Studies on the tissue specific nature and stress inducible activation of the CHI-1 gene from banana

In the present study, the 5′-regulatory region of chalcone isomerase gene (MusaCHI-1) of banana was functionally analysed for its tissue specific, stress mediated and strong guard cell preferred activity. Expression of MusaCHI-1 was altered in leaves of banana plants exposed to various stress conditions and signalling molecules. Transgenic lines of tobacco harbouring PMusaCHI-1-GUS displays prominent GUS staining in vascular region and guard cells of leaves which corroborates with array of Dof1 binding cis-elements in PMusaCHI-1 region. Multiple cis-elements associated with various stress conditions were detected in PMusaCHI-1 which directly correlates with alteration of MusaCHI-1 transcript level in banana exposed to stress conditions. GUS staining of transgenic tobacco plants harbouring PMusaCHI-1-GUS and exposed to drought, salinity, and applications of methyl jasmonate and abscisic acid indicated activation of PMusaCHI-1 under these conditions while exposure of salicylic acid strongly suppresses GUS expression from PMusaCHI-1.