Expression of a Maize Myb Transcription Factor Driven by a Putative Silk-Specific Promoter Significantly Enhances Resistance to Helicoverpa zea in Transgenic Maize

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• 作者：Eric T. Johnson ; Mark A. Berhow ; Patrick F. Dowd
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2007
• 出版时间：April 18, 2007
• 年：2007
• 卷：55
• 期：8
• 页码：2998 - 3003
• 全文大小：243K
• 年卷期：v.55,no.8(April 18, 2007)
• ISSN：1520-5118

文摘

Hi II maize (Zea mays) plants were engineered to express maize p1 cDNA, a Myb transcription factor,controlled by a putative silk specific promoter, for secondary metabolite production and corn earwormresistance. Transgene expression did not enhance silk color, but about half of the transformed plantsilks displayed browning when cut, which indicated the presence of p1-produced secondarymetabolites. Levels of maysin, a secondary metabolite with insect toxicity, were highest in newlyemerged browning silks. The insect resistance of transgenic silks was also highest at emergence,regardless of maysin levels, which suggests that other unidentified p1-induced molecules likelycontributed to larval mortality. Mean survivor weights of corn earworm larvae fed mature browningtransgenic silks were significantly lower than weights of those fed mature nonbrowning transgenicsilks. Some transgenic pericarps browned with drying and contained similar molecules found inpericarps expressing a dominant p1 allele, suggesting that the promoter may not be silk-specific.