Aims: To develop an ELISA for the detection of antigens derived from stable Bacillus
subtilis L-form bacteria and to detect these in plants injected with L-form bacteria.
Methods and Results: A sandwich ELISA was developed and its speci®city was investigated
using L-forms and cell-walled forms of B. subtilis, different Bacillus species and a range of
bacteria isolated from glasshouse-grown strawberry plants. The detection limits of the
ELISA were approximately 103 viable cells ml
ÿ1 for L-forms compared with 107 viable cells
ml
ÿ1 for cell-walled forms. Results showed that L-forms survived and moved within
strawberry tissues injected with L-form bacteria.
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.