Antimicrobial activities of Brassica campestris L.volatiles to Panax notoginseng(Burk.)F.H.Chen root rot pathogens and chemical component analysis by GC-MS

ObjectiveInhibitory effects of Brassica campestris L. volatiles to major Panax notoginseng root rot pathogens were studied to provide guidance for controlling Panax notoginseng(Burk.)F.H.Chen root rot disease by B. campestris-P. notoginseng rotation or using B. campestris as biological fumigation materials.MethodVolatiles of B. campestris stem and leaves tissues were collected by volatile collection device,and the components and relative contents of volatiles from dissection and grinding tissues were analyzed by gas chromatography-mass spectrometry(GC-MS).Af-ter that,the antifungal activity of volatiles from stems and leaves and sulfoether and isothiocyanate compounds in the voatiles against three root rot pathogens(Fusarium solani F-3,Phytophthora cactorum D-1 and Cylindrocarpon destruc-tans RS006)were determined by hyphal growth rate method.ResultLow concentration of B. campestris stems and leaves promoted the activity of strain F-3,whereas high concentration inhibited its activity.The inhibitory rates against strains D-1 and RS006 were higher than 65.00% with the dosage of 2.0 g/dish.The main components of B.campestris dis-section tissue volatiles was dimethyl disulfide(relative amount 55.86%).The main components of B.campestris grinding tissue volatiles was 3-hexen-1-ol,(Z)-(relative amount 54.14%).Dimethyl disulfide(DMDS),dimethyl trisulfide(DMTS) and allyl isothiocyanate(AITC),which belonged to sulfoether and isothiocyanate,had antimicrobial activities against P.notoginseng pathogens,and the inhibitory activity order was as follows:AITC>DMDS>DMTS.The inhibitory rates of DMDS against strains F-3,D-1,and RS006 were 35.24%,73.23% and 52.19% respectively at concentration of 1200 mL/m3. The inhibitory rates of DMTS against strains F-3 and RS006 were 61.55% and 78.71% at concentration of 50 mL/m3,and the inhibitory rate of DMTS against strain D-1 was 100.00%.The inhibitory rates of AITC against strains F-3 and RS006 were 53.85% and 79.39% at concentration of 8 mL/m3,and it completely inhibited the growth of strain D-1 at concentration of 2 mL/m3.ConclusionDMDS,DMTS and AITC in the B.campestris volatiles inhibitoty effects on the pathogens.The results imply that B.campestris-P.notoginseng rotation or biological fumigation on soil could be dveloped as a method to control P.notoginseng root rot.