Abstract
Gibberellin (GA) regulates root growth. GA promotes the growth of Pisum sativum roots in the presence of ancymidol, an inhibitor of GA-biosynthesis. To investigate the role of cell wall proteins in root growth, we analyzed, by SDS-PAGE, the major bands of apoplastic proteins of pea roots treated with GA and/or ancymidol. GA-affected major proteins were sequenced and identified by homology search. Eight of eleven proteins affected by GA were sequenced. Three proteins homologous to pectin methylesterase (garden pea, mung bean) and to peroxidase (spinach, soy bean) were enhanced by GA. Five proteins were suppressed by GA. These were homologous to peroxidase (Medicago), chitinase class III (tobacco, rice, azuki) and cysteine proteinase (pea, Arabidopsis). Since nine of 13 proteins found in database contained signal sequences, most major proteins analyzed were conceived as apoplastic proteins with less contamination with cytoplasmic proteins. Role of these proteins in cell wall extension will be discussed.
