewed basing on the literature and our own research. Mycelial colonisation of various developmental stages of these geohelminths is the most common factor thought to reduce their populations in nature. The following parasitic fungi can be found on the cysts, eggs, as well as the larvae of the nematodes: Paecilomyces lilacinus, Verticillium chlamydosporium, Cylindrocarpon destructans, Pochonia chlamydosporia, Fusarium spp., and Penicillium spp. The fungi invade the nematodes, such as Heterodera, Globodera, or Meloidogyne, „passively” penetrating through the natural orifices of the cysts, eggs, and larvae of the host. Equally frequent, however, is a biochemical action of the fungi prior to colonisation, which is linked with production of mycotoxins or hydrolytic enzymes. Such an active way of fungal penetration of various stages of the phytopathogenic nematodes has been observed in Pochonia chlamydosporia, Penicillium verrucosum var. cyclopium, P. frequentans, Sclerotinia rolfsii, Rhizoctonia solani, and Fusarium spp. Triacylglycerols (TAG), phenols, as well as trichothecene, T-2, have been found in the metabolites extracted from mycelia of these species. Predation by fungi is also a factor that may reduce a population of phytopathogenic nematodes. This form of antagonism is characteristic for nematicidal fungi of the genera Arthrobotrys and Dactylella. These fungi form shrinking rings and hooks in their mycelia by which the fungus entangles and paralyses a migrating form of nematode. Despite the fact that the antagonism between fungi and nematodes is a commonly occurring phenomenon observed in the soil, the nematicidal and nematotoxic properties of fungi have not a wide application in biological plant protection. Up till now, only the bionematicides based on Arthrobotrys robusta (Royal 300 and Royal 350) as well as Paecilomyces lilacinus (Biocon and PL Plus) have found its commercial application

Z badań grzybów fitopatogenicznych i saprofitycznych w zbiorowiskach szuwarowych Jeziora Glinno

During the vegetation seasons in years 2004-2005 the health state of rush plant species from Phragmitionand Magnocaricionalliances around the Lake Glinno was investigated. From 13 plant species with disease symptoms 94 species of fungi and FLO were isolated. The highest mycological biodiversity was stated in Phragmitetum australis(24 species) and Thelypteridi-Phragmitetum(27 species) plant associations. The host species in which the biggest number of fungi and FLO species was observed were: Phragmites australis(37 species) and Carex acutiformis(25 species). The highest mycological similarity based on the JaccardSörensen coefficient occurred between Caricetum acutiformisand Glycerietum maximae plant associations (50%) whereas the lowest value of the coefficient represented Glycerietum maximaeand Phalaridetum arundinaceaeassociations (7%).W badaniach prowadzonych w latach 2004-2005 stwierdzono występowanie 94 gatunków grzybów i organizmów grzybopodobnych (OGP) na 13 gatunkach roślin, występujących w siedmiu zespołach szuwarowych wokół Jeziora Glinno. Z fragmentów roślin wykazujących objawy chorobowe izolowano zarówno gatunki fitopatogeniczne z rodzajów: Puccinia, Ustilago, Leptosphaeria, Septoria, Fusarium, Pythiumi in. jak i powszechnie obecne saprotrofy rodzajów: Alternaria, Cladosporium, Doratomyces, Periconia, Rotulai in. Największe zróżnicowanie gatunkowe stwierdzono wśród grzybów mitosporowych i Ascomycota, które stanowiły odpowiednio 61,63% i 18,08% wszystkich gatunków. Sporadycznie stwierdzano gatunki Chytidiomycota, Oomycota i Zygomycota. Największa bioróżnorodność mikologiczna charakteryzowała Phragmites australis(37 gatunków grzybów), Carex acutiformis (25 gatunków) i Iris pseudoacorus(19 gatunków)

Species biodiversity of microscopic fungi of common reed [Phragmites australis [Cav.] Trin. ex Steud.] in the rush communities of Lake Glinno

The studies were carried out on common reed (Phragmites australis) growing on the shores of Lake Glinno and forming rush communities of the alliance Phragmition. 10 plants with disease symptoms were gathered from each of five sites. The isolation and marking of pathogens were performed twice from fragments of leaf and blade tissues with disease symptoms. First, directly after collecting the plants incubated in sterile humid chambers and microorganism cultures on CDA and PDA medium, and then phytopathogen and saprotroph species occurring on dried green material were identified for 2-A months. The occurrence of 31 species of microscopic fungi overall was observed on the leaves, blades and inflorescences of P. australis, including 2 mycelia of Mycelia sterilia. The most frequently occurring species, present at all sites of Phragmites australis are: Alternaria alternata, Cladosporium cladosporioides, C. herbarum, Doratomyces stemonitis and Puccinia phragmitis, P. magnussiana and two mycelia of Mycelia sterilia. The most common species occurring on blades and inside them are: Acremoniella atra, Acremonium alternatum and Fusarium sambucinum. Sporadically, Ustilago grandis was also observed inside blades. Tiny necrotic stains on leaves and blades were caused by the presence of three species of the genus Leptoshaeria: L. culmifraga, L. eustoma and L. fuckelli. The occurrence of the sclerote of Claviceps microcephala was found in inflorescences.Badania prowadzono na trzcinie pospolitej (Phragmites australis) porastającej brzegi wokół jeziora Glinno (woj. zachodniopomorskie) i tworzącej zbiorowiska szuwarowe ze związku Phragmition. Z pięciu stanowisk zbierano po 10 roślin z objawami chorobowymi. Izolację i oznaczanie patogenów wykonano dwukrotnie z fragmentów tkanek liści i źdźbeł z symptomami chorobowymi. Najpierw bezpośrednio po zbiorze roślin inkubowanych w sterylnych wilgotnych kamerach i hodowli mikroorganizmów na podłożach CDA i PDA, a następnie przez 2-4 miesiące identyfikowano gatunki fitopatogenów i saprotrofów pojawiające się na ususzonym materiale zielnikowym. Na liściach, źdźbłach i kwiatostanach P. australis stwierdzono łącznie występowanie 31. gatunków grzybów mikroskopowych, w tym dwóch grzybni Agonomycetes (Mycelia sterilia). Najczęściej występującymi gatunkami, obecnymi na wszystkich stanowiskach P. australis są: Alternaria alternata, Cladosporium cladosporioides, C. herbarum, Doratomyces stemonitis oraz Puccinia phragmitis, P. magnussiana i dwie grzybnie Mycelia sterilia. Na źdźbłach oraz w ich wnętrzu najpowszechniej występującymi gatunkami są: Acremoniella atra, Acremonium alternatum i Fusarium sambucinum. Sporadycznie zanotowano także obecność Ustilago grandis we wnętrzu źdźbeł. Drobne nekrotyczne plamistości na liściach i źdźbłach spowodowała obecność trzech gatunków rodzaju Leptoshaeria: L. culmifraga, L. eustoma oraz L. fuckelli. W kwiatostanach stwierdzono obecność sklerocjów Claviceps microcephala

Comparison of the effect of the chosen species of saprotrophic fungi on the development of Toxocara canis and Ascaris suum eggs

The study aim was to compare the antagonistic interaction between saprotrophic soil fungi and embryonic development of geohelminths Toxocara canis and Ascaris suum. The experimental cultures were fertilized eggs of T. canis and A. suum incubated together with mycelium of strains: Fusarium culmorum, Metarhizium anisopliae, Paecilomyces fumosoroseus, Trichoderma viride and Trichothecium roseum. In the control cultures the eggs of both nematode species were incubated without fungi. The experiment was conducted at temp. 26ºC for 60 days. Compared with the control, all of the tested species of fungi significantly extended the embryonic development of both T. canis and A. suum. Most inhibitory effect on the rate of embryonic development of T. canis and A. suum had three fungal species: P. fumosoreus, M. anisopliae and T. viride. Compared with the control, on the 60th day of incubation in the presence of each of the tested fungal species, a larger percentage (p<0.05) of morphological abnormalities was stated in developing embryos of T. canis (49–69%) than in A. suum (15.1–67.7%). Among the examined fungal species, only incubation with P. fumosoroseus resulted in significantly greater (p<0.05) incidence of embryonic malformations (embryopathies) in T. canis, as compared with A. suum. Also the percentage of dead larvae of T. canis in the control and in cultures with fungi (12% and 100%, respectively) was significantly higher in comparison with A. suum (0.5% and 10.3–36%, respectively). The highest percentage of non-viable larvae of A. suum was found in the presence of P. fumosoroseus, and the lowest in the presence of M. anisopliae. Findings may indicate that T. canis eggs are more sensitive to antagonistic interaction of the examined fungal strains than A. suum eggs

Badania toksyczności wybranych Oomycetes

The MTT test is used to determine the cytotoxicity of species: Achlya americana, A. caroliniana, Leptomitus lacteus, Saprolegnia ferax and S. lapponica, which occurred in Lake Sitno in the Drawieński National Park (W P W P oland). It was stated that among five examined species of zoosporic fungi only one of them A. caroliniana, does not show cytotoxic effect. Low and mean toxicity of other tested water FLO, however, combined with the large-scale character of their appearance shows, that they can create serious threat for the spawn, fry, fish as well as the other organisms (including invertebrates) existing in water.Test MTT zastosowanao do badań cytotoksyczności szczepów: Achlya americana, A. caroliniana, Leptomitus lacteus, Saprolegnia ferax i S. lapponica pozyskanych z Jeziora Sitno w Drawieńskim Parku Narodowym. Stwierdzono, że spośród pięciu wymienionych grzybów zoosporowych tylko A. caroliniana nie wykazuje działania cytotoksycznego. Udowodniona niska i średnia toksyczność pozostałych gatunków OGP , w zestawieniu z ich masowym występowaniem w środowisku wodnym, wskazuje, że mogą one stanowić istotne zagrożenie dla ikry, narybku i ryb oraz innych organizmów, w tym także bezkręgowców, żyjących w wodzie