The effect of indole-3-carbinol on PIN1 and PIN2 in Arabidopsis roots

Abstract

The phytochemical indole-3-carbinol is produced in Cruciferous plants upon tissue rapture and deters herbivores. We recently showed that indole-3-carbinol modulates auxin signaling in root tips. Here we present transcript profiling experiments which further reveal the influence of indole-3-carbinol on auxin signaling in root tips, and also show that I3C affects auxin transporters. Brief treatment with indole-3-carbinol led to a reduction in the amount of PIN1 and to mislocalization of PIN2.

Keywords: Arabidopsis thaliana; auxin; glucosinolate; indole 3 carbinol.

Figure 1.

I3C treatment leads to misregulation of auxin responsive genes. Heat map of the expression of known auxin-responsive genes following treatment with 500μM I3C for one hour. RNA was extracted from root tips of 10-day-old seedlings and hybridized to Affymetrix ATH1 chips. A 2 fold cutoff was used. The list of auxin-responsive genes was extracted according to gene ontology in Agrigo [22].

Figure 2.

I3C treatment affects auxin transporters. (A) Seedlings expressing PIN1:GFP were grown on MS medium for 5 days, treated with 200 μM of I3C or with DMSO for 30 minutes, and imaged using confocal microscopy (Zeiss LSM780, with a 40x water objective). Heat-maps represent GFP density. GFP fluorescence was quantified using ImageJ software. (B) Seedlings expressing PIN2:GFP were grown on MS medium for 6 days, treated with 200 μM of I3C or with DMSO for 30 minutes, and imaged using confocal microscopy (Zeiss LSM780, with a 40x water objective). Cell walls were stained using 0.005mg/ml propidium iodide. co = cortex, ep = epidermis.