Protoplast Formation of Collectotrichum acutum and the Assessment of Antifungal Activity of Several by using its Protoplasts

To obtain protoplasts of Colletotrichum acutatum JC24, conidia were inoculated onto cellophane membrane placed on PDA and incubated at $25^{\circ}C$ for 20 hrs under the dark condition. Cellophane membranes, where mycelia were incubated, were soaked into 2% lysing enzyme solution prepared with 0.02 M phosphate buffer (pH 7.0) including 1.2 M sorbitiol. After treatment in 2% enzyme solution for 2 - 3 hrs, it could be possible to harvest $2-3\;{\times}\;10^6$ protoplasts/mL. The effect of several fungicides on reversion ratio was determined by using the protoplasts obtained from C. acutatum JC24. Any protoplasts could not be reversed to mycelia on reversion PDA amended with $10\;{\mu}\;g\;mL^{-1}$ of propineb. With tebuconazole, inhibition ratio of protoplast reversion was 100 and 0.9% at 0.5 and $0.1\;{\mu}\;g\;mL^{-1}$, respectively, while inhibitory effect on mycelial growth was 85.1 and 75.7%. The inhibitory tendency of carbendazim on protoplast reversion was as same as mycelial growth. In the case of strobilurins, trifloxystrobin and kresoxim-methyl, they only could inhibit protoplast reversion of C. acutatum JC24, when salicylhydroxamic acid (SHAM) was amended into reversion PDA with strobilurins.

고추 탄저병군(Colletotrichum acutatum)의 원형질체 형성과 원형질체를 이용한 살균제 효과 검정

고추 탄저병균인 Colletotrichum acutatum JC24는 PDA 배지에 치상한 cellophane막에 포자 접종하여 $25^{\circ}C$의 암상태에서 20시간 배양한 균사체를 2%의 lysing enzyme에 2-3시간 처리하여 $2-3\;{\times}\;10^6$ 개/mL의 원형질체를 수확할 수 있었다. 이때에는 0.02 M phosphate buffer(pH 7.0)와, 삼투압 안정제로는 1.2 M sorbitol용액을 사용하였을 때가 원형질체의 생성량이 가장 높았다. C. acutatum JC24의 균사체에서 얻은 원형질체에 propineb를 $10\;{\mu}\;g\;mL^{-1}$를 처리하였을 경우에, 균사생장 억제효과는 미미하였지만 원형질체의 재생은 100% 억제하였다. Tebuconazole의 재생 억제효과는 균사생장 억제효과와는 큰 차이를 보였는데, $0.5\;{\mu}\;g\;mL^{-1}$ 처리구에서는 원형질체의 재생이 100% 억제되었고, $0.1\;{\mu}\;g\;mL^{-1}$ 처리구에서는 0.9%밖에 억제하지 못하였다. 하지만 동일한 농도에서 균사생장에 대한 억제효과는 85.1과 75.7%로 억제의 경향이 매우 달랐다. Carbendazim의 경우에는 원형질체 재생과 균사생장에 미치는 효과가 비슷하였다. Trifloxystrobin과 kresoxim-methyl을 SHAm과 동시에 처리하였을 원형질체의 재생에 대한 억제 효과가 크게 상승하였다.