Amphibian chytridiomycosis caused by Batrachochytrium dendrobatidis has spread at an alarming rate over large distances throughout sensitive frog populations in eastern Australia, Central America and New Zealand. Infected amphibians and contaminated water are implicated in translocation, but other vectors are unknown. Through in vitro studies we show that potential means of translocation may be moist soil and bird feathers. B. dendrobatidis survived for up to 3 mo in sterile, moist river sand with no other nutrients added. B. dendrobatidis attached to and grew on sterile feathers and were able to be transported by feathers to establish new cultures in media, surviving between 1 and 3 h of drying between transfers. If these in vitro results are valid in the natural environment, the findings raise the possibilities that B. dendrobatidis may be translocated by movement of moist river sand and that birds may carry the amphibian chytrid between frog habitats. However, further studies using sand and feathers containing normal microflora are essential.

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Possible modes of dissemination of the amphibian chytrid Batrachochytrium dendrobatidis in the environment

Molecular recognition in the homing responses of zoosporic fungi, with special reference to Pythium and Phytophthora

Advances in research on oomycete root pathogens

(1993). Looking at Mycology with a Janus Face: A Glimpse at Chytridiomycetes Active in the Environment. Mycologia: Vol. 85, No. 1, pp. 1-20.

Looking at mycology with a Janus face: a glimpse at chytridiomycetes active in the environment

Chytridiomycota, often referred to as chytrids, can be virulent parasites with the potential to inflict mass mortalities on hosts, causing e.g. changes in phytoplankton size distributions and succession, and the delay or suppression of bloom events. Molecular environmental surveys have revealed an unexpectedly large diversity of chytrids across a wide range of aquatic ecosystems worldwide. As a result, scientific interest towards fungal parasites of phytoplankton has been gaining momentum in the past few years. Yet, we still know little about the ecology of chytrids, their life cycles, phylogeny, host specificity and range. Information on the contribution of chytrids to trophic interactions, as well as co-evolutionary feedbacks of fungal parasitism on host populations is also limited. This paper synthesizes ideas stressing the multifaceted biological relevance of phytoplankton chytridiomycosis, resulting from discussions among an international team of chytrid researchers. It presents our view on the most pressing research needs for promoting the integration of chytrid fungi into aquatic ecology.

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Integrating chytrid fungal parasites into plankton ecology: research gaps and needs

In laboratory experiments, zoospores of Rhizophlyctis rosea accumulated and encysted on cellulose (transparent film, lens tissue and filter paper) but not on chitin (crab shell) ‘baits’. Zoospores of Chytridium confervae, Pythium aphanidermatum and a Saprolegnia sp. accumulated on chitin but not on cellulose. Zoospores of Allomyces arbuscula, Pythium graminicola and other fungi accumulated on both cellulose and chitin, whereas spores of some fungi, e.g. P. oligandrum , did not accumulate on cellulose or chitin. Initial contact of zoospores with these materials occurred at random, not by taxis, but was followed by characteristic behavioural changes of the zoospores. Zoospore accumulation could be reduced or prevented by prior treatment of cellulose or chitin with dyes or a lectin, suggesting that surface recognition events mediate zoospore accumulation.

R.T. Mitchell

Papers

Selective accumulation of zoospores of chytridiomycetes and oomycetes on cellulose and chitin