木霉几丁质酶对烟草赤星病菌的作用

以指形管培养法分别测定几丁质酶粗酶液和纯化的几丁质酶混合液(2种几丁质酶)对烟草赤星病菌孢子萌发的抑制作用。结果表明,较高浓度(25 2U)几丁质酶粗酶液在48h内强烈抑制孢子萌发和芽管伸长,或致芽管畸形和细胞壁破裂;几丁质酶混合液对赤星病菌的孢子萌发也表现出明显的抑制作用,但在相同或相近酶活性条件下,纯化的几丁质酶混合液(9 4U)和粗酶液(12 6U)对赤星病菌孢子萌发的抑制率(处理24h时)分别为46%和84 3%,前者明显低于后者。采用孢子液悬滴法接种烟苗(K 326)叶片测定木霉几丁质酶对赤星病菌致病性的影响。结果表明,几丁质酶粗酶液浓度越高,对孢子萌发抑制时间越长,抑制率越高;其浓度为4 9、9 8、19 5U/ml的抑制率7d时分别为36 8%、56 2%和57 6%。

Role of Chitinase Produced by Trichoderma sp.in Biocontrol of Tobacco Brown Spot Caused by Alternaria alternata

Inhibitions of conidial germination of Alternaria alternata by crude and purified chitinase were determined by finger tube culture method. Results indicated that the germination was strongly inhibited by crude chitinase (25.2U) within 48 h, resulting in complete inhibition of the germination or abnormality and disruption of germination tubes. Purified chitinases also inhibited conidial germination of A. alternata, but in much lower level than that treated with crude chitinase at the similar activity units. The inhibition of conidial germination and pathogenicity of A. alternata to tobacco seedlings was higher and longer with the concentration of the crude chitinase solutions applied. The inhibition rates were 46% and 84.3% when treated at 9.4 and 12.6U after 24 h respectively.