油桐根腐病病原菌的研究

A NEW FORMA SPECIALES OF FUSARIUM SOLANI CAUSING ROOT-ROT OF TUNG-OIL TREE

油桐根腐病是油桐林的一种毁灭性病害。形态学和培养性状研究表明,致病菌为腐皮镰孢(Fusarium solani(Mart.)Sacc.)。将该菌与国内供试8个腐皮镰孢专化型菌株比较可看出,菌落生长较快,大型分生孢子短而粗,是一种短粗类型。其次,人工接种试验得知,此菌不侵染6科7属7种供试的专化型寄主植物;又经8个专化型菌株接种油桐试验,也不发生侵染关系。此菌仅侵害大戟科油桐属的油桐,是一种专化性病菌。再次,采用聚丙烯酰胺凝胶电泳分析表明,此菌与供试菌株的脂酶同工酶的谱带特征和相对迁移率均有明显的差异。由此,将油桐根腐病鉴定为腐皮镰孢一新的专化型,命名为油桐腐皮镰抱(Fusarium solani (Mart.) Sacc. f.sp.aleuritidis Chen et Xiao f.sp.nov.)

Root-rot is a destructive disease in the tung-oil tree (Aleurites fordii Hemsl.) of Sichuan. The causal fungus identified as Fusarium solani (Mart.) Sacc. was isolated from diseased tung-oil tree roots.Studies on morphology and cultural characteristics indicate that there are many differences between this root-rot fungus and other 8 forma speciales of F. solani from different hosts in China in the size of macrospores and the rate of growth.Test on pathogenisity confirmed that the pathogen is pathogenic to host plant and inoculation experiments of 7 species plants were negative. Artificial inoculation with 8 forma speciales of F. solani to tung-oil tree are unsuccessful.The changes in esterase isozyme of this pathogen and other tested strains was studied with polyacrylamide gel electrophoresis technique. It has been shown that esterase isozyme band, the number and relative rate of migration of the pathogen and all 8 strains could be discriminated.Hence the pathogen of root-rot of tung-oil tree is idefied to be a new forma speciales of F. solani, and is diagnosed as Fusarium solani (Mart.) Sacc. sp. f. aleuritidis Chen et Xiao f. sp. nov.