Some Chytridiomycota in soil recover from drying and high temperatures

Rhizophlyctis rosea was found in 44% of 59 soil samples from national parks, urban reserves and gardens, and agricultural lands of eastern New South Wales, Australia. As some of the soils are periodically dry and hot, we examined possible mechanisms that enable survival in stressful environments such as agricultural lands. Air-dried thalli of R. rosea in soil and pure cultures of R. rosea, two isolates of Allomyces anomalus, one isolate of Catenaria sp., one of Catenophlyctis sp. and one of Spizellomyces sp. recovered following incubation at 90 degrees C for two days. Powellomyces sp. recovered following incubation at 80 degrees. Sporangia of all seven fungi shrank during air-drying, and immediately returned to turgidity when rehydrated. Some sporangia of R. rosea released zoospores immediately upon rehydration. These data indicate that some Chytridiomycota have resistant structures that enable survival through periodic drying and high summer temperatures typical of soils used for cropping. Eleven Chytridiomycota isolated from soil did not survive either drying or heat. Neither habitat of the fungus nor morphological type correlated with the capacity to tolerate drying and heat.