Activity of Arabidopsis Rubisco small subunit promoter in various tissues of chickpea.

The activity of a green tissue-specific promoter of the Rubisco small subunit gene from  () was studied using transgenic chickpea lines. We generated transgenic chickpea lines expressing an  promoter-driven  gene through mediated transformation method. Lines with  expressed the gene in all green tissues at high levels (> 90 ng/mg of fresh weight tissue) compared to lines generated using  (< 10 ng/mg FW). We used vertical cross sections of various tissues of homozygous progeny using microtome for immunolocalization. The immunolocalization showed the expression of the  gene in the green mesophyll cells of the leaves of both  and CaMV35 chickpea lines. Moreover, the accumulation of regulated Cry2Aa protein was also observed in vascular tissues, including enucleate sieve elements and their companion cells. However, no expression was observed in the roots of  lines. In the case of  lines, the transgene expression was observed in all the tissues. Since our data indicated that the  promoter is active in non-green tissues such as vascular bundles. Therefore, we validated this by RT-PCR. We found Cry2Aa RNA transcripts in leaves, stems without epidermis (for vascular tissues), and roots with and without epidermis. Thus, the  promoter is active in all above-ground tissues of the chickpea plant.