Transient expression of AtNCED3 and AAO3 genes in guard cells causes stomatal closure in Vicia faba.
Abscisic acid (ABA) regulates stomatal closure in response to water loss. Here, we examined the competence of guard cells to synthesize ABA, using two Arabidopsis ABA biosynthetic enzymes. 35S pro::AtNCED3-GFP and AAO3-GFP were introduced into guard cells of broad bean leaves. AtNCED3-GFP expression was detected at the chloroplasts, whereas green fluorescent protein (GFP) and AAO3-GFP were in the cytosol. The stomatal aperture was decreased in AtNCED3-GFP- and AAO3-GFP-transformed guard cells. This indicated that ABA biosynthesis is stimulated by heterologous expression of AtNCED3 and Arabidopsis aldehyde oxidase 3 (AAO3) proteins, which both seem to be regulatory enzymes for ABA biosynthesis in these cells. Furthermore, stomatal closure by the expression of AtNCED3 and AAO3 suggested that the substrates of the enzymes are present and native ABA-biosynthesis enzymes are active in guard cells.
Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan.
Vanessa
V
Melhorn
Kunimi
K
Matsumi
Hanae
H
Koiwai
Keiichi
K
Ikegami
Masanori
M
Okamoto
Eiji
E
Nambara
Florian
F
Bittner
Tomokazu
T
Koshiba
D000040:Abscisic Acid / Q000096:biosynthesis; D042931:Aldehyde Oxidase / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D049308:Dioxygenases; D018506:Gene Expression Regulation, Plant; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins; D054046:Plant Stomata / Q000166:cytology / Q000378:metabolism*; D030821:Plants, Genetically Modified; D013997:Time Factors; D031307:Vicia faba / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D010940:Plant Proteins; D000040:Abscisic Acid; D010105:Oxygenases; D049308:Dioxygenases; C109043:9-cis-epoxy-carotenoid dioxygenase; C470342:AAO3 protein, Arabidopsis; D042931:Aldehyde Oxidase