Drought induction of Arabidopsis 9-cis-epoxycarotenoid dioxygenase occurs in vascular parenchyma cells.
The regulation of abscisic acid (ABA) biosynthesis is essential for plant responses to drought stress. In this study, we examined the tissue-specific localization of ABA biosynthetic enzymes in turgid and dehydrated Arabidopsis (Arabidopsis thaliana) plants using specific antibodies against 9-cis-epoxycarotenoid dioxygenase 3 (AtNCED3), AtABA2, and Arabidopsis aldehyde oxidase 3 (AAO3). Immunohistochemical analysis revealed that in turgid plants, AtABA2 and AAO3 proteins were localized in vascular parenchyma cells most abundantly at the boundary between xylem and phloem bundles, but the AtNCED3 protein was undetectable in these tissues. In water-stressed plants, AtNCED3 was detected exclusively in the vascular parenchyma cells together with AtABA2 and AAO3. In situ hybridization using the antisense probe for AtNCED3 showed that the drought-induced expression of AtNCED3 was also restricted to the vascular tissues. Expression analysis of laser-microdissected cells revealed that, among nine drought-inducible genes examined, the early induction of most genes was spatially restricted to vascular cells at 1 h and then some spread to mesophyll cells at 3 h. The spatial constraint of AtNCED3 expression in vascular tissues provides a novel insight into plant systemic response to drought stresses.
Department of Biological Sciences, Tokyo Metropolitan University, Hachiouji, Tokyo 192-0397, Japan.
Akira
A
Endo
Yoshiaki
Y
Sawada
Hirokazu
H
Takahashi
Masanori
M
Okamoto
Keiichi
K
Ikegami
Hanae
H
Koiwai
Mitsunori
M
Seo
Tomonobu
T
Toyomasu
Wataru
W
Mitsuhashi
Kazuo
K
Shinozaki
Mikio
M
Nakazono
Yuji
Y
Kamiya
Tomokazu
T
Koshiba
Eiji
E
Nambara
D000040:Abscisic Acid / Q000096:biosynthesis; D000429:Alcohol Oxidoreductases / Q000032:analysis / Q000378:metabolism; D042931:Aldehyde Oxidase / Q000032:analysis / Q000378:metabolism; D000906:Antibodies / Q000737:chemistry; D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000032:analysis / Q000378:metabolism; D003681:Dehydration; D049308:Dioxygenases; D015870:Gene Expression; D010105:Oxygenases / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D010940:Plant Proteins; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D015398:Signal Transduction
D000906:Antibodies; D029681:Arabidopsis Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D000040:Abscisic Acid; C469255:ABA2 protein, Arabidopsis; D000429:Alcohol Oxidoreductases; D010105:Oxygenases; D049308:Dioxygenases; C109043:9-cis-epoxy-carotenoid dioxygenase; C470342:AAO3 protein, Arabidopsis; D042931:Aldehyde Oxidase