RF2a, a bZIP transcriptional activator of the phloem‐specific rice tungro bacilliform virus promoter, functions in vascular development

摘要: Rice tungro bacilliform virus (RTBV) replicates only in phloem cells infected rice plants and its promoter drives strong phloem-specific reporter gene expression transgenic plants. We isolated a cDNA encoding basic leucine zipper (bZIP) protein, RF2a, which binds to the Box II cis element that is important for from promoter. stimulates II-dependent transcription homologous vitro system, accumulates nuclei of certain other cell types shoots, but found at very low levels roots. Transgenic antisense RF2a accumulation was suppressed had normal roots stunted, twisted leaves with small, disorganized vascular bundles, an enlarged sclerenchyma large air spaces. propose RTBV exploits host factor critical leaf tissue differentiation development expression.