Effects of locally targeted heavy-ion and laser microbeam on root hydrotropism in Arabidopsis thaliana.
Classical studies on root hydrotropism have hypothesized the importance of columella cells as well as the de novo gene expression, such as auxin-inducible gene, at the elongation zone in hydrotropism; however, there has been no confirmation that columella cells or auxin-mediated signaling in the elongation zone are necessary for hydrotropism. We examined the role of root cap and elongation zone cells in root hydrotropism using heavy-ion and laser microbeam. Heavy-ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporarily suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy-ion broad-beam irradiation suppressed de novo expression of INDOLE ACETIC ACID 5 gene, but not MIZU-KUSSEI1 gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that de novo gene expression might be required for hydrotropism in the elongation zone, but not in columella cells.
Miyazawa
Yutaka
Y
Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, Japan. miyazawa@ige.tohoku.ac.jp
Sakashita
Tetsuya
T
Funayama
Tomoo
T
Hamada
Nobuyuki
N
Negishi
Hiroshi
H
Kobayashi
Akie
A
Kaneyasu
Tomoko
T
Ooba
Atsushi
A
Morohashi
Keita
K
Kakizaki
Takehiko
T
Wada
Seiichi
S
Kobayashi
Yasuhiko
Y
Fujii
Nobuharu
N
Takahashi
Hideyuki
H
D017360:Arabidopsis / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D020450:Heavy Ions; D007834:Lasers; D018517:Plant Roots / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects*; D010944:Plants; D011829:Radiation Dosage; D018523:Tropism / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects*; D014867:Water / Q000494:pharmacology*
D014867:Water