红肉火龙果采后病原菌分离鉴定与植物精油抑菌研究

Isolation,Identification and Inhibition of Pathogens from Red Pitaya Fruit during Storage

分离、纯化并鉴定了浙江产区红肉火龙果贮藏期病原菌,筛选出对抑制病原菌效果较好的精油,并验证了该精油抑菌效果。通过分离、纯化及致病性检测,得到了病原菌菌株HS3和HS6。以病原菌18S r DNA序列进行进化树分析,确定两种病原菌为层生镰刀菌和平头炭疽菌。选择6种植物精油进行抑菌性试验,结果发现香芹酚精油、肉桂精油及百里香精油在2 000μL/L时对两种病原菌生长抑制率均为100%。采用体外直接接触法和体外熏蒸法,研究了香芹酚精油、肉桂精油和百里香精油对两种病原菌的抑制效果,发现香芹酚精油表现出较强的抑菌性。无论直接接触还是熏蒸方式,香芹酚精油对层生镰刀菌和平头炭疽菌的抑菌效果均优于肉桂精油和百里香精油。精油熏蒸处理使接种层生镰刀菌和平头炭疽菌火龙果腐烂率下降,香芹酚精油的效果最优,可作为火龙果贮藏前的熏蒸剂。研究结果可为浙江地区火龙果贮藏期腐烂病害的预防和控制提供一定的参考依据。

Red pitaya fruit is highly susceptible to fungal infection during postharvest,causing quality deterioration and huge economic losses. This research was intended to isolate,purify and identify the pathogens which cause rotting of red pitaya during storage in Zhejiang Province,screen essential oils for controlling the pathogenic isolates, and test their effectiveness. HS3 and HS6 were identified as pathogens through isolation,purification and pathogenicity tests. These two strains were proved as F. proliferatum and C. fructicola by morphological identification and r DNA-ITS molecular identification.Six essential oils were investigated for their activity to control these pathogens. The result indicated that carvacrol,cinnamon and thyme oil showed complete inhibitory effect on all pathogens at a concentration of 2 000 μL/L. Then,the inhibitory effects of carcanol,cinnamon and thyme oil on these two pathogens were studied by direct contact in vitro and in vitro fumigation. It was found that carcanol showed higher antifungal activity against F. proliferatum and C. fructicola than cinnamon and thyme in the drug sensitivity test. Moreover,essential oil fumigation inhibited the decay incidence of pitaya fruit inoculated with F. proliferatum and C. fructicola during storage at 4℃ and carcanol showed the best effect.Carcanol oil seemed to be a promising potential fumigant. The results can provide reference for disease control during storage of red pitaya in Zhejiang Province.