拮抗菌对致病疫霉生长及抗性酶活性的影响

Effects of antagonistic microorganisms on growth and resistance enzymes activities of Phytophthora infestans

为获得更为有效的致病疫霉拮抗菌并探讨拮抗菌的作用机理,本研究利用对峙培养法、滤纸片法测定了10个待测菌株的活体及发酵液的抑菌作用,用分光光度法测定了受显著抑制后再恢复生长的致病疫霉体内多酚氧化酶（PPO）、过氧化物酶（POD）和苯丙氨酸解氨酶（PAL）的活性。结果表明：活体状态下以核桃细菌的抑制作用最强（抑菌率为84.50%）;发酵液中以梨黑斑病菌（Alternaria alternate）的抑制作用最强（抑菌率为76.68%）,其次是白菜黑斑病菌（A.brassicae）。将梨黑斑病菌和白菜黑斑病菌的发酵液复配后其抑菌率达到了81.31%。受抑制的致病疫霉菌落中紧靠抑菌带边缘的菌丝不能恢复正常生长,较远的菌丝易恢复正常生长;受抑制的致病疫霉体内PPO、POD、PAL活性均明显降低,与对照相比,PPO活性下降了45%~68%,POD下降了27%~58%,PAL下降幅度最大,约80%~90%,这与植物受病菌抑制或侵染后PPO、POD、PAL活性增加相反。

To obtain much more effective antagonistic microorganisms against Phytophthora infestans and explore their mechanisms,inhibition activities of living organisms and fermentations of 10 strains on mycelial growth were tested through dual culture methods and filter paper methods,and the activities of some resistant-related enzymes in restrained P.infestans were measured using the UV-Vis Spectrophotometer.The results showed that a strain isolated from shoots of walnut displayed the strongest inhibition effect with inhibition rate of 84.50% among 10 living bodies,while the fermentation of Alternaria alternate exhibited the best suppression with inhibition rate of 76.68%,followed by that of A.brassicae with 47.92%.However,the repression of compound one composed of fermentation of A.alternate and A.brassicae as 1∶1 ratio of original concentration was much better with inhibition rate of 81.31%.In addition,mycelia located near to inhibition zone could not grow again,but that far from inhibition zone could grow again.The peroxidase（POD）,polyphenoloxidase（PPO）,and phenylalanine ammonia-lyase（PAL） in restrained fungus decreased evidently,especial PAL decreased by 80%-90% in compound fermentation treatment compared with control.