The symbiosis of Bacillus subtilis L-forms with Chinese cabbage seedlings inhibit conidial germination of Botrytis cinerea

Aims: To establish whether germination of Botrytis cinerea was affected by the symbiosis of Bacillus subtilis L-form bacteria with Chinese cabbage.

Methods and Results: Germinating seeds of Chinese cabbage were co-cultivated with either L-forms of Bacillus subtilis or 59,6 (w/v) mannitol by soaking for 3 h. Seeds were then washed in sterile water, sown on a minimal medium and incubated in controlled conditions. L-form symbiosis was detected over a time course by ELISA. Conidial germination of Botrytis cinerea was significantly reduced on cotyledonous leaves of L-form-treated plants compared with controls.

Conclusions: Symbiosis of B. subtilis L-form bacteria during seed germination of Chinese cabbage inhibits conidial germination in plants on subsequent exposure to Botrylis cinerea.

Significance and Impact of the Study: This is the first account of plant symbiosis with L-form, bacteria showing antagonism to a fungal plant pathogen. This has promising implications for the use of this L-form as a biocontrol agent.