Download Brown garden snail: Their microbial associates a proposal to use

E. P. Caswell-Chen and K. R. Sanchez. Brown garden snail: Their microbial
associates and a proposal to use them as biosentinels to detect pathogens.
Department of Entomology and Nematology and Department of Plant Pathology,
University of California, Davis, CA 95616, USA.
Helix aspersa, the Brown Garden Snail, is a common terrestrial mollusk in California.
It is native to the Mediterranean and was introduced to Santa Rosa, California in the
1850’s as a food source, escargot. It is an invasive pest and causes damage to plants
in gardens, vegetable crops, ornamental plantings, orchards, and nurseries. Here, we
describe the nematodes, bacteria, and fungi associated with Helix aspersa from nine
different sites in California. A total of 550 snails were collected. Individual snails
were dissected, and nematodes, bacteria, and fungal isolates were recovered. A
range of nematode operational taxonomic units (OTUs) were recovered from the
snails, ranging from bacterial feeders, such as Ceanorhabitis elegans and
Panagrolaimus sp., to plant-parasitic nematodes such as Ditylenchus dipsaci,
Pratylenchus sp., and Aphelenchoides fragariae. The bacteria isolated included E. coli
and Psuedomonas putida, and fungi such as Fusarium solani, F. oxysporum f. sp.
chrysanthemi, and Rhizoctonia solani. The temperature and moisture preferences of
the snails and slugs, combined with their foraging preferences, clearly lead to
associations with plant parasites. Because mollusks are mobile and traverse soil
and plant material, they are, in effect, sampling the environment. Our observations
establish the diversity of microbes associated with H. aspersa, and we have
established its potential role as an important phoretic host or vector for plant
pathogens. Given the range of nematodes, bacteria, and fungi we have observed
associated with the BGS, we suggest that snails and slugs can be used as biosentinels
or biomonitors to aid in sampling to detect plant pathogens as part of an IPM
program - providing for enhanced sampling and possible rapid and early detection
of pathogens.