# The REPLUMLESS Transcription Factor Controls the Expression of the RECEPTOR-LIKE CYTOPLASMIC KINASE VI_A2 Gene Involved in Shoot and Fruit Patterning of Arabidopsis thaliana

## TL;DR

This study shows how a transcription factor controls a kinase gene involved in plant growth and development in Arabidopsis.

## Contribution

The study identifies RPL as a regulator of RLCKVI_A2 and explores their roles in plant patterning.

## Key findings

- The RLCKVI_A2 gene is downregulated in the rpl-4 mutant, showing RPL's regulatory role.
- Both RPL and RLCKVI_A2 affect stem growth, vascular tissue organization, and phyllotaxis.
- Constitutive expression of RLCKVI_A2 alters vascular differentiation and stem growth.

## Abstract

The promoter of the RECEPTOR-LIKE CYTOPLASMIC KINASE VI_A2 (RLCK VI_A2) gene contains nine binding sites for the REPLUMLESS (RPL) transcription factor. In agreement, the expression of the kinase gene was strongly downregulated in the rpl-4 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 RLCKVI_A2 gene from the constitutive 35S promoter could not complement the rpl-4 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 RLVKVI_A2 genes, it highlights the significance of the proper developmental regulation of the RLCKVI_A2 promoter for balanced stem development.