Induction of beta-glucosidase activity in maize coleoptiles by blue light illumination.
The role of beta-glucosidase during the phototropic response in maize (Zea mays) coleoptiles was investigated. Unilateral blue light illumination abruptly up-regulated the activity of beta-glucosidase in the illuminated halves, 10 min after the onset of illumination, peaking after 30 min and decreasing thereafter. The level of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), which is released from DIMBOA glucoside (DIMBOA-Glc) by beta-glucosidase, and its degradation compound 6-methoxy-benzoxazolinone (MBOA) were elevated within 30 min in the illuminated halves as compare to the shaded halves, prior to the phototropic curvature. Furthermore, beta-glucosidase inhibitor treatment significantly decreased the phototropic curvature and decreased growth suppression in the illuminated sides. These results suggest that blue light induces the activity of beta-glucosidase in the illuminated halves of coleoptiles causing an increase in DIMBOA biosynthesis and the growth inhibition that leads to a phototropic curvature.
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
Riffat
R
Jabeen
Kosumi
K
Yamada
Hideyuki
H
Shigemori
Tsuyoshi
T
Hasegawa
Masakazu
M
Hara
Toru
T
Kuboi
Koji
K
Hasegawa
D048588:Benzoxazines; D001583:Benzoxazoles / Q000378:metabolism; D018548:Cotyledon / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D005942:Gluconates / Q000494:pharmacology; D005947:Glucose / Q000031:analogs & derivatives / Q000494:pharmacology; D005960:Glucosides / Q000378:metabolism; D008027:Light; D010078:Oxazines / Q000378:metabolism; D018524:Phototropism / Q000187:drug effects / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation; D003313:Zea mays / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
C418135:2-O-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one; D048588:Benzoxazines; D001583:Benzoxazoles; D005942:Gluconates; D005960:Glucosides; D010078:Oxazines; D010940:Plant Proteins; C031896:6-methoxybenzoxazolinone; C018399:1-thioglucose; D001617:beta-Glucosidase; D005947:Glucose; C050733:2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one