LOCALIZATION OF A NUCLEAR-PROTEIN (QP47) IN EMBRYONIC MERISTEMS DURING SEED MATURATION AND GERMINATION AND ITS DISTRIBUTION AMONG CROP PLANTS

We report a desiccation-associated protein (QP47) which appears to be localized in the nucleoplasm of embryonic meristems during seed matura tion and seed germination. The variations of nuclear localization show n by this protein during seed maturation and germination might depend upon the nuclear and nucleolar rearrangement following variations in m oisture content in the seed tissues. The nucleolus is the compartment where the most obvious changes in chromatin organization take place. I t is suggested that this protein has a role in the protection of the n ucleus from desiccation. QP47 is present in nuclei of legumes, but not in cereals or recalcitrant seeds. In cereals, other nuclear proteins with a putative function similar to QP47 have been identified. The fac t that the quantitative variations of QP47 seem to be unique to an emb ryonic stage of plant development suggests that this protein may act a s an atypical desiccation protein with an additional function in stora ge. Such an additional storage function would also explain the restric ted occurrence of QP47 to members of the Leguminosae.