SCL28 modulates organ growth in Arabidopsis by controlling mitotic cell cycle exit, endoreplication and cell expansion dynamics

BARRERA, VIRGINIA; GOLDY, CAMILA; LÓPEZ ALSINA, MERCEDES; TAYLOR, ISAIAH; BUCHENSKY, CELESTE; VENA, RODRIGO; BENFEY, PHILIP N.; DE VEYLDER, LIEVEN; RODRIGUEZ VIRASORO, RAMIRO ESTEBAN

Mendoza

Congreso; 58th Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology; 2022

SAIB

Plant organ growth initiates with proliferating cells generated by the mitotic cell cycle (MCC). Then, cellsenter an expansion and differentiation program. During this later stage, plant cells often switch to analternative cell cycle named endoreplication (ER), in which cells replicate their DNA without progressingthrough mitosis nor cytokinesis, generating somatic polyploidy. The transition from MCC to ER involvesregulatory 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´veshown that the Arabidopsis thaliana SCL28 transcription factor promotes mitotic G2/M progression. Toextend this characterization, we performed a transcriptome analysis of scl28-3, a mutant in this gene.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 membersof SIAMESE/SIAMESE-RELATED (SIM/SMR ) family in the mutant. These proteins have been reported to triggerthe transition from the MCC to ER by its association with specific CDKs. In this work we characterize therole of SCL28 in both roots and leaves development. We found that this transcription factor is involved inthe switch from the proliferation to the cell expansion phases, promoting ER and regulating cell wall andcytoskeleton assembly genes.