Differential expression of the auxin primary response gene MASSUGU2/IAA19during tropic responses of Arabidopsis hypocotyls

• DOI: 10.1111/j.1399-3054.2007.00898.x
• Publication Date: 2007-04-04T19:27:17Z
• Authors: Kyoko Saito; Masaaki K. Watahiki; Kotaro T. Yamamoto
• Keywords: Etiolation; Pericycle; Phototropism

We have examined the expression pattern of an auxin primary response gene, MSG2/IAA19 , during photo‐ and gravitropic responses hypocotyls using a transgenic Arabidopsis harboring promoter::GUS . The upper portion most etiolated showed uniform β‐glucuronidase (GUS) staining with strongest activity in pericycle. When were irradiated unilateral blue light, GUS on concave side was decreased, resulting differential stronger signal convex side. number differentially stained peaked at 24 h after onset phototropic stimuli, while hypocotyl curvature continued to increase for entire 36‐h experimental period. This result suggests that precedes responses. seedlings grown under dim white their displayed almost no activity. light‐grown also stimuli as hypocotyls, especially epidermis, outer cortex pericycle, although much weaker than observed hypocotyls. Similar but less obvious obtained Considering recent finding Aux/IAA proteins are immediate targets F box receptors, is likely act one master genes tropic