黄瓜细胞分裂素合成关键酶IPT 基因家族序列特征及其表达分析

 为了分析黄瓜IPT家族基因，以及黄瓜IPT基因CsIPT与果实发育的关系，以黄瓜单性结实自交系‘EC1’和非单性结实自交系‘8419s-1’为试材，应用荧光定量PCR技术，在分析不同器官中CsIPT表达特征的基础上，寻找果实发育中的作用基因，进一步分析这些基因在果实发育过程中的表达特征。结果表明：8个黄瓜IPT基因（CsIPT1 ~ CsIPT8）核苷酸相似性在17.3% ~ 33.2%范围内，氨基酸长度在280 ~ 504 AA之间，具有共同的ATP/GTP结合功能域(A,G)-X₄-G-K-(S,T)]，CsIPT4氨基酸序列中包含有一个锌指基序（C-X₂-C-X_12,18-H-X₅-H）类似序列；黄瓜幼果中CsIPT3、CsIPT5、CsIPT7和CsIPT8表达水平较高；CsIPT1、CsIPT3、CsIPT4和CsIPT5的表达量在未发育的果实中有增加的趋势，CsIPT2和CsIPT8在未发育的果实中表达基本无变化，而在授粉后发育的果实中表达量很高，说明这两个基因可能与授粉后黄瓜果实发育调控有关。此外，CsIPT2在天然单性结实材料‘EC1’果实发育早期表达较高，推测其在黄瓜单性结实果实发育中发挥着重要作用。

Identification and Characterization of CsIPT Genes in Cucumber

To identify IPT family genes in cucumber（Cucumis sativus L.）and investigate the relationship between cucumber fruit development and CsIPT，parthenocarpic line‘EC1’and non-parthenocarpic line‘8419s-1’were used for real-time RT-PCR analyses. Based on the expression patterns of CsIPT in different organs，functional genes involved in fruit development were identified and further analyzed by their expression patterns during fruit development. The results indicated that similarity of eight CsIPT genes were in the range of 17.3%–33.2%，length of amino acids were 280–504 AA. CsIPTs had a common ATP/GTP binding domain of the(A,G)-X₄-G-K-(S,T)]. CsIPT4 contained putative a zinc finger-like motif（C-X₂-C-X_12,18-H-X₅-H）. CsIPT3，CsIPT5，CsIPT7 and CsIPT8 had higher expression in the early cucumber fruit. In the undeveloped fruit CsIPT1，CsIPT3，CsIPT4 and CsIPT5 showed an significant increasing trend. CsIPT2 and CsIPT8 were related to fruit development after pollination，at the same time the expression of CsIPT2 was higher in the early fruit development of‘EC1’. Therefore，it was speculated that CsIPT2 may participated in the regulation of fruit development in cucumber parthenocarpic line.