An Aqueous Extract of the Dry Mycelium of Penicillium chrysogenum Induces Resistance in Several Crops under Controlled and Field Conditions

Abstract

We have examined the effect of Pen, an aqueous extract of the dry mycelium of Penicillium chrysogenum, on plant-pathogen interactions. Pen controlled a broad range of pathogens on several crop plants under greenhouse and field conditions. Pen protected grapevine from downy and powdery mildew (caused by Plasmopara viticola and Uncinula necator), tomato from early blight (caused by Phytophthora infestans), onion from downy mildew (Peronospora destructor) and apple trees from apple scab (caused by Venturia inaequalis) to a similar extent as fungicides such as copper and sulphur or well-known inducers such as benzothiadiazole or b-aminobutyric acid. Pen had no major direct fungicidal effect and is thus supposed to protect plants by activating their defense mechanisms. The raw material for extraction of Pen was available in constant quality, a prerequisite for commercial application. Under certain conditions, Pen caused phytotoxic side effects. The symptoms mostly consisted of small necrotic spots or, more rarely, of larger necrotic areas. The development of the symptoms was dependent on several parameters, including concentration of Pen, the number of applications, the persistence on the plant tissue, the plant species and variety and environmental conditions. In grapevine, a partially purified fraction of Pen was much less toxic than the crude Pen extract, but protected the plants to a similar extent against P. viticola. Our data show that Pen has interesting and unique properties as a plant protection agent, but more research is needed to further reduce its phytotoxic side effects.

High efficacy of extracts of Cameroon plants against tomato late blight disease

“…The positive effect obtained with C. benthamii and E. floribundus extracts could be the result of induced resistance and the induction of tomato plants to produce disease-fighting compounds. Similar mechanisms of action were reported in tomato using pen, an aqueous extract of the dry mycelium of Penicillium chrysogenum (Thuerig et al, 2006), indole-3-acetic acid, ethephon and fusicoccin (Christ and Mösinger, 1989), and in potato using unsaturated fatty acids in potato (Cohen et al, 1991). Disease suppression on detached leaflets was generally associated with disease suppression on whole tomato plants and negatively correlated with disease latency.…”

Effects of fertilizers and plant strengtheners on the susceptibility of tomatoes to single and mixed isolates of Phytophthora infestans

“…However, foliar application of PEN has also resulted in phytotoxicity especially on grapes (Thuerig et al 2006). When applied to the soil as was done in the experiments reported here, no such effects were observed on tomatoes.…”

“…A variety of defence mechanisms are activated in tomato plants induced by BABA, including physical barriers and biochemical changes leading to resistance against P. infestans (Cohen 2002). PEN has been shown to induce early defence reactions against P. infestans in tomatoes including accumulation of ethylene, hydrogen peroxide and peroxidase (Thuerig et al 2006;Unger et al 2006). The seaweed extract in the plant strengthener QUALITY might have hormonal activities like auxin and gibberellin, which induced resistance in tomatoes.…”

“…The nutrient content of QUALITY is 0.02% N, 0.004% P and 0.09% K (Analysis by Institut für Düngemittel und Saatgut (LUFA) in Hameln, Germany). PEN is known to induce resistance against late blight in tomatoes (Thuerig et al 2006;Unger et al 2006). It was prepared from dry mycelium of Penicillium chrysogenum (which is sold as the organic fertilizer Biosol) according to Dong and Cohen (2002): 100 g of dry mycelium was suspended in 1 l of distilled water.…”

“…In addition to some well-known chemical inducers such as BABA (DL-3-amino-butyric acid), several plant extracts and fungus-derived compounds, suitable for organic farming, have been identified, with the ability to reduce the susceptibility of tomatoes to P. infestans through IR (e.g., Stephan et al 2005;Thuerig et al 2006;Unger et al 2006;Portz et al 2008).…”