StGCPRP, a potato gene strongly expressed in stomatal guard cells, defines a novel type of repetitive proline‐rich proteins.
by Menke U, Renault N, Mueller‐Roeber B. (2000)
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam/Golm, Germany
Institut für Genetik, Freie Universität Berlin, Germany
Ulrich Menke
Nathalie Renault
in Plant Physiology 122,677–686. – doi: http://dx.doi.org/10.1104/pp.122.3.677 –
Abstract
Guard cells represent a highly differentiated cell type within the epidermis of plant leaves and stems. They respond to many endogenous and environmental signals and thereby modify the size of the stomatal pore they surround.
We identified a novel gene that is highly expressed in guard cells of potato (Solanum tuberosum). It encodes a repetitive proline (Pro)-rich protein of 54 kD (491 amino acids) and was named StGCPRP (S. tuberosumguard cell Pro-rich protein).
StGCPRP has a bipartite structure. The C-terminal part of StGCPRP contains a high percentage (46%) of Pro residues organized in distinct repetitive sequence motifs, whereas its extended N terminus is essentially free of Pros. StGCPRP represents the first member of a novel class of hybrid Pro-rich proteins that we designated NHyPRPs. In young but not in mature leaves, StGCPRP transcripts were also present at high levels in mesophyll cells (in addition to guard cells), indicating developmental regulation of StGCPRPgene expression.
In addition, StGCPRP expression is regulated by environmental factors, as shown by a decrease inStGCPRP transcript levels under drought stress. Two proteins similar to StGCPRP were found to be encoded by the Arabidopsis genome, indicating that NHyPRPs are more widely distributed in higher plants.
PLANT STOMATA ENCYCLOPEDIA 