两株生防酵母菌对Colletotrichum gloeosporioides 的抑菌机理研究

Disease control is an important step to ensure agriculture of high-yield, high-quality and high-efficiency. Biological control has become the main way of disease control because of its security, non-toxic and no adverse effects. Antagonism of yeast is attended by researchers all over the world because it does not produce toxins, has genetic stability, high ability of reproduce, and has strong antimicrobial properties. At present，a great deal of research about the antagonistic yeast is in the stage of laboratory, there are very little antagonistic yeast being applied commercially, that is because the mechanism of antagonistic yeast is not so clear, the ideal control effect is difficult to be achieved. Therefore, to explore and study the mechanism of antagonistic yeast, to improve antagonistic yeast purposely, which is the key for enhancing the control effect and applying antagonistic yeast extensively in practice. In this study, two inhibitory actions—Nepal and Barry yeast strains, which was selected and screened from soil of mango garden in Hainan by our research group, will be conducted to study the interactions between antagonistic yeast strains and main postharvest disease - anthracnose of mango fruit, the inhibition mechanism of two strains shall be explored and studied from the aspects of heavier parasitic effect, competition effect, antibacterial substances and induced resistance. This study has important theoretical and practical significance for applying antagonistic yeast in storage and transportation of fresh mango, and improving the quality and reducing the loss of fresh mango fruit.

病害防治是农业生产安全、优质、高效的重要环节。生物防治以其安全、无毒、无副作用已成为病害防治的主要方式。拮抗酵母菌因其不产生毒素、遗传稳定、繁殖能力强、抗菌性强等优点受到国内外普遍关注。但目前有关拮抗酵母菌的研究多处于实验室理论研究，能够商业化规模应用的较少。其原因是由于拮抗机理不清楚，难以达到理想的防治效果。因此,探讨和研究拮抗酵母菌的防治机理,有针对性的对拮抗酵母菌进行改良,是提高拮抗酵母菌防治效果并将之广泛应用的关键。本研究以课题组从海南芒果园土壤中筛选鉴定的梅奇美及酵母和尼泊尔德巴利酵母为供试拮抗菌株,研究其与芒果采后主要病害--芒果炭疽病的相互作用,并从重寄生作用、竞争作用、抑菌代谢物质产生及抗性诱导四个方面研究和探讨两个菌株的抑病机理，此研究对于将拮抗酵母菌应用于芒果贮运保鲜、改善和提高芒果品质、减少病害损失具有重要的理论与实践意义。

芒果采后主要的病害为芒果炭疽病，生物防治以其安全、无毒、无副作用已成为采后病害防控研究热点，本项目以实验室前期从芒果园土壤中分离得到的美极梅奇酵母和尼泊尔德巴利酵母为研究对象，评估了两株拮抗酵母对芒果病原菌Colletotrichum gloeosporioides抑制的有效性并阐明了抑菌机理；同时从绿色安全环保的化学试剂中筛选出了对美极梅奇酵母拮抗胶孢炭疽菌有增效作用的物质；另外以尼泊尔德巴利酵母与实验室分离得到的汉逊德巴利酵母、和萎缩芽孢杆菌进行复合，研究复合菌株对芒果贮藏品质和抗病性的影响，筛选了复合菌株保护剂，研究了复合菌株保鲜剂的研制。研究结果表明：两株拮抗菌通过竞争营养物质和生存空间，有效抑制了病原菌的生长；两株拮抗菌都具有形成生物膜的能力，在芒果表面形成保护膜，防止病原菌的侵入；通过平板对峙实验和GC-MS发现两株拮抗菌产生了抑菌物质；两株拮抗菌均可诱导芒果果实中抗性相关酶I活性的增加；两株拮抗菌均可分泌水解酶（β-1,3-葡聚糖酶），其中美极梅奇酵母还可以分泌胞外几丁质酶；增效剂CMC-Na、MeJA、SA组合（AEB）结合美极梅奇酵母可提高抑菌效果；获得了一种新型的复合生物保鲜剂（C-Y-TE+茶多酚+脱脂奶粉）冻干粉。