Tolerance and biodegradation of m-toluate by Scots pine, a mycorrhizal fungus and fluorescent pseudomonads individually and under associative conditions
I. Sarand et al., Tolerance and biodegradation of m-toluate by Scots pine, a mycorrhizal fungus and fluorescent pseudomonads individually and under associative conditions, J APPL MICR, 86(5), 1999, pp. 817-826
The tolerance to, and degradation of m-toluate by Scots pine (Pinus sylvest
ris), a symbiotic mycorrhizal fungus (Suillus bovinus) and Pseudomonas fluo
rescens strains, with or without m-toluate-degrading capacity, was determin
ed individually and in all symbiotic/associative plant-microbe combinations
. Fungal survival on medium with m-toluate was increased in co-culture with
the degradative bacterial strains on agar plates (up to 0.02%, w/v). When
fungi were grown in mycorrhizal association with Scots pine seedlings in te
st-tube microcosms containing expanded clay pellets and growth media, the f
ungus was able to withstand m-toluate concentrations up to 2.0%, w/v in all
treatments. The seedling tolerance remained unaltered regardless of the pr
esence or absence of mycorrhizal fungi or biodegradative bacteria. Reductio
n in m-toluate levels was only detected in treatments inoculated with bacte
rial strains harbouring TOL catabolic plasmids. The plant and fungus, alone
or in mycorrhizal symbiosis, were unable to cleave m-toluate. The presence
of easily available plant-derived carbon sources did not impede m-toluate
degradation by the bacteria in the mycorrhizosphere.