Activation of phenylpropanoid pathway and PR of potato tuber against Fusarium sulphureum by fungal elicitor from Trichothecium roseum.

The induced resistance of potato tuber (Solanum tuberosum cv. Xindaping) tissue against Fusarium sulphureum by a fungal elicitor from the incompatible pathogen Trichothecium roseum and its possible mechanism were studied. The results showed that the lesion development of the wound-inoculated potato tuber was significantly reduced by treatment with the fungal elicitor from T. roseum (P < 0.05). Inoculation with F. sulphureum on the 16th day after treatment with the fungal elicitor80 at 15.0 μg/ml had the best resistant effect in the potato tuber, with the diameter being only reduced by 47 % that of the control. In addition, the results also showed that the potato tuber treated with the fungal elicitor80 could systemically induce lignin deposition, total phenolic content, flavonoid content and defense enzymes, including three keys phenylpropanoid pathway (PAL, 4CL and C4H) and pathogenesis-related (GLU and CHT) enzymes. The fungal elicitor80 also enhanced the up-regulation of the transcription and expression of PAL, C4H, 4CL, GLU and CHT genes. The treatment with the fungal elicitor80 + F. sulphureum caused the marked and/or prompt enhancement of all indexes when compared to treatment with the fungal elicitor80 or inoculation with the pathogen alone. The results suggested that the fungal elicitor of T. roseum could significantly enhance defense responses in potato tuber against dry rot mainly due to the up-regulation of the transcription and expression of resistance-related genes as well as increasing the activity of resistance-related enzymes and antifungal compounds.