Study of expression pattern analysis of BI-85 gene in tolerant and sensitive bread wheat cultivars and wild relative Aegilops crassa under salt stress

This study was carried out to identify new salt induced genes from wheat involved in salt stress tolerance using EST analysis and study the role of gene encoding BAX Inhibitor 1-like protein (BI-85) in response to salt stress. Using EST analysis, it is also cleared that BI-85 is one of the salt induced genes whose expression increased under salt stress condition. Hence, this gene was selected to determine its expression pattern in response to salinity stress in tolerant (Arg) and sensitive (Alamout) genotypes of wheat and its wild relative, Aegilops crassa (DD). Gene expression analysis at 0, 12 hours and 3 weeks after salt treatment using Real-time PCR revealed that the expression of BI_85 gene under salt stress in the root was markedly greater in Aegilops crassa compared with salt-tolerant and salt-sensitive cultivated genotypes although its expression was not significantly different between the three genotypes under unstressed conditions. Twelve hours after salt treatment, in Aegilops crassa the expression of BI-85 significantly increased in comparison with before treatment and its expression level was dramatically decreased after 3 weeks in these genotypes while the expression level of this gene was not different before and after salt treatment in cultivated genotypes. It looks there are some signal transduction pathways only in tolerant genotypes that increased salt tolerance in these genotypes and the product of BI-85 gene plays a critical role in these pathways and the protein encoded by this gene may contribute to a negative feedback regulation of BI-85 expression.