In vitro culture conditions of colletotrichum gloeosporioides: b) Effect of temperature shock on spore production

Hypericum perfuratum is an important plant species used for the production of hypericin, a metabolite of major application in the pharmaceutical industry. Its production is, however, strongly limited by Colletotrichum gloeosporioides, the causative agent of anthracnose. As H. perforatum tolerance to C. gloeosporioides is dependent on plant variety, we intend to select tolerant varieties under in vitro conditions for metabolite production without fungicide application. Selective pressure on plants is induced by inoculation with the fungus spores, but spores are difficult to obtain. The establishment of in vitro conditions for spore production was the main goal of the trials here presented. The influence of changing temperature on spore production of C. gloeosporioides was tested. Four different temperature conditions were tested, using the environment temperature as reference. We tested the influence of an initial cold and heat shock, as well as a cold and heat shock after growth under environment conditions. Preliminary results showed that an initial heat shock induces spore production in C. gloeosporioides. Complementary trials on spore production and in vitro plant inoculation are being developed