Screening，identification of antagonistic yeast and its biocontrol efficacy against green mold caused by Penicillium digitatum of citrus fruit | 柑橘采后绿霉病生防酵母菌的筛选、鉴定及其生防效果研究

Chinese. 筛选能有效防治柑橘采后绿霉病菌（Penicillium digitatum）的拮抗酵母菌，为柑橘的采后保鲜提供参考。从园艺果园采集不同的水果样品，用稀释平板法分离筛选生防酵母菌株，并进行鉴定；采用PDB液体培养试验和刺伤接种的方法，研究不同浓度酵母菌悬浮液对离体和活体柑橘绿霉病菌的防治效果。获得1株拮抗酵母菌HP-10，结合生理生化特性及18S rDNA序列同源性分析，将其鉴定为马克斯克鲁维酵母（Kluyveromyces marxianus）。离体和活体抑菌试验表明，菌株HP-10悬浮液能有效抑制绿霉病菌孢子的萌发；用108 CFU/mL HP-10悬浮液处理病原菌孢子时，其萌发率仅为3.61%，而对照的萌发率为88.06%；25 ℃条件下，用108 CFU/mL的酵母悬浮液处理柑橘果实2 d后，发病率仅为6.67%，病斑直径仅为2.14 mm,显著低于对照的发病率（93.33%）和病斑直径（53.31 mm）。不同浓度HP-10菌悬液对柑橘绿霉病菌均具有一定的防治效果，表现出良好的生防潜力。

English. The study focused on isolating and characterizing yeast with abilities to control diseases of citrus fruits, to provide an alternative strategy to control postharvest disease of citrus fruits. An antagonistic yeast HP-10 was preliminarily identified as Kluyveromyces marxianus based on physiological-biochemical characteristics and the similarity analysis of its 18S rDNA sequence. The efficacy of HP-10 to Penicilluium digitatum in vitro and in vivo was studied by PDB trials and wounding inoculation. The spore germination of P. digitatum was significantly inhibited by the yeast cell suspensions in the tests on potato dextrose broth (PDB). High efficacy was achieved when fruits were treated with suspension of HP-10 at 108 CFU/mL. Disease incidence was reduced by 84.45% compared with control after 2 days incubation. When antagonistic yeat K. marxianus was treated at a concentration of 108 CFU/mL under 25 ℃ for 2 days, the decay incidence occured by 6.67% and lesion diameter 2.14 mm, while the control fruits had 93.33% disease incidence and 53.31 mm lesion diameter. It was suggested that HP-10 had a great potential to control green mold of citrus fruit, and can be used as a new strategy for the biocontrol of postharvest diseases.