The researchers characterize the function of the transcription factor SCARECROW-LIKE28 in the regulation of leaf and root development

Members of the RNA Biology and Cellular Programming research group at IBR have published a new contribution to understanding plant development in the journal New Phytologist.

The goal was to understand how cellular processes that lead to the formation of plant organs, such as leaves and roots, are regulated. It’s been noticed that plants tend to have a particular termination at the tips of their stems where new leaves are formed. In this region, the cells belong to a structure called the Meristem, where they are actively multiplying and differentiating to form new structures. Cell proliferation occurs through mitosis, a cycle in which a cell replicates all the DNA in its nucleus and then divides into two identical daughter cells. After exiting consecutive mitotic cycles, the cells follow differentiation and expansion programs that are finely regulated by the precise expression or silencing of genes.

Frequently, after the mitotic cycles, the cells undergo an alternate cycle called “endoreplication” because, unlike mitosis, the DNA is replicated but the cell does not divide. This creates cells that increase the amount of DNA in their nuclei. Although the function of this alternate cycle is not yet certain, its importance is deduced as the existence of these cells with more DNA is subject to specific temporal and spatial control.

Ramiro Rodríguez and members of the research group, along with research support staff from the IBR Microscopy Unit, studied gene expression in meristem cells of the stems and roots of the Arabidopsis thaliana plant. They found that a protein, acting as a gene expression regulator (a transcription factor) called SCL28, promoted organ growth by modulating the dynamics of cell expansion in roots and leaves.

They were able to demonstrate that this regulation is exerted through the control of the expression of a family of inhibitors that determine the exit of cells from the mitotic cell cycle and their entry into endoreplication. Their results suggest that SCL28 controls not only proliferation but also cell expansion and differentiation, promoting the exit from the mitotic cell cycle and the entry into endoreplication, thus modulating aspects of biogenesis, assembly, and remodeling of fundamental cellular structures such as the cell wall or cytoskeleton. Thus, SCL28, present not only in the model plant used in research but also in species of agricultural interest, regulates the magnitude and speed of plant organ growth, an essential parameter for defining crop yield.

Congratulations to the authors Camila Goldy, Virginia Barrera, Celeste Buchensky, and authors Isaiah Taylor, Rodrigo Vena, Philip N. Benfey, Lieven De Veylder, and Ramiro Rodríguez on this research work!