Response of rhizosphere microbial communities associated with Antarctic hairgrass (Deschampsia antarctica) to UV radiation

The response of rhizosphere microbial communities associated with natural populations of Deschampsia antarctica growing on Leonie Island (67degrees36'S, 68degrees21'W, Antarctic Peninsula) to UV radiation was investigated. UV radiation was controlled in the field using Perspex VA screens (UV-B opaque) which transmit little radiation below 380 nm but allow penetration of approximately 92% of radiation above 400 nm, and Perspex OXO2 screens (UV-B transparent) which transmit approximately 70% of radiation at 280 nm, rising to 90% at 300 nm and above. Reducing ambient UV radiation altered the phenotypic profile of the rhizosphere microbial community. This alteration was expressed as enhanced carbohydrate and carboxylic acid utilisation by the rhizosphere micro-organisms. It is hypothesised that ambient levels of UV radiation indirectly affect rhizosphere micro-organisms by influencing the quality or quantity of root exudates.