矮牵牛B-box型锌指蛋白基因PhBBX8的克隆与表达分析

利用矮牵牛（Petunia hybrida）基因表达谱芯片筛选出应答低温胁迫的相关基因，从中发现1个B-box型锌指蛋白基因PhBBX8。通过RT-PCR克隆得到该基因的编码区序列（CDS），为1 242 bp，预测其编码氨基酸413 aa，N端含有2个B-box盒，C端含有1个CCT结构域。系统进化树分析发现，PhBBX8与拟南芥AtBBX8等聚类为一支。利用半定量RT-PCR检测其在根、茎、叶和花中的表达特性，结果表明该基因在花中表达量较高，其次为根，而在茎和叶中表达较弱；利用实时定量PCR检测了在低温、干旱、ABA、MeJA、高盐和高渗胁迫处理下矮牵牛叶片中PhBBX8的诱导表达情况，结果表明，PhBBX8表现出不同程度的上调，其中除干旱胁迫外，其他胁迫下上调倍数都较高，初步推测该基因与矮牵牛应答低温等非生物逆境相关。

Cloning and Expression Analysis of a B-box-type Zinc-finger Protein Gene PhBBX8 in Petunia hybrida

Gene expression microarray of petunia was applied to select cold responsive gene，from which a B-box-type zinc-finger protein gene PhBBX8 was discovered. The full length of the coding region of PhBBX8 amplified by RT-PCR was 1 242 bp，and the product of PhBBX8 gene was predicted to consist of 413 amino acid residuals containing two B-box domains at the N-terminal and one CCT domain at the C-terminal. The phylogenetic tree analyses showed that PhBBX8 was clustered in the same branch with AtBBX8 in Arabidopsis. By semi-quantitative RT-PCR，PhBBX8 was found to express differentially in all the tissues detected，including root，stem，leaf and flower. Stress induced expression analysis by real-time quantitative PCR showed that the expression of PhBBX8 could be induced not only by cold，but also by drought，ABA，MeJA，salt and hypertonic stresses in different degrees，suggesting PhBBX8 gene was associated with the responses of cold and other abiotic stresses.