Cell wall proteins of in vitro cultured chili pepper lines differing in water stress tolerance

As a strategy to understand cellular mechanisms of drought tolerance, we analyzed the electrophoretic pattern of cell wall proteins from non adapted cells (ST) and a 15%25 polyethylenglycol (PEG)-tolerant clone (T7) of chili pepper (Capsicum annuum). To separate proteins bound to structural polymers by non-covalent links or disulfide bonds, cell walls were treated with sodium dodecyl sulphate (SDS), urea and 2-mercaptoethanol. After treatment three major proteins with apparent molecular masses of 9, 11 and 14 kDa accumulated in higher quantities in clone T7 than in ST cells. Cell walls were also solubilized with commercial lytic enzymes, such as lyticase and cellulase, to separate proteins joined by covalent bonds. The main difference was the presence of a new band with an apparent molecular mass of 10 kDa (p10) in clone T7 but not in ST cells. This band was also evident after autodigestion of walls by hydrolytic enzymes. Since p10 was liberated by cellulase and lyticase we suggest that this protein is covalently attached to the cellulose and glucan skeleton in clone T7. The potential role of p10 on the mechanism of drought tolerance is discussed.

Capsicum annuum; Cell wall proteins; Drought tolerance article; cell wall; nonhuman; pepper; plant cell; protein analysis; protein binding; stress

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