紫外光诱导灰葡萄孢产生抗多菌灵菌株的研究

测得多菌灵对Botrytis cinerea野生菌株B_2的最低抑制生长浓度(MIC)值为0.5ppm。然而,经紫外光照射定向诱导,从B_2获得了突变频率为I/0.9—4.5×10~4的抗多菌灵突变菌株。这种抗性菌株在含多菌灵1000ppm的马铃薯蔗糖琼脂培养基上,菌丝生长很少受到抑制,在多菌灵2000ppm情况下仍能生长,难以测定MIC值。诱变抗性菌株(B-UV1)在无药培养基上连续培养8个月,抗性程度仍未下降,但生长速率降低。 B-UV1菌株对苯来持、托布津杀菌剂表现高度的交互抗性,但对克菌丹等4种测试药剂的敏感性,与野生菌株相似。接种草莓时,B-UV1菌株引起的发病率为野生菌株的77.8％,而且病情较轻。

STUDY ON UV-INDUCED RESISTANT STRAINS TO CARBENDAZOL IN BOTRYTIS CINEREA

The minimum inhibitory concentration (MIC) of carbendazol (MBC) to mycelial growth of a wild-type strain B₂ of Botrytis cinerea was 0.5ppm. Mutation frequence from MBC-sensitive (B₂) to resistant strain of B. cinerea, which was induced by UV light, was 1/0.9-4.5×10⁴ spores. The mycelial growth of the UV-induced strain-R was less inhibited on PSA amended with 1000ppm MBC (technical grade product), and it can grow on PSA containing even 2000ppm of the fungicide. Therefore, it is difficult to mesure MIC value. The B-UV1 strain that is one of the UV-induced had been incubated continuously on PSA without fungicide for more than eight monthes, its resistantdegree hadn''t lowered, however, the rate of mycelial growth had decreased.There were highly cross-resistance to benomyl and to thiophanate and similarly sensitivity with wild-strain to captan and others tested fungicides in B-UV1 strain. Spores of B-UV1 strain and a wild-strain of B. cinerea were inoculated flowers, fruits, and petioles of strawberry. Diseased rates caused by B-UV1 were 77.8% as compared with that by the wild-strain, and the disease caused by the latter was more serious than that by the former.