Studies on the Production of Phytotoxins and Their Application for Plant Protection

植物病原真菌产生许多植物毒素，并且当前对它们在致病性中的作用以及它们的化合物和衍生物在农用化学品中的用途感兴趣。最近，我们已经发现了几种生理活性化合物，甜菜茎点霉的β烯酮和蚜虫烷，茄链格孢的茄吡喃酮，芦笋茎点霉的高氧菌素，以及用Cepulosporium gregatum B型处理的红豆中的甜菜碱和酚类化合物。研究工作概要如下。(1)在甜菜糖汁培养基中蚜虫烷的产量增加。研究了马铃薯-蔗糖培养基中茄那吡喃酮A的生物合成，结果表明，茄那吡喃酮A的生物合成是通过奥克他肽途径进行的。(2)通过（+）-diplodiatoxin和（-）-betaenone C的全合成，可以制备出各种类似物，这些类似物可用于结构-生物活性关系的研究和生物合成中间体的掺入。对高替罗辛A的植物毒性代谢产物和合成中间体进行了毒素抗性细胞的筛选，以产生抗性愈伤组织。(3)以赤豆为材料，用引起赤豆茎腐病的病原真菌弱毒力菌株--头孢霉B处理赤豆根，分离并鉴定了抗真菌胁迫化合物。这些化合物主要为异黄酮类化合物。

Plant Pathogenic fungi produce a number of phytotoxins and there is current interest in their roles in pathogenicity as well as in the use of their compounds and derivatives for agrochemicals. Recently, we have found several physiologically active compounds, betaenones and aphidicolanes from Phoma Betae, solanapyrones from Alternaria Solani, altiloxins from Phoma Asparagi, and isoflavonoids and phenolic compounds from azuki bean treated with Cephalosporium gregatum Type B. Outline of research work is summarized as follows.(1) Production of aphidicolanes increased in the culture medium of beet sugar juice. Biosynthetic study of solanapyrone A on potato-sucrose medium revealed that the phytotoxin is biosynthesized through octaketide pathway.(2) Total synthesis of(+)-diplodiatoxin and then (-)-betaenone C have made possible to prepare various analogues which are useful for the studies of structure-bioactivity relationship and incorporation in biosynthetic intermediates. Selection of toxin- resistant cells for phytotoxic metabolites and synthetic intermediates of altiloxin A has been carried out to give resistant calli.(3) Antifungal stress compounds were isolated and identified from the roots of adzuki bean that had been treated with Cephalosporium type B, which is an avirulent strain of a pathogenic fungus causing brown stem rot disease on the host plant. These compounds were mainly isoflavones.