Cytokinin transporter azg2 modulates cell wall remodeling during lateral root emergence in Arabidopsis thaliana

Abstract

Tissue remodeling is essential for lateral root (LR) emergence. Many studies have focused on the role of auxin in this process but little is known about cytokinin (CK) relevance. AZG2 is an auxin regulated CK transporter, involved in negative regulation of LR development in Arabidopsis. AZG2 is expressed in a small group of cortical and epidermal cells (OLT) surrounding lateral root primordia (LRP), resembling some cell wall remodeling enzymes (CWREs) involved in lateral root emergence (LRE). Here, we study LRE and cell wall remodeling (CWR) in Arabidopsis roots of WT and azg2-1 genotypes through two independent experiments. LRP/LR index was calculated and values were 2,93 for azg2-1 and 3,48 for WT roots, confirming that AZG2 has a regulatory effect on LRE. Additionally, a lower propidium iodide fluorescence intensity was detected in the OLTs of azg2 seedlings compared to WT, suggesting an increased CWR activity in the mutant genotype. Taken together, these results indicate that CK transport mediated by AZG2 could modulate CWR during LRE. In order to get further insight, we are currently working on pCWRE:GUS:GFP/WT and pCWRE:GUS:GFP/azg2 reporter lines to study CK effect on the expression of two different CWREs.