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Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering)  0, Vol. 7 Issue (101): 362-365    DOI: 10.1631/jzus.2006.AS0362
Biotechnological Engineering     
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.

Key wordsPenicillium digitatum      Citrus      Imazalil      Resistance      CYP51 gene     
Received: 02 March 2006     
CLC:  S481+.4  
  S482.2+7  
  S436.661.1+2  
Cite this article:

Zhu Jin-Wen, Xie Qing-Yun, Li Hong-Ye. Occurrence of imazalil-resistant biotype of Penicillium digitatum in China and the resistant molecular mechanism. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 0, 7(101): 362-365.

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http://www.zjujournals.com/xueshu/zjus-a/10.1631/jzus.2006.AS0362     OR     http://www.zjujournals.com/xueshu/zjus-a/Y0/V7/I101/362

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[1] Zhu Jin-Wen, Xie Qing-Yun, Li Hong-Ye. Occurrence of imazalil-resistant biotype of Penicillium digitatum in China and the resistant molecular mechanism[J]. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(Supplement2): 362-365.