Isolation of pigeon pea (<i style="">Cajanus cajan </i>L.) legumin gene promoter and identification of conserved regulatory elements using tools of bioinformatics

Abstract

A seed specific legumin gene promoter from pigeon pea was isolated by PCR amplification. Database assisted sequence analysis of this promoter revealed several putative <i style="">cis</i>-acting regulatory elements. Comparative analysis of 15 seed-specific legumin gene promoters from six species, <i style="">viz. Cajanus cajan, Cicer arietinum, Pisum sativum, Glycine max, Vicia faba and Arachis hypogaea</i>, revealed several conserved motifs in promoter sequences; maximum conservation was observed upstream to transcription start site. Most of the conserved motifs have known transcription factor binding sites. One unknown conserved motif of seven base pair (AG/TGTGTA) was found 19 bp upstream to legumin box, putatively named as L-19. Study of nucleosome formation potential showed that putative linker DNA is more prone to mutations as compared to DNA involved in nucleosome formation. A chimeric construct was made with pigeonpea legumin promoter and β-glucuronidase (<i style="">GUS</i>)<i style=""> </i>gene. Analysis of <i style="">GUS </i>expression at different developmental stages of transgenic tobacco plant’s parts revealed that the reporter gene was expressed at a high level only in mature seeds, specifically in embryo, endosperm and in cotyledonary leaves of developing seedling. These data showed that <i style="">GUS </i>gene transcription was regulated in a tissue specific and temporally regulated manner.