Regulation of phytochrome message abundance in root caps of maize. Spatial, environmental, and genetic specificity

In many cultivars of maize (Zea mays L.) red light affects root development via the photomorphogenetic pigment phytochrome. The site of perception for the light is the root cap. In the maize cultivar Merit, we investigated phytochrome-mediated events in the cap. We established that the message encod...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1991-02, Vol.95 (2), p.544-550
Main Authors: Johnson, E.M. (University of California, Berkeley, CA), Pao, L.I, Feldman, L.J
Format: Article
Language:English
Subjects:
Autoregulation
Biological and medical sciences
CAPA PILIFERA
COIFFE
Corn
ETAPAS DE DESARROLLO DE LA PLANTA
Fundamental and applied biological sciences. Psychology
Gene expression regulation
Gravitropism
LUMIERE
LUZ
Messenger RNA
Metabolism
PIGMENT
PIGMENTOS
Plant physiology and development
Plant roots
Plants
Root cap
Root tips
Seedlings
STADE DE DEVELOPPEMENT VEGETAL
Storage and secretion, pigments, phytochrome
VARIACION GENETICA
VARIATION GENETIQUE
VARIEDADES
VARIETE
ZEA MAYS
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Summary:In many cultivars of maize (Zea mays L.) red light affects root development via the photomorphogenetic pigment phytochrome. The site of perception for the light is the root cap. In the maize cultivar Merit, we investigated phytochrome-mediated events in the cap. We established that the message encoded by the phyA1 gene was most abundant in dark-grown tissue and was asymmetrically distributed in the root cap, with greatest expression in the cells which make up the central columella core of the cap. Phytochrome message was negatively autoregulated in a specific region within the root cap. This autoregulation was sensitive to very-low-fluence red light, and thus was characterized as a phytochrome-mediated, very-low-fluence event. The kinetics of message reaccumulation in the dark were also examined and compared to the kinetics of the light requirement for root gravitropism in this cultivar. Similarly, the degree of autoregulation present in two other maize cultivars with different light requirements for gravitropic sensitivity was investigated. It appears that the Merit cultivar expresses a condition of hypersensitivity to phytochrome-mediated light regulation in root tissues. We conclude that phytochrome regulates many activities within the cap, but the degree to which these activities share common phytochrome-mediated steps is not known
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.95.2.544