Spatial distribution of fungal endophyte genotypes in a Woollsia pungens (Ericaceae) root system

Abstract

Fungal endophytes were isolated from hair roots of Woollsia pungens Cav. (Muell.) and mapped according to the root portions from which they were isolated. A total of 119 isolates was obtained and restriction fragment length polymorphism (RFLP) analysis of the internal transcribed spacer (ITS) region indicated that the isolate assemblage comprised five RFLP types. ITS sequence comparison revealed that RFLP Types I and II had 99.6–99.8% sequence identity with known ericoid mycorrhizal endophytes from Australian epacrids. The remaining three RFLP types were most similar to non-mycorrhizal ascomycetes. Eighty-five per cent of isolates obtained were of RFLP Type I and these were widespread within the root system. Inter-simple sequence repeat PCR suggested that 94% of RFLP Type I isolates were of a single genotype that was widely distributed within the root system, with the remaining five isolates each representing a different genotype. Apparent spatial dominance of the root system by a single fungal genotype may indicate limited functional diversity in the mycorrhizal endophyte assemblage.