IDENTIFICATION AND IMMUNOLOCALIZATION OF A 65 KDA DROUGHT-INDUCED PROTEIN IN CULTIVATED TOMATO LYCOPERSICON-ESCULENTUM

A 65 kDa protein with a pI value of 5.2 accumulated gradually in tomat o leaves during water stress. Protein levels returned to those of the control upon rehydration of the plants. Antiserum raised against the p rotein, purified from two dimensional electrophoresis gels, was obtain ed and used as a probe to localize the protein in tomato leaves by imm unofluorescence and immunogold labeling. The protein was found to be m ainly localized in different areas of nuclei (peripheral chromatin mas ses, nucleoli and nucleoplasm), chloroplasts, and some leaf cell cytop lasmic regions. Quantification of the gold labeling clearly demonstrat ed that the amount of the protein increased significantly in nuclei an d chloroplasts of cells in drought-stressed plants. Cytological change s occurring in leaf tissues during water stress are also reported.