巫山脆李褐腐病病原菌鉴定及1-MCP对其的防治效果

Pathogenic fungus identification of Wushan plum brown rot and bio-control effects of 1-MCP

【目的】鉴定巫山脆李褐腐病病原菌,并通过体内实验(in vivo)探究保鲜剂1-甲基环丙烯(1-methylcyclopropene,1-MCP)对其的抑制效果,为巫山脆李采后病害防治提供理论依据。【方法】根据柯赫氏法则对采集到的发病果实进行病原菌的分离、鉴定及致病性的测定,并将分离纯化得到的褐腐病病原菌采用损伤接种菌饼的方法接种到脆李果实上,探究1-MCP处理对巫山脆李不同时期接种褐腐病的抑制效果及果实硬度的影响。【结果】通过病原菌形态学特征观察、真菌通用引物ITS1和ITS4结合PCR技术,鉴定出引起脆李褐腐病的病原菌为美澳型核果链核盘菌(Monilinia fructicola)。1-MCP处理可显著降低(P<0.05)4℃贮藏期间处理前、处理后、损伤后经1-MCP处理再接种褐腐病的脆李果实的发病率并抑制病斑直径的扩展;25℃条件下,1-MCP处理对不同时期损伤接种脆李果实褐腐病的抑制作用不显著,仅能维持在24 h内;病原菌在25℃贮藏条件下对脆李的致病性强于4℃贮藏条件;常温、低温条件下,1-MCP处理均可有效延缓脆李果实硬度的下降。【结论】明确引起巫山脆李采后褐腐病的病原菌为美澳型核果链核盘菌。1-MCP结合4℃贮藏处理可有效抑制脆李在采后贮藏期间的褐腐病发病率和病斑直径的扩展,并有效维持果实硬度。本研究为巫山脆李采后贮藏过程中褐腐病的发生和防治提供了理论依据。

【Objective】The present paper aimed to identify the pathogen fungus of brown rot of Wushan plum and investigate the inhibitory effect of 1-methylcyclopropene(1-MCP)on it in vivo to provide a theoretical basis for the post-harvest disease control of Wushan plums.【Method】The pathogen fungus was isolated,identified,and pathogenicity tested according to fulfill Koch’s postulate.And the isolated and purified brown rot pathogen fungus was inoculated onto plum fruits by damage inoculation to investigate the inhibition effect of 1-MCP treatment on the inoculation of brown rot at different times and fruit firmness in Wushan plum.【Result】The pathogenic fungus was identified as Monilinia fructicola by morphological characterization,fungal universal primers ITS1 and ITS4 combined with PCR technique.During storage at 4℃,the incidence of disease and the expansion of spot diameter were suppressed(P<0.05)in plum fruit inoculated pathogenic bacteria before/after 1-MCP treatment and after injury,1-MCP treatment was performed before inoculation with pathogenic bacteria.The inhibitory effect of 1-MCP treatment on brown rot of plum fruit inoculated with pathogen fungus at different periods was not significant at 25℃and was maintained only for 24 hours.Pathogen fungi were more pathogenic to plums under storage at 25℃than under storage at 4℃.The 1-MCP treatment was effective in delaying the decline of plums fruit firmness under both ambient temperature and low-temperature conditions.【Conclusion】The pathogen fungus causing postharvest brown rot of Wushan plums was identified and analyzed as M.fructicola,1-MCP combined with 4℃storage treatment effectively inhibited the incidence of brown rot and the expansion of spot diameter of plums during postharvest storage,and effectively maintained fruit firmness.The study provides a theoretical basis for the occurrence and control of brown rot during post-harvest storage of Wushan plums.