Comparison of two CBL genes on stress tolerance functions from Pyrus betulaefolia
[Objective] To investigated the molecular mechanism of pear calcineurin B-like protein (CBL)genes participating in the stress resistance progress preliminarily,two cDNAs designed as PbCBL1 and PbCBL7 were isolated from Pyrus betulaefolia Bunge and the sequence characteristics were analyzed.Furthermore,expression patterns and tolerance functions of the Escherichia coli cells conferred above genes were studied respectively.[Method] The open-reading frame (ORF) of cDNA and DNA sequences were isolated by EST sequence splice,RT-PCR and PCR techniques step by step.Bioinformatics methods were employed in the analysis of nucleotide sequences and their deduced protein structure.Semi-quantitative RT-PCR was used to reveal the expression modes of above genes via cross-introns primers and prokaryotic expression was applied in the research of stress tolerance of E.coli cells mediated by above genes apart.[Result] The cDNAs of PbCBL1 and PbCBL7 were 642 bp and 639 bp in length,respectively,and encoded 213 and 212 amino acids.The DNAs of PbCBL1 and PbCBL7 were 2 969 and 1 788 bp in length,separately,and both consisted of 8 exons and 7 introns.The deduced protein of either PbCBL1 or PbCBL7 contained four EF-hand structure domains and one calcineurin A subunit binding site,which was the hallmark of the CBLs of plants.The mRNA abundance of either of these genes was induced in leaves and roots by the stress of salt,drought,osmotic and ABA dramatically.Especially what deserves to be mentioned is the transcription level of PbCBL1 increased most visible in leaves in comparison with normal condition.The tolerance of E.coli BL21 (DE3)cells conferred PbCBL1 or PbCBL7 was enhanced under either salt stress or osmotic stress compared to the control cells.It is worth nothing that the stress tolerance ability of E.coli mediated by PbCBL1 is stronger than that of PbCBL7.[Conclusion] The results of our experiments show that both these two genes belong to the CBL gene family of P.betulaefolia and they may play important roles in the regulatory mechanism of abiotic stress.
Pyrus betulaefolia BungeCalcineurin B-like protein geneSequence featuresExpression characteristicsFunction comparison
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