Abstract:
To elucidate the types of
Gastrodia elata brown rot pathogenic fungi and the inhibitory effect of citral on them. Tissue isolation method, pathogenicity test, morphological observation and rDNA-ITS sequence analysis were employed to isolate and identify the pathogenic fungi using naturally-occurring
G. elata as test material. Furthermore, the
in vitro inhibitory effect of citral on the pathogenic fungi at different concentrations and its effect on the induced disease resistance of
G. elata were investigated. Results demonstrated that the primary pathogenic fungi causing brown rot of
Gastrodia elata were
Trichoderma hamatum and
Fusarium tricinctum. The inhibition rate against the pathogenic fungi exhibited a dose-dependent relationship with the concentration of citral, with an MIC value of 0.6 μL/mL. At 3 d post-inoculation, the diameters of the spots of
Trichoderma hamatum and
Fusarium tricinctum were 15.20 and 8.17 mm, respectively. It was determined that
Trichoderma hamatum was the main pathogenic fungi causing brown rot of
Gastrodia elata. Furthermore, the optimal control of
Trichoderma hamatum was achieved by 0.6 μL/mL citral. The application of citral resulted in the accumulation of total phenolic and flavonoid contents, as well as the promotion of an increase in APX, PPO, POD, SOD and CAT enzyme activities in
G. elata. This enhanced the resistance of postharvest
G. elata to
Trichoderma hamatum. The present study is of great significance for the control of brown rot pathogenic fungi of
G. elata and the prolongation of its shelf life.