The REPLUMLESS Transcription Factor Controls the Expression of the Gene Involved in Shoot and Fruit Patterning of .

The promoter of the () gene contains nine binding sites for the REPLUMLESS (RPL) transcription factor. In agreement, the expression of the kinase gene was strongly downregulated in the mutant. Comparing phenotypes of loss-of-function mutants, it was revealed that both genes are involved in stem growth, phyllotaxis, organization of the vascular tissues, and the replum, highlighting potential functional interactions. The expression of the gene from the constitutive 35S promoter could not complement the phenotypes but exhibited a dominant positive effect on stem growth and affected vascular differentiation and organization. The results also indicated that the number of vascular bundles is regulated independently from stem thickness. Although our study cannot demonstrate a direct link between the RPL and genes, it highlights the significance of the proper developmental regulation of the promoter for balanced stem development.