Conclusion: An ELISA that selectively detects B. subtilis L-form bacteria was developed
and shown to con®rm the presence of L-forms in plants.
Signi®cance and Impact of the Study: This will be a valuable rapid method to further
studies on L-form plant interactions.
INTRODUCTION
L-form bacteria, i.e. those with modi®ed or no cell walls
(Madoff 1986), have been shown to form associations with
plants (Aloysius and Paton 1984). Initial reports on this
novel symbiosis relied on direct observation of the bacteria
in plant tissues, con®rmed using optical brighteners and
immuno¯uorescence techniques (Jones and Paton 1973;
Paton and Innes 1991). Agglutination tests have been used
successfully, alongside corroborative immuno¯uorescence
staining, for the rapid screening and selection of L-formassociated
glasshouse-grown plants (Amijee et al. 1992).
Although molecular techniques have been used to demonstrate
the L-form plant symbiosis (Waterhouse et al. 1994)
such assays do not, by themselves, distinguish between the
different morphological forms and tend to be more time
consuming than many immunological assays. Pseudomonas
syringae pv. phaseolicola L-form bacteria have been shown
to persist, without any effect, throughout the growth and
development of bean plants (Amijee et al. 1992) with the
L-form bacteria being intracellular (Paton and Innes 1991).
Moreover, L-form-inoculated plants have also been shown
to be protected from subsequent challenge by some pathogens
(Amijee et al. 1992; Waterhouse et