Biotechnological Engineering |
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Occurrence of imazalil-resistant biotype of Penicillium digitatum in China and the resistant molecular mechanism |
Zhu Jin-Wen, Xie Qing-Yun, Li Hong-Ye |
Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310029, China; Institute of Biotechnology, Zhejiang University, Hangzhou 310029, China |
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Abstract Green mold caused by Penicillium digitatum (Pers.:Fr) Sacc. is one of the most important postharvest diseases of citrus fruits. Experiments were conducted to determine the occurrence of resistance of P. digitatum to imazalil in China. Four imazalil-Resistant (R) isolates were identified from 189 isolates of P. digitatum. The highest EC50 of an imazalil-R isolate was 0.578 mg/L, 29 times higher than that of the most imazalil-sensitive (S) isolate, suggesting that imazalil-R biotype of P. digtatum had occurred in China. In vitro assessment indicated that the imazalil-R isolates were not significantly different from imazalil-S isolates in their growth rate and sporulation, indicating that the imazalil-R biotype has competence similar to that of imazalil-S one and could co-exist with it in environment. To determine the mechanism of the resistance, CYP51 gene was amplified from P. digitatum genome and sequenced. The results revealed that a tandem repeat of four extra copies of a unique 126-bp sequence in the upstream promoter region of CYP51 gene present only in imazalil-R isolates, but not in imazalil-S isolates, implying this tandem repeat sequence may regulate the expression of CYP51 positively, and lead to the sensitivity decrease.
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Received: 02 March 2006
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[1] |
de Waard, M.A., van Nistelrooy, J.G.M., 1990. Stepwise development of laboratory resistance to DMI-fungicides in Penicillium italicum. Neth. J. Plant Pathol., 96(6):321-329.
doi: 10.1007/BF01998780
|
|
|
[2] |
Délye, C., Laigret, F., Corio-Costet, M.F., 1997. Cloning and sequence analysis of the eburicol 14alpha-demethylase gene of the obligate biotrophic grape powdery mildew fungus. Gene, 195:29-33.
doi: 10.1016/S0378-1119(97)00141-8
|
|
|
[3] |
Eckert, J.W., 1987. Penicillium digitatum biotypes with reduced sensitivity to imazalil (Abstr.). Phytopathol., 77:1728.
|
|
|
[4] |
Eckert, J.W., Sievert, J.R., Ratnayake, M., 1994. Reduction of imazalil effectiveness against citrus green mold in California packagehouse by resistant biotypes of Penicillium digitatum. Plant Dis., 78:971-974.
|
|
|
[5] |
Hamamoto, H., Hasegawa, K., Nakaune, R., Lee, Y.J., Makizumi, Y., Akutsu, K., Hibi, T., 2000. Tandem repeat of a transcriptional enhancer upstream of the sterol 14alpha-demethylase gene (CYP51) in Penicillium digitatum. Appl. Environ. Microbiol., 66(8):3421-3426.
doi: 10.1128/AEM.66.8.3421-3426.2000
|
|
|
[6] |
Harding, P.R.Jr, 1976. R23979, a new imidazole derivative effective against postharvest decay of citrus by molds resistant to thiabendazole, benomyl, and 2-aminobutance. Plant Dis. Rep., 60:643-646.
|
|
|
[7] |
Holmes, G.J., Eckert, J.W., 1995. Relative fitness of imazalil-resistant and sensitive biotypes of Penicillium digitatum. Plant Dis., 97:1068-1073.
|
|
|
[8] |
Holmes, G.J., Eckert, J.W., 1999. Sensitivity of Penicillium digitatum and P. italicum to postharvest citrus fungicides in California. Phytopathol., 89:716-721.
|
|
|
[9] |
Ma, Z., Michailides, T.J., 2005. Advances in understanding molecular mechanisms of fungicide resistance and molecular detection of resistant genotypes in phytopathogenic fungi. Crop Protect., 24(10):853-863.
doi: 10.1016/j.cropro.2005.01.011
|
|
|
[10] |
Nakaune, R., Adachi, K., Nawata, O., Tomiyama, M., Akutsu, K., Hibi, T., 1998. A novel ATP-binding cassette transporter involved in multidrug resistance in the phytopathogenic fungus Penicillium digitatum. App. and Environ. Microbiol., 64:3983-3988.
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