The phytotoxins ofMycosphaerella fijiensis,the causative agent of Black Sigatoka disease of bananas and plantains

Black Sigatoka is the most costly to control disease of bananas and plantains in the world. Currently, a worldwide search is underway either to find or to produce cultivars that are disease-resistant or-tolerant. Phytotoxins isolated from the pathogen might facilitate the discovery of such cultivars. Several aromatic compounds from liquid cultures ofMycosphaerella fijiensis, the causal agent of Black Sigatoka disease of bananas and plantains, have been isolated. The most abundant and phytotoxic of these compounds is 2,4,8-trihydroxytetralone, which induces necrotic lesions at 5 g/5 l in less than 12 h on sensitive cultivars of bananas. This compound exhibits host-selectivity that mimics that of the pathogen. Other phytotoxins isolated from this fungus, in lesser amounts, were juglone, the novel compound 2-carboxy-3-hydroxycinnamic acid, isoochracinic acid and 4-hydroxyscytalone. Some of the phytotoxins isolated are melanin shunt pathway metabolites, which makes this fungus unique among plant pathogens.     

胡桃醌合成的新方法

萘经过硝化、氧化生成5-硝基-1，4萘醌，然后硝基还原成氨基、氨基重氮化、重氮盐再水解，最终用新方法制得胡桃醌。光谱数据和熔点与文献值相符。     

青龙衣中胡桃醌的分离与鉴定

从青龙衣中制备高纯度的胡桃醌并对其鉴定.采用硅胶柱层析和半制备高效液相色谱分离纯化胡桃醌,运用气相色谱-质谱法对其进行定性分析,运用高效液相色谱法对制备的胡桃醌进行纯度测定.制备的胡桃醌纯度为98.23％,转移率为10.41％.该法具有纯化效果好、操作高效、快速的特点.可用于胡桃醌的大量制备.