Cucumber BAX inhibitor-1, a conserved cell death suppressor and a negative programmed cell death regulator under cold stress

• Published in: Biologia plantarum Vol. 57; no. 4; pp. 684 - 690
• Main Authors: Chen, X. H, Yu, H, Deng, H. J, Chen, J. X, Mi, H. B, Mao, L. C
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 01.12.2013; Springer Netherlands; Institute of Experimental Botany of the Czech Academy of Sciences
• Subjects: amino acids; apoptosis; Arabidopsis thaliana; Biomedical and Life Sciences; cold stress; complementary DNA; cucumbers; cucumis sativus; genes; Life Sciences; open reading frames; Original Papers; Plant Sciences; rt-pcr; RT-PCR
• ISSN: 0006-3134; 1573-8264
• DOI: 10.1007/s10535-013-0347-8

Programmed cell death (PCD) is a genetically controlled and conserved process in eukaryotes during development as well as in response to pathogens and other stresses. BAX inhibitor-1 (BI-1) has been implicated as an anti-PCD factor which is highly conserved in plants. Sequence of putative cucumber BI-1 protein exhibited 77.7 % identity and 91.2 % positive value with the homologue Blast BI-1 protein of Arabidopsis thaliana (AtBI-1). This highly homologous protein to the AtBI-1 protein was named CsBI-1. This protein contains an open reading frame (ORF) of 250 amino acids with a BAX inhibitor domain and five transmembrane regions conserved among members of the BI-1 family. Primers designed by the cDNA of CsBI-1gene were used for further sequencing. Cell death in cold-stored cucumber developed concomitantly with increased expression of the CsBI-1 gene and reached maximum at day 6. However, cell death accelerated significantly after 9 d when sharp decrease of the CsBI-1 expression occurred. After warming to 20 °C, expression of the CsBI-1 gene was the highest at day 3, decreased afterwards, and the lowest expression was detected at day 9 when PCD obviously appeared. The overall results indicate that CsBI-1 is cucumber homologue of Arabidopsis thaliana AtBI-1 gene. CsBI-1 is a conserved cell death suppressor induced by cold stress and a negative regulator of PCD.