Dimethyl disulfide is an induced systemic resistance elicitor produced by Bacillus cereus C1L.

Bacillus cereus C1L is a plant growth-promoting rhizobacterium and can elicit induced systemic resistance (ISR) in plants against necrotrophic pathogens. However, little is known about ISR elicitors produced by B. cereus C1L, and no ISR elicitor has been identified and characterised. Therefore, the objective of this study is to identify volatile ISR elicitor(s) produced by B. cereus C1L. The volatile metabolites produced by B. cereus C1L were extracted, separated and identified by solid-phase microextraction, gas chromatography and mass spectrometry. Dimethyl disulfide (DMDS) was the only separated metabolite being determined. Afterwards, application of DMDS by means of soil drench significantly protected tobacco and corn plants against Botrytis cinerea and Cochliobolus heterostrophus, respectively, under greenhouse conditions. The results reveal that DMDS could play an important role in ISR by B. cereus C1L. This is the first report of DMDS as an elicitor produced by an ISR-eliciting B. cereus strain and its ability to suppress plant fungal diseases under greenhouse conditions. It is suggested that DMDS has potential for practical use in controlling plant foliar diseases besides soil fumigation.