FtsH (Filamentation Temperature-Sensitive H)是一种ATP和Zn2+依赖型金属蛋白酶，广泛存在于原核生物和真核生物中，在真核生物中是多基因家族。FtsH具有ATP酶活性、蛋白水解活性和分子伴侣活性，参与多种胁迫反应。从抗旱马铃薯（Solanum tuberosum）二倍体品系H145中分离得到cDNA-AFLP差异片段,利用RACE技术克隆了SoFtsH cDNA全长序列, 并对其进行分析。结果表明, 该序列包含完整的开放阅读框，长为723 bp, 编码129个氨基酸。SoFtsH具有2个铁氧化还原蛋白结合位点，并存在信号肽序列、跨膜区域和Zn2+结合域。SoFtsH基因序列与GenBank数据库中的其他FtsH基因进行同源序列比对, 并构建系统进化树, 发现该基因与番茄、烟草、拟南芥等高等植物FtsH基因同源性达90%以上。半定量RT-PCR和Northern Blot杂交结果表明SoFtsH基因在干旱胁迫下叶片和根系里的表达量明显增加, 且在抗旱品系H145与干旱敏感品系H214中表达模式不同。说明SoFtsH基因在马铃薯抗旱中起作用。
Filamentation temperature-sensitive H (FtsH) is an ATP dependent metalloprotease and chaperone identified in many prokaryotes and eukaryotes; its homologs have been identified in many plants. FtsH belongs to a larger family of proteins collectively known as the AAA proteins (ATPases associated with diverse cellular activities). Function studies have revealed an important role for FtsH in stress responses. On the basis of one cDNA-AFLP differential fragment isolated from induced mRNA under drought in the potato （Solanum tuberosum L.） genotype H145 that is diploid with drought tolerance, the full length cDNA of a putative FtsH gene, SoFtsH gene was cloned by rapid amplification of cDNA ends (RACE). The gene consists of 723 bp encoding a predicted protein of 129 amino acids. Sequence analysis revealed that it has two 2Fe-2S ferredoxins, iron-sulfur binding regions. The putative signal-peptide, transmembane regions and the Zn2+ binding domain, characteristic of FtsH metalloproteases family, were found in the SoFtsH protein. Alignment and phylogenetic analysis of the amino acid sequence deduced from the fragment and the FtsH sequences of other plants retrieved from GenBank were performed with ClustalX program, which showed that SoFtsH shares high identity (>90%) with FtsH reported in tomato, tobacco and Arabidopsis etc. Transcription level of of SoFtsH was investigated by semi-quantitative RT-PCR and Northern blot, using actin gene as a control. The result showed that the transcript of SoFtsH was significantly enhanced under drought. The different profiles of transcript of SoFtsH gene were detected under continuous drought between drought tolerant H145 and drought sensitive H214 that is susceptive to drought. The results suggest that SoFtsH gene is closely related with the drought tolerance in potato.
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