Transgenic Analysis Reveals 5′ Abbreviated OsRGLP2 Promoter(s) as Responsive to Abiotic Stresses

Germins and germin-like proteins are ubiquitous, expressed at various developmental stages and in response to various abiotic and biotic stresses. In this study, to functionally validate the OsRGLP2 promoter, 5′ deletion analysis of the promoter sequences was performed and the deletion fragments fused with the β-glucuronidase (GUS) and green fluorescent protein reporter genes were used for transient expression in tobacco as well as for generating stable transgenic Arabidopsis plants. Very high level of GUS activity was observed in agroinfiltrated tobacco leaves by the construct carrying the P-1063 and P-565 when subjected to abiotic stresses. Histochemical analysis of transgenic Arabidopsis plants revealed expression of reporter gene in root, leaf and stem sections of plants harboring P-1063 and P-565. Real-time qPCR analysis of transiently expressed tobacco leaves and transgenic Arabidopsis plants subjected to several abiotic stresses supported histochemical data and showed that P-565 responded to all the stresses to which the full-length promoter was responsive. The data suggest that P-565 may be a good alternative to full-length promoter region that harbors the necessary cis-elements in providing stable and high level of expression in response to wound, salt and temperature stresses.