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Monilinia fructicola is an economically important pathogen, causing brown rot on many fruit trees. Previous studies revealed that the resistance in this pathogen to thiophanate-methyl was associated with multiple amino acid variations in the Tub2 protein. To understand the temperature adapatability and the activity of diethofencarb in differrent types of isolates, the sensitivities to thiophanate-methyl, carbendazim and diethofencarb were investigated in the sensitive type isolates S and three types of resistant isolates including R(E198A), R(E198Q) and R(F200Y), among which the cross-resistance of different types to MBCs and diethofencarb were analyzed. The results showed that the optimum growth temperature of the four types was ranged from 21 to 22 ℃, among which the R(E198Q) isolates had the lowest optimum growth temperature, and its growth rate was significantly smaller than the other three types under the conditions of 13 ℃ and 28 ℃. While no significant difference was observed in the growth rate of S, R(E198A) and R(F200Y) isolates under all temperature conditions. The three resistant types showed different sensitivities to thiophanate-methyl, among which the R(E198Q) type was least resistant, and the R(F200Y) type was no difference from the R(E198A) type at low concentration but significantly less resistant under high concentration of thiophanate. The difference in sensitivity of three resistant types to carbendazim was similar to that of thiophanate-methyl, only in which the R(E198Q) and R(F200Y) types were more sensitive to carbendazim than thiophanate-methyl. The sensitivity test to diethofencarb showed that the R(E198A) isolates were sensitive, and S isolates were insensitive, while the other two types of R(E198Q) and R(F200Y) showed resistance with little difference. The results of linear correlation analysis showed a significant negative correlation between the sensitivity to benzimidazole fungicides and diethofencarb only in R(E198A) type and S type, (thiophanate-methyl and diethofencarb: r =−0.992, p = 0.000; carbendazim and diethofencarb: r = −0.982, p = 0.001). All the results mentioned above showed that only the R(E198A) type had negative cross-resistance to methyl-benzimidazole carbamates (MBCs) and diethofencarb among the three types of resistant isolates. [ABSTRACT FROM AUTHOR]

Monilinia fructicola is an important pathogen, causing brown rot in many fruit trees. Carbendazim is an effective fungicide for the control of this disease. In order to clarify the sensitivity of M. fructicola to carbendazim, and to understand the the genetic structure of this pathogen originated from different hosts, the sensitivities of 17 isolates from cherry, plum and peach were investigated in this study. The genetic diversity and genetic differentiation of 32 M. fructicola isolates from cherry and peach were also analyzed accroding to Tub2 nucleotide sequences. The results showed that the proportion of isolates with EC50 < 1 μg/mL and > 1 μg/mL was 58.8% and 41.2%, respectively, among which the proportion of isolates with EC50 > 50 μg/mL was 17.6%. The population diversity of M. fructicola from peach was higher than that from cherry, with the nucleotide diversity of 3.25 × 10−3 and 9.04 × 10−3, respectively, and the haplotype diversity of 0.883 and 0.242, respectively. Significant genetic differentiation between the two populations was detected, and the degree of differentiation was medium with the FST value of 0.148. The haplotype network analysis showed that the populations from cherry and peach contained 3 and 9 haplotypes, respectively, within which 2 haplotypes were common. Different haplotypes evolved mainly in two ways. One pathway only showed one haplotype from peach population, and the other haplotypes formed the second pathway through different mutation steps. The host-specific test showed that the isolates from cherry had a certain host specificity, while the isolates from peach were less associated with the host. In conclusion, the resistant frequency of M. fructicola to carbendazim was high and the genetic structure of populations from different hosts was quite diverse. [ABSTRACT FROM AUTHOR]

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Copyright of Chinese Journal of Pesticide Science / Nongyaoxue Xuebao is the property of Chinese Journal of Pesticide Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Modern Medicine & Health is the property of Journal of Modern Medicine & Health and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)