Allyl Isothiocyanate in the Volatiles of Brassica juncea Inhibits the Growth of Root Rot Pathogens of Panax notoginseng by Inducing the Accumulation of ROS

The cultivation of Panax notoginseng is often seriously hindered by
root rot disease caused by the accumulation
of soil-borne pathogens. Here, the inhibitory activity of Brassica juncea volatiles on P. notoginseng root rot pathogens was assessed and compounds in volatiles were
identified. Furthermore, the antimicrobial activity and mechanism
of allyl isothiocyanate (AITC) were deciphered by integrated transcriptome
and metabolome analyses. The volatiles of B. juncea showed dose-dependent antimicrobial activity against root rot pathogens.
AITC, identified as the main volatile compound, not only significantly
inhibited pathogen growth in vitro but also suppressed
root rot disease in the field. Integrated transcriptomic and metabolomics
analysis revealed that AITC inhibited Fusarium solani by interfering with energy production and induced the accumulation
of ROS by decreasing the content of glutathione (GSH). In summary, B. juncea releases AITC to inhibit soil-borne pathogens
and could be used as a rotation crop or soil fumigant to alleviate
root rot disease.