Abstract
Isolated mesophyll cells of zinnia (Zinnia elegans) can be induced to trans-differentiate into tracheary elements (TEs) in vitro. We developed an electroporation-based gene transfer method, using which we investigated an effect of the introduction of double-stranded RNAs (dsRNAs) corresponding to TE differentiation-specific genes with unknown functions into zinnia cells on a rate of TE differentiation. As a result, it was revealed that dsRNAs for two similar genes, ZeTED6 and ZeTED7, showed strong inhibitory effects. In the zinnia system, the rate of TEs was apparently promoted by co-overexpressing of ZeTED6 and ZeTED7 genes. In addition, we found that the Arabidopsis homologues, AtTED6 and AtTED7, showed TE differentiation-specific expression. Analysis in transgenic Arabidopsis plants revealed that RNA interference for AtTED7 resulted in lethal phenotype during seedling development. Based on the results, we would discuss the involvement of these genes in TE differentiation.
