草莓黑斑病菌所产毒素的研究进展

The Research Advances to the AF-Toxin Produced by Alternaria fragariae

草毒黑斑病菌所产生的毒素（AF-毒素）是一种寄主选择性毒素，它只对Morioka-16草毒和Nijisseiki梨具有致病作用，它含有Ⅰ，Ⅱ，Ⅲ3个组份，其中Ⅰ，Ⅱ为主要组份，Ⅱ对Ⅰ具有保护作用，3个组份的化学结构和致病力都不完全相同。AF-毒素在草毒黑班病的发生过程中诱导寄主感病性，破坏寄上细胞，造成细胞膜内折破裂，电解质渗漏，膜电位改变，造成与接种草毒黑斑病菌类似的症状。AF-毒素在孢子萌发过程中产生，同时在孢子萌发液中还存在一种高分子诱导物，它能激发寄主的抗病机制（预先处理）。一些化学物质如丝氨酸（Cer），甲硫氨酸（L-Met）能抑制AF-毒素的产生，这些都为生物防治提供了新的思路。

That AF - toxin produced by Alternaria fragriae causes the black spot ofstrawberry is a bost -selective toxin which is only pathogenic to strawberry cv. Morioka-16 and Japanese pear cv- Nijisseiki. The toxin comprises parts Ⅰ, Ⅱ andⅢ,with partiallydifferent chemical structures and pathogenicity. AF-toxin Ⅰis under protection of the AF-toxin Ⅱ. AF-toxin induces susceptibility of the host and destroys host cell,resulting inplasma membrane invagination and damage, electrolyte leakage and electric potential ofmembrane change. The toxin causes the similar symptoms to those by A. fragariae. AFtoxin is produced during the spore germination of the pathogen' Another kind of highmolecular 'ninducer' is also found in the germination fluids of spores,which can induce theresistance of the host to the AF-toxin with pre - inoculation' Some chemicals such as Cer,L-Met can suppress the production of AF-toxin. All these show potential for biologicalcontrol of the disease.