The Anaphase Promoting Complex/Cyclosome Subunit 11 and Its Role in Organ Size and Plant Development

Abstract

The anaphase promoting complex/cyclosome (APC/C), a member of the E3 ubiquitin ligase family, plays an important role in recognizing the substrates to be ubiquitylated. Progression of anaphase, and therefore, of the cell cycle, is coordinated through cyclin degradation cycles dependent on proteolysis triggered by APC/C. The APC/C activity depends on the formation of a pocket comprising the catalytic subunits, APC2, APC11, and APC10. Among these, the role of APC11 outside the cell division cycle is poorly understood. Therefore, the goal of this work was to analyze the function of APC11 during plant development by characterizing <i>apc11</i> knock-down mutant lines. Accordingly, we observed decreased <i>apc11</i> expression in the mutant lines, followed by a reduction in meristem root size based on the cortical cell length, and an overall size diminishment throughout the development. Additionally, crosses of <i>apc11-1</i> and <i>amiR-apc11</i> with plants carrying a WUSCHEL-RELATED HOMEOBOX5 (WOX5) fluorescent marker showed a weakening of the green fluorescent protein-positive cells in the Quiescent Center. Moreover, plants with <i>apc11-1</i> show a decreased leaf area, together with a decrease in the cell area when the shoot development was observed by kinematics analysis. Finally, we observed a decreased APC/C activity in the root and shoot meristems in crosses of pCYCB1;1:D-box-GUS with <i>apc11-1</i> plants. Our results indicate that APC11 is important in the early stages of development, mediating meristematic architecture through APC/C activity affecting the overall plant growth.