The MsPRP2 promoter enables strong heterologous gene expression in a root-specific manner and is enhanced by overexpression of Alfin 1.

Promoter specificity and efficiency of utilization are essential for endogenous and transgene expression. Selective root expression remains to be defined in terms of both promoter elements and transcription factors that provide high levels of ubiquitous expression. We characterized expression from the MsPRP2 promoter with the green fluorescent protein (GFP) reporter transgene in alfalfa (Medicago sativa) and found that a promoter fragment (+1 to -652 bp) retained the root and callus specificity of the endogenous MsPRP2 gene and hence this promoter fragment contains elements necessary for root-specific expression.