کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10824461 | 1062369 | 2005 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Characterization of cDNAs encoding three trypsin-like proteinases and mRNA quantitative analysis in Bt-resistant and -susceptible strains of Ostrinia nubilalis
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش حشره شناسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Our previous studies suggested that Bacillus thuringiensis (Bt) resistance in a Dipel-resistant strain of Ostrinia nubilalis was primarily due to reduced trypsin-like proteinase activity. In this study, we demonstrated a 254-fold resistance to Cry1Ab protoxin but only 12-fold to trypsin-activated Cry1Ab toxin in the Dipel-resistant strain. Significantly higher resistance to Cry1Ab protoxin than to trypsin-activated Cry1Ab toxin further supports the hypothesis that reduced trypsin-like proteinase activity leading to reduced activation of the Bt protoxin is a major resistance mechanism in the Dipel-resistant strain. To understand the molecular basis of reduced proteinase activity, three cDNAs, OnT2, OnT23, and OnT25, encoding full-length trypsin-like proteinases, were sequenced in Bt-resistant and -susceptible O. nubilalis larvae. Although a number of nucleotide differences were found in sequences from the Bt-resistant and -susceptible strains, the differences were not consistent with reduced trypsin-like activity in the Bt-resistant strain. However, the mRNA levels of OnT23 in the resistant strain were 2.7- and 3.8-fold lower than those of the susceptible strain as determined by northern blotting and real-time quantitative PCR, respectively. Thus, reduced trypsin-like activity may be attributed to reduced expression of OnT23 in Bt-resistant O. nubilalis. Our study provides new insights into Bt resistance management strategies, as resistance mediated by reduced Bt protoxin activation would be ineffective if resistant insects ingest a fully activated form of Cry1Ab toxin, either in spray formulations or transgenic Bt crops.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Insect Biochemistry and Molecular Biology - Volume 35, Issue 8, August 2005, Pages 847-860
Journal: Insect Biochemistry and Molecular Biology - Volume 35, Issue 8, August 2005, Pages 847-860
نویسندگان
Huarong Li, Brenda Oppert, Randall A. Higgins, Fangneng Huang, Lawrent L. Buschman, Jian-Rong Gao, Kun Yan Zhu,