小球藻抗菌物质对苹果果实褐纹病的抗病作用及信号传导机制

The important losses of postharvest apple fruit is Alternaria alternata f.sp mali infection which will lead to Alternaria blotch. Antibacterial substances from Chlorella can resistance Alternaria alternata and have the characteristics of plant activator. This research intends to study the occurrence regularity of Alternaria blotch disease in apple fruit, and establish the general mode and approaches to apple fruit disease. The impact of antibacterial substances from Chlorella on postharvest apple fruit disease was investigated, and its possible interaction response as well as signal induced mechanisms were also be explored. In addition, metablites accumulation, distribution and composition in storage apple fruit were also discussed. The study will provide theoretical foundation for prevention of Alternaria blotch disease in apple fruit and for application technology of control diseases and green production of postharvest apple fruit. Moreover, the antibacterial subtances from microalgae can be employed as a biological preservative for postharvest horticultural products.

褐纹病是目前引起我国苹果果实采后大量损失的重要因素，由苹果链铬孢菌引起。小球藻抗菌物质含有抗链铬孢菌的生物活性功能成分，且具有植物激活剂的相关特性。本项目拟在开展苹果果实褐纹病病害发病模式和途径研究的基础上，研究小球藻抗菌物质对苹果果实采后褐纹病的控制作用及其对果实抗病性的诱导效果，探明苹果果实褐纹病受外源信号物质调控的特点，阐明小球藻抗菌物质-病原菌-果实三者之间可能的互作机制及信号传导的响应模式，并通过探讨小球藻抗菌物质诱抗处理后苹果果实代谢产物的增量累积、组成与分布的变化进一步推测小球藻抗菌物质诱导苹果果实褐纹病抗病性产生的物质基础可能。该研究将为苹果褐纹病的防治提供新的理论依据，为改善苹果果实品质和进行果品绿色贮藏提供重要的应用技术基础，为微藻抗菌活性功能成分作为生物保鲜剂推广应用提供理论参考。

褐纹病是目前引起我国苹果果实采后大量损失的重要因素，由苹果链铬孢菌引起。小球藻抗菌物质含有抗链铬孢菌的生物活性功能成分，且具有植物激活剂的相关特性。研究者对苹果叶片和果实的褐纹病病斑形态进行了调研，并对引起苹果果实褐纹病的链格孢菌形态学进行了研究。利用真菌通用引物ITS1/ITS4 对苹果果实褐纹病病原菌菌株rDNA-ITS 进行PCR 扩增，扩增出一条800 bp大小的片段。将测序获得的序列上传到NCBI 进行BLAST 比较分析，该病原菌菌株的rDNA-ITS 序列与GenBank 中收录的序列进行同源性进行比较，结合形态鉴定结果，确定分离得到的这株病原菌为Alternaria alternata。体外抑菌实验表明：甲醇：甲苯的Spirulina platensis提取液对苹果果实链格孢菌的体外抑制作用比Chlorella zofingiensis提取液的抑制作用强，而乙酸乙酯、丙酮的Chlorella vulgars提取液对苹果果实链格孢菌的体外抑制作用比Chlorella zofingiensis提取液的抑制作用强，正己烷的Chlorella vulgars提取液对苹果果实链格孢菌的体外抑制作用比Spirulina platensis提取液的抑制作用强。体内抑菌实验表明：小球藻活性成分对苹果果实褐纹病具有一定的抑制效果，单一使用小球藻抑菌物质效果不如将小球藻抑菌物质和其他保鲜剂复配的效果。该研究将为苹果褐纹病的防治提供新的理论依据，为改善苹果果实品质和进行果品绿色贮藏提供重要的应用技术基础，为微藻抗菌活性功能成分作为生物保鲜剂推广应用提供理论参考。