SCL28 PROMOTES ENDOREPLICATION AND CELL EXPANSION IN ARABIDOPSIS BY ACTIVATING A GROUP OF SIAMESE-RELATED CYCLIN-DEPENDENT KINASE INHIBITORS.

BARRERA, VIRGINIA LIS; GOLDY, CAMILA; TAYLOR ISAIAH; BUCHENSKY CELESTE ; VENA RODRIGO ; BENFEY PHILIP N. ; DE VEYLDER LIEVEN ; RODRIGUEZ RAMIRO E.

Mendoza

Congreso; LVIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2022

SAIB

Plant organ growth initiates with proliferating cells generated by the mitotic cell cycle (MCC). Then, cells enter an expansion and differentiation program. During this later stage, plant cells often switch to an alternative cell cycle named endoreplication (ER), in which cells replicate their DNA without progressing through mitosis nor cytokinesis, generating somatic polyploidy. The transition from MCC to ER involves regulatory mechanisms that specifically inhibit mitotic cyclin/cyclin-dependent kinase (CDKs) complexes causing cells to oscillate between S and G1 without engaging into mitosis. Previously, we´ve shown that the Arabidopsis thaliana SCL28 transcription factor promotes mitotic G2/M progression. To extend this characterization we performed a transcriptome analysis of scl28-3 a mutant in this. Among the differentially expressed genes we found genes related to cell elongation and differentiation, including cell wall and cytoskeleton assembling related genes. Also, we found downregulated 6 members of SIAMESE/SIAMESE-RELATED (SIM/SMR) family in the mutant. These proteins have been reported to trigger the transition from the MCC to ER by its association with specific CDKs. In this work we characterize the role of SCL28 in both roots and leaves development. We found that this transcription factor is involved in switch from the proliferation to the cell expansion phases, promoting ER and regulating cell wall and cytoskeleton assembly genes.