Poster: Root Biology

Abs # 532: Contrary effects of dark adaptation and far-red light illumination on gene regulation in roots of Arabidopsis thaliana

Presenter:	Sato-Nara, Kumi , kumisn@postman.riken.go.jp
Authors	Sato-Nara, Kumi  (A)   Yamashita, Hizuru  (A)   Sun, Qiang  (A)   Seki, Motoaki  (B) (C)  Shinozaki, Kazuo  (B) (C)  Suzuki, Hitoshi  (A) (D)
Affiliations:	(A): Photodynamics Research Center, RIKEN (The Institute of Physical and Chemical Research), Japan (B): Genomic Sciences Center, RIKEN, Japan (C): Tsukuba Institute, RIKEN, Japan (D): Faculty of Science and Engineering, Ishinomaki-Senshu University, Japan

Roots in the soil are illuminated by far-red (FR) light passed through plant tissues and soil in the daytime, and are in complete darkness in the nighttime. To understand whether gene expression of roots is affected by a dark-FR light cycle, we analyzed gene expression profiles for dark adapted versus light-grown plants and for far-red light illuminated versus dark-adapted plants using the RIKEN Arabidopsis full-length cDNA microarray (containing ca. 7000 independent, full-length cDNA groups). In roots of Arabidopsis thaliana (Ler ecotype), transcripts of 37 genes increased after dark adaptation. Six of these belong to the Major Intrinsic Protein (MIP) superfamily of transmembrane channel proteins. RNA gel blot analysis on three genes of the MIP family showed that the transcripts increased with dark adaptation and slightly decreased under FR light illumination. Both cDNA microarray analysis and RNA gel blot analysis indicated that there are few genes highly induced by FR light in dark-adapted roots. The results suggest that the action of FR light on the expression of several genes in roots is contrary to that of dark adaptation.