关键词: 苹果, 梨, AFS, 启动子, 顺式作用元件, 虎皮病

Abstract: Both apple（Malus × domestica L.）and pear（Pyrus communis L.）fruits are prone to suffer superficial scald during storage at low temperature. Previous studies have proved that the occurrence of superficial scald is closely related to the α-farnesene synthase gene（AFS）expression and accumulation of α-farnesene in the fruit peel，but little is known about its promoter. By using TAIL-PCR we cloned approximately 2 kb length promoter sequence of AFS gene from‘Fuji’apple and‘Fertility’pear respectively and submitted them to GenBank（Accession number：KM676083 and KM676082）. The sequence alignment result showed that the homologous sequence of the two promoter is only 48.31%，is far less than the 97% similarity of their downstream coding region. cis-acting elements predicting analysis of the two promoters found that both promoters exist hormone response elements reponding to ethylene，abscisic acid，jasmonic acid，salicylic acid and/or stress response elements that response to low temperature，anaerobic environment and pathogen. Besides，three rhythmic expression elements and two inducer response elements are also found in both promoters. The expression pattern analysis found that some factors mentioned above have remarkable regulating effects on AFS gene transcription. Series deletions fragments of the AFS promoter from‘Fertility’pear were inserted into the upstream sequence of reporter gene in the expression vectors which were then used to transform the tobacco（NC89）. Analysis of the transcription activity of each fragment by GUS staining method indicated that the shortest 153 bp promoter fragment still maintain its transcription activity and two shortened promoters with length between 276 to 573 bp possess stronger transcription activity than other fragments. A more detailed etiology of superficial scald is supposed to be discovered when these cis-acting elements，especially the ethylene responsive element reported here shall have been thoroughly studied.

Key words: apple, pears, AFS, promoter, cis-acting elements, superficial scald