拮抗多花黄精根腐病的内生真菌鉴定及发酵条件研究OACSTPCD

The root rot of Polygonatum cyrtonema is a major risk factor that restricts its yield and quality.In order to explore a green and effective biological control pathway for this disease,this study used tissue isolation method to obtain the endophytic fungal strain HJ-53 and the pathogenic fungi of P.cyrtonema root rot.Based on morphological characteristics and ITS/TEF sequence analysis,the fungal strain HJ-53 was identified as Penicil-lium citrinum;the pathogen of the root rot of P.cyrtonema was Fusarium oxysporum,which had been validated by the Koch rule.The antifungal activity of strain HJ-53 and the ethyl acetate extract from the fermentation broth were preliminarily determined using plate confrontation cultivation and growth rate methods.The optimal basic culture medium and fermentation conditions for the strain were screened using single factor and orthogonal ex-periments.The results showed that the endophytic fungus HJ-53 had strong antifungal activity,and its two points and five points confrontation cultivation had antifungal rates of 54.81％and 61.04％,respectively;the ethyl ace-tate extracted from the fermentation broth of the strain with a concentration of 10 g L-1 had a high antifungal rate of 73.20％.The optimal fermentation medium for this endophytic fungus was glucose 30 g·L-1,peptone 15 g·L-1,and calcium chloride 1.5 g·L-1;the optimal fermentation conditions were fermentation for five days,fermentation temperature of 25 ℃,shaking bed speed of 180 r-min-1,and pH value of 7.The results showed that the endo-phytic fungal strain HJ-53 has certain biocontrol potential,which provides a theoretical basis and strain resources for the research of biocontrol agents for the root rot disease of P.cyrtonema.