Analyses of the Less Benzimidazole-sensitivity of the Isolates of Colletotrichumspp. Causing the Anthracnose in Pepper and Strawberry

Kim, Yun Sik; Min, Ji Young; Kang, Beum Kwan; Bach, Ngyeun Van; Choi, Woo Bong; Park, Eun Woo; Kim, Heung Tae

The Plant Pathology Journal 2007;23(3):187-192.
Published online September 30, 2007.

Analyses of the Less Benzimidazole-sensitivity of the Isolates of Colletotrichumspp. Causing the Anthracnose in Pepper and Strawberry

Yun Sik Kim, Ji Young Min, Beum Kwan Kang, Ngyeun Van Bach, Woo Bong Choi, Eun Woo Park, Heung Tae Kim

Abstract

The anthracnose disease on pepper fruits in Korea was caused by Colletotrichum acutatum as well as C. gloeosporioides. Since C. acutatum showed less sensitivity to benomyl, it was analyzed whether the less sensitivity was given by the same mechanism for the fungicide resistance of C. gloeosporioides. The isolates of C. acutatum were less sensitive to the three benzimidazole fungicides tested, benomyl, carbendazim, and thiophanate- methyl. However, the of C. acutatum isolates were different from the resistant isolates of C. gloeosporioides in their response to diethofencarb, one of N-phenylcarbamates; the former was still less sensitive to diethofencarb than the latter. The differences in the resistance mechanisms in two species were conspicuous in sequence analysis of the tub2 genes. The genes from C. acutatum did not show any non-synonymous base substitutions at the regions known to be correlated with the benzimidazole-resistance. All of these data may indicate that the less sensitivity of C. acutatum to benomyl is based on different mechanism(s) from that of C. gloeosporioides.

Key Words: benzimidazole resistance, Colletotrichum acutatum, pepper anthracnose, tub2 sequence