Induced resistance to TMV in tobacco seedlings with burdock fructooligosaccharide.

In this study,the effects of burdock fructooligosaccharide(BFO) on the control of TMV in tobacco seedlings and the underlying mechanism were investigated in laboratory.The results indicated that in BFO treated leaves(the third leaf),the level of TMV-CP transcripts in distilled water(DW) treated leaves was about 2.6-fold higher than that in the BFO treated leaves 24 h after inoculation with TMV,the relative control effect reached to 61%.In untreated leaves(the fourth leaf),the transcripts of TMV-CP could be detected in DW treated leaves 24 h after inoculation with TMV,but could not be detected in BFO treated leaves.In addition,the results indicated that both treatment with BFO and inoculation with TMV could induce accumulation of transcripts of defense related protein genes,including PR-1a,PR-2,PR-3,PI-1,PI-2 and PAL in both treated and untreated tobacco leaves.These results suggest that BFO could induce resistance to TMV in tobacco leaves.The mechanism might be attributed to the expression of defense related genes which increased the systemic resistance in tobacco seedlings.