苹果光敏色素作用因子基因PIF 的克隆和分析

 以短枝型苹果（Malus domestica Borkh.）为试材，采用RT-PCR结合RACE技术，克隆获得一个光敏色素作用因子（PIF）基因，命名为MdPIF。该基因编码区共2 142 bp，推测其编码713个氨基酸。氨基酸序列分析显示，在其C端具有保守氨基酸结构域bHLH，N端具有光敏色素结合域APB，与其它植物光敏色素结合因子有很高的同源性。实时荧光定量PCR分析表明，在花后20 ~ 110 d，MdPIF在短枝型和非短枝型苹果枝条均能表达，同一生长时期，短枝型苹果枝条的表达量显著低于非短枝型，说明苹果短枝性状可能与MdPIF的差异表达有关。MdPIF在叶片、枝条、花瓣、果实和芽中均能表达，在不同器官中的表达量存在明显差异，在枝条中相对表达量最高，推测其可能主要调控苹果枝条的伸长。

Clone and Expression Analyzing of Phytochrome-interacting Factor Gene PIF of Spur Type Apple

A phytochrome-interacting factor(PIF)gene was isolate from the spur type apple(Malus domestica Borkh.)by using RT-PCR and RACE method,the gene was named MdPIF,containing an open reading frame(2 142 bp)and encoding a protein of 713 amino acid. Sequence analysis indicated that MdPIF shared highly homology with bHLH family protein and the APB domain of phytochrome- interacting. The real-time quantitative PCR analysis showed that MdPIF gene expressed in stem of spur type apple trees during the 20–110 days after flowering. In the same development stage,the MdPIF was lower expression in spur type apple stem than in non-spur type apple. The MdPIF gene was expressed in leaf,stem,flower,fruit and bud of the spur type apple. However,the expression of the gene was different. The relative expression level of MdPIF gene was up to the maximum value in the stem. The research results suggested that the MdPIF gene play an important role during the stem developing of apple.