Posted on 19/03/2010
Professor Alan Gange
Professor Alan Gange, from the School of Biological Sciences at Royal Holloway, University of London, provided an insight into the fascinating world beneath our feet in his inaugural lecture looking at how soil microbes affect life above ground.
Communities of organisms are linked together in food webs. Until recently, it was assumed that the soil food web existed more or less in isolation from the organisms in the above ground web. Using examples from different biological scenarios, Professor Gange explained how soil microbes are fundamental to the functioning of above ground communities and can affect things as diverse as the size of a caterpillar, the quality of the food you eat, or your round of golf.
Through his research, Professor Gange found that a fungus, called an arbuscular mycorrhiza, which grows in plant root systems, can change the biochemical and architectural features of plants which in turn affects the insects that feed on the leaves or visit the flowers.
“The fungus is very good at absorbing phosphate from the soil. Phosphate is extremely useful in helping a plant to grow at the seeding stage and important in helping it to flower and fruit, but most plants are very limited in their ability to absorb it from the soil. The fungus takes up phosphate and donates it to the plant. In return, it receives a supply of carbon from the host plant”, he said.
To establish the consequences of these changes for insects Professor Gange said he and his colleagues conducted various experiments, one of which focused on the Garden Tiger Moth. The results showed the insects were smaller when they fed from the plants where the fungus was present.
In a similar experiment using Vine Weevils and strawberry plants, the results revealed that not only were the insects smaller but the strawberries on those plants were sweeter, suggesting the fungi affects the quality of the fruit as well.
According to Professor Gange, “If we can identify the resistance features concerned then we may be able to manipulate plants so that they are resistant to pest insects.” This would open up an entirely new area of biological control and greatly reduce our reliance on chemical pesticides.
Professor Gange told the lecture hall about how his father, Ted Gange had collected more than 64,000 records of fungi fruiting in the New Forest over the last 60 years. Through analysing the records, it was evident that fungi are incredibly responsive to changes in our climate. This, said Professor Gange, has implications on the effects of the mycorrhizal fungus because as our weather gets warmer the fungi is fruiting at different times of the year – meaning the fungus is likely to encounter insects it would not have done before.
To view the lecture in full visit: http://mediasite.rhul.ac.uk/rhul/Viewer/?peid=bc4c10c44e3342e1882e8c7f57a743b2