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Ascochyta blight (Ascochyta rabiei) is one of the most devastating diseases of chickpea. The biocontrol potential of fungal antagonists, Chaetomium globosum, Trichoderma viride, Acremonium implicatum were explored under in vitro and in vivo. A. implicatum isolate-1 overgrew the host mycelium and caused lysis, while A. implicatum isolate-2 produced inhibition zone. C. globosum profusely overgrew the mycelium of A. rabiei and T. viride showed overgrowth and profuse sporulation. Bioassay with culture filtrates of all the antagonists resulted in significant inhibition of pycnidiospore germination and reduction in colony development of A. rabiei. Syringe filtered culture filtrate when amended in liquid broth medium also significantly reduced the mycelial growth. Bioassay of culture filtrates under glass house conditions, although brought reduction in disease development in both pre- and post-inoculation sprays, but C. globosum was the most effective antagonist causing 73.12% reduction in disease index when used as post inoculation spray. Under in vitro conditions C. globosum caused 48.59% reduction in colony diameter and 70.86% reduction in pycnidiospore germination.
Siderophores are low molecular weight (<1000 D) iron chelating compounds produced by microorganisms. Production of siderophore is a device of antagonism as by virtue of the capacity of siderophore production, a microorganism competes for Fe (III) with the others. Production of siderophores by 9 different soil fungi and wood-decay fungi was studied following CAS - assay and CAS - agar plate assay. Optimization for the production of siderophores was done by varying the levels of pH and Fe (III) concentrations in the low nutrient medium. All the test fungi could produce siderophores, though the degree of production recorded to be very low both in Botryodiplodia theobromae and in Fusarium spp. On the other hand, all the species of Trichoderma showed their excellency in siderophore production. The optimum pH for production of siderophores remained at neutral pH level though the range varied from pH 6.0-8.0. The optimum range of the concentration of Fe (III) required for siderophore production was recorded to be 1.5-21.0 µM. However, the stress condition of iron might be a decisive factor for siderophore production.
Fekete, C., Weszely, T., Hornok, L. (1996): Assignment of a PCR-amplified chitinase sequence cloned from Trichoderma hamatum to resolved chromosomes of potential biocontrol species of Trichoderma . FEMS Microbiol. Lett. 145 , 385
157 131 135 Naár Z. and Bíró B. 2006. Species composition of indigenous Trichoderma fungi affected by Cd, Ni and Zn heavy metals in calcareous
Mycoviruses are known to infect fungi of different habitats and life style. Some of them, like the Mushroom Virus X (MVX) complex, cause abnormal development of fruiting bodies and severe yield losses in mushroom cultivation. Most mycoviruses have a double-stranded RNA (dsRNA) genome, therefore dsRNA-detection is frequently used as a first step to identify virus infection. In relation with MVX 23 dsRNAs species have been described, occurring in variable number and combination in diseased mushrooms. The aim of our experiments was to find out whether dsRNA-immunoblotting can be used to detect dsRNA in small samples of cultivated A. bisporus varieties and of wild growing Agaricus species. We found that by immunoblotting, the same dsRNA species were detected in apparently healthy cultivated champignon fruiting bodies and in MVX-infected reference samples, respectively, as by conventional CF11 chromatography, but for immunoblotting a much smaller sample size was needed. In two out of three deformed fruit bodies of cultivated A. bisporus from Hungary we detected a 4.1 kbp dsRNA species which was also present in the MVX infected reference samples. Diverse and variable dsRNA patterns were observed in apparently healthy samples of 12 wild growing Agaricus species, indicating that extreme care should be taken when non-cultivated Agaricus is used for breeding new varieties. Non-sterile cultures and environmental mushroom specimens are fairly often mixed with parasitic and endofungal organisms, therefore, we also tested fungi isolated from mushroom cultures. Here again, 1–7 dsRNA species were found in extracts of Trichoderma and Dactylium isolates and of Mycogone-infected sporophores. Our results demonstrate clearly that dsRNAs from very different origins can be present in cultivated champignon and support the view that the MVX symptom-associated dsRNAs are probably of polyphyletic origin and do not represent one defined virus.
. Z. Naár B. Biró 2006 Species composition of indigenous Trichoderma fungi affected by Cd, Ni and Zn heavy metals in calcareous chernozem soil
role of soil microbiota during colonization of different soil types by Trichoderma fungi. Acta Microbiol. Immunol. Hung. 46 . 212--213. The role of soil microbiota during colonization of different soil types by
A talajok eredményes szennyvíziszap-kezelése érdekében szükséges vizsgálni a talaj biológiai tulajdonságait, melyek szoros összefüggésben vannak a talaj minőségével. A talajok biokomponensei általában gyorsabban reagálnak a változó talajkörülményekre, mint a talaj fiziko–kémiai tulajdonságai, ezért a talajban élő mikrobapopulációk és az enzimaktivitás mértéke bioindikátorként szolgál a talaj termőképességét illetően. Kísérletünkben vizsgáltuk a nyíregyházi és hódmezővásárhelyi eredetű kommunális szennyvíziszappal (100:0, 20:80, 40:60, 60:40, 0:100%, talaj:iszap) kezelt réti csernozjom talaj, kovárványos barna erdőtalaj és agyagbemosódásos barna erdőtalaj – kontrolhoz viszonyított – fizikai, kémiai és biológiai tulajdonságait, valamint összemértük a kezelt és kezeletlen (kontroll) talajok termőképességét a paradicsomnövény példáján 63 napos termesztést követően. Eredményeink azt mutatják, hogy a szennyvíziszap-kezelés növelte a talaj pH(KCl)-értékét, szervesanyag-tartalmát, CO 2 -termelését (talajlégzést) és nedvességtartó idejét is meghosszabbította. A terméshozamot illetően a kezelt talajoké minden esetben felülmúlták a kontrolltalajokét. A legmagasabb terméshozamot a 60% nyíregyházi eredetű szennyvíziszappal kezelt kovárványos barna erdőtalaj esetében (1,5–2-szeres) kaptuk. A kezelt talajok esetében ugyancsak szignifikáns növekedés volt tapasztalható a heterotróf bakériumok, aerob heterotróf spórások, cellulózbontók és foszfátoldók, Bacillus , fluorescens Pseudomonas -ok, aktinomicéták, fonalas gombák, valamint élesztőket illetően. Ennek köszönhetően nőtt a kezelt talajok FDA, dehidrogenáz, kataláz, ureáz, proteáz, foszfatáz, β-glükozidáz, invertáz és aril-szulfatáz aktivitása is. Jelen enzimek aktivitása lineárisan emelkedő korrelációt mutat a talaj szervesanyag-tartalmával, mely a talajokhoz adagolt szennyvíziszapnak köszönhető. Összefoglalásképpen, a talajok szennyvíziszappal való kezelése serkenti a növényi növekedést, javítja a rizoszféra fizikai, biokémiai és mikrobiális tulajdonságait, segít megőrizni a talaj nedvességtartalmát, valamint emeli a talaj pH-értékét, amely ugyancsak kedvező a növények növekedése szempontjából.
, N. J., Daginawala, H. F., Chakakrabarti, T., Khanna, P. (1995) Enhanced cellulase production by mutant of Trichoderma reesei . Enzyme Microb. Technol. 17, 942–946. Khanna P
oat hulls by Aspergillus ferulic acid esterase and Trichoderma xylanase. J. Agric. Food Chem. 50 :1625–1630. Christensen D.A. Release of ferulic acid from oat hulls by
