Despite their bad reputation, fungi play an important role in the industrial synthesis of many products in everyday use, such as paper and textiles, as well as in the production of biofuels. Researchers at the AIT Austrian Institute of Technology have discovered how the filamentous fungus Trichoderma reesei communicates with members of the same species upon reproduction. These new findings will bring about further advances in enhancing this fungus.7.5.2015
Trichoderma reesei is one of the most important biotechnological workhorses worldwide and is exploited in biotechnology for production of a wide variety of enzymes and performance proteins. These proteins are used in the pulp and paper industry, for textile processing and most importantly for production of second generation biofuels. Trichoderma reesei is easy to cultivate and has a long history of research and strain improvement, making it particularly attractive to industry.
Trichoderma reesei, a filamentous fungus was the first commercially important mold for which a technique for sexual crossing under laboratory conditions was developed. Hence it is now possible to improve and further develop the characteristics of the strain through selective breeding, as has long been common practice with plants. In the past, improvements in Trichoderma reesei could only be achieved by genetic engineering or using random mutagenesis with chemicals.
However there are still a number of fungi in industrial use for which crossing is a very slow process, or of unreliable outcome or it does not work at all. There are also many fungi used in biological pest control for which sexual crossing has not yet been achived. The ability to breed these particular fungi without application of genetic engineering would be a crucial advantage for improving their adaptation to soil and climatic conditions as well as their performance. Understanding the processes taking place in Trichoderma reesei also offers novel perspectives for improvements of crossing with other fungi or to achieve their crossing in the first place.
Enhancing applications of fungi
For the first time, scientists have succeeded in demonstrating the “chemical” communication between potential partners of Trichoderma reesei. It was not known until now that fungi respond to potential partners not only with peptide pheromones but also with such specific chemical signals. “Our results have revealed more about the sexual development of fungi and about the chemical signals which are transmitted in this process. By investigating communication between mating partners in depth, we are able to provide strategies to enhance the fungus for commercial exploitation. Our research into these signals in Trichoderma is taking us into uncharted territory”, explains Monika Schmoll, Senior Scientist at the AIT’s Health & Environment Department. The experts have published their results in the respected Journal “Molecular Microbiology”.
Exploiting natural resources and production methods as well as biological methods of strengthening plant resistance and pest control are key research areas at AIT.
Communication via pheromone signals
In the recent study researchers from AIT and the University of Natural Resources and Life Sciences (BOKU, Division of Chemistry of Renewable Resources) tried to gain a better understanding of the processes involved in sexual development and to optimise the crossing of different strains and thereby the combination of different characteristics. Thereby, they discovered that a protein of the VELVET family is important for pheromone- and chemical communication between two T. reesei strains and their successful sexual reproduction. It regulates the sending and receiving of pheromone signals as well as the secretion of tiny molecules as soon as a potential mating partner is detected in the vicinity.
Further research into signalling pathways
In the next stage the experts are keen to examine which genes influence communication between two fungi prior to mating and which further signalling pathways are involved in this communication. “If we investigate this communication further, this might help to enable sexual development in other species, where this has not yet been possible”, explains Schmoll.
Molecular Microbiology. “Mating type-dependent partner sensing as mediated by VEL1 in Trichoderma reesei”. Bazafkan Hoda, Dattenböck Christoph, Böhmdorfer Stefan, Tisch Doris, Stappler Eva, Schmoll Monika. 2015 Mar 11. doi: 10.1111/mmi.12993. [Epub ahead of print]