poster ECFGversie2 gecorrigeerd.pub
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poster ECFGversie2 gecorrigeerd.pub
Identification of micro-organisms fighting T. agrresivum and other “Weed” fungi in mushroom compost N. Jacobs(1), M. van Erp(1), W. Arts(2), T. Goosen, C.A.M.J.J. van den Hondel (3)and B. C. Lokman(1) (1) (2) (3) HAN BioCentre: P.O. Box 6960, 6503 GL Nijmegen, the Netherlands, christien.lokman@han.nl CNC: P.O. Box 13, 6590 AA Gennep, the Netherlands HiTeXacoat, Waterlelie 124, 2804 PZ Gouda Introduction The cultivation of mushrooms is susceptible to unwanted growth of fungi, like Trichoderma aggresivum and Penicillium. The growth of these fungi causes substantial decrease of yields to the growers or even destroy the harvest completely. In this study we have identified micro-organisms present in compost that are able to inhibit growth of fungi like T. aggresivum and Penicillium leaving the mycelial growth of the commercial mushroom Agaricus bisporus unaffected. Furthermore, we have shown that Pseudomonas strains derived from natural soil are very effective in inhibiting weed fungi. Methods and Results Method 1: Plate-inhibition assay: 4 different bacterial strains are inoculated at fixed distance from a “weed” fungus on compostmedium agar plate. Growth inhibition was analyzed after 4 days incubation at 28°C (Fig. 1). Used method T. aggresivum (control) T. aggresivum + bacterial strains Penicillium (control) Peniciilium + bacterial strains A. bisporus (control) A. bisporus + bacterial strains X Fig 1. Plate-inhibition assay. X “weed” fungus; o different bacterial strains. Bacteria inhibiting growth of fungus. Method 2: Liquid-inhibition assay: Bacterial strains are cultivated together with different “weed” fungi in liquid compostmedium. Mixed cultures were incubated at 28°C and analyzed on fungal and bacterial growth on compostmedium agar plates (Fig. 2). Mixed cultures in compostmedium Purification method Penicill./37-A2-2 mixculture Penicill./37-A1-5 mixculture Penicill./37-BP-6 + bacterial strains T.aggresivum (control) T.aggr./37-A1-4 mixculture Fig 2. Liquid-inhibition assay. Plates on which T. agresivum and Penicillium are inhibited in growth by bacterial strains are indicated 1 with Final Results inhibition assays: 3 " " " " " " " " " " " " ! " " " " " " " ! " " " " ! " " " " " ! " " " " " ! " " " " "# ! " " 2" " ! " " " " "# Table 1. Final result inhibition assays. Y: Growth inhibition in both assays. Y: Growth inhibition in method 1. N: No growth inhibition in both assays. N: No growth inhibition in method 1. Y/N: Inhibition difficult to determine. Promising strains: growth inhibition of several “weed” fungi leaving A. bisporus unaffected. Conclusion Future plans • • Five bacterial strains present in mushroom compost and three Pseudomonas strains have antifungal activity against T. aggresivum and other “weed” fungi leaving A. bisporus unaffected. • Future research will be focused on the potential of these bacterial strains as biocontrol agents in mushroom cultivation. Highthroughput screening of more strains/compounds on antifungal activity. Acknowledgements This research was financed by the Dutch government (Stichting Innovatie Alliantie: RAAK-Pro), Productschap Tuinbouw, CNC grondstoffen, and HiTeXacoat.