Isolation and characterization of a green tissue-specific promoter from pigeonpea [<i>Cajanus cajan </i>(L.) Millsp.]

Abstract

Expression of <i>rbcS </i>genes encoding small subunit of rubisco, most abundant protein in green tissue, is regulated by at least three parameters-tissue type, light conditions and stage of development. One of the green tissue-specific promoters of <i>rbcS </i>gene family was isolated from pigeonpea by PCR. Expression of <i>uidA </i>gene encoding β-glucuronidase in the transgenic tobacco plants under the control of pigeonpea <i>rbcS </i>promoter, clearly showed that this promoter was as strong as pea <i>rbcS3A</i> promoter characterized earlier. Study of the sequence similarity with pea <i>rbcS3A </i>promoter, especially the region (boxes I and III) that is required for <i>rbcS3A </i>expression, showed more than 50% divergence. In contrast, pigeonpea promoter sequence isolated in the present study was more similar to that of spinach and rice <i>rbcS </i>promoters.