Properties of secretory acid phosphatase from lupi

Authors: Jun Wasaki Michiko Ando Kenji Ozawa Masanori Omura Mitsuru Osaki Hiroyuki Ito Hirokazu Matsui Toshiaki Tadano

Publish Date: 1997

Volume: , Issue: , Pages: 295-300

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Abstract

Phosphorus deficiency induces the synthesis of acid phosphatases in roots of lupin and other plant species In this study we examined the induction of secretory acid phosphatase SAPase at both the molecular and cellular levels Lupin plants had increased levels of total acid phosphatase activity within two to five days after P was withered and levels approximately doubled by 15 days Lateral roots and not main tap roots were responsible for this increase in acid phosphatase activity Immunoblot analysis using antibodies raised against a purified SAPase showed that the synthesis of this protein was induced as early as 2 days in the P deficient treatment and that levels dramatically increased by 15 days In contrast no immunoreactive polypeptide was evident from crude extracts prepared from root tissues of P treated plants Immunocytochemical analysis revealed that the protein was located on the surface of epidermal cells of main tap roots and in the cell walls and intercellular spaces of lateral roots and lateral roots may actively secrete SAPase as soon as it is synthesized A cDNA clone encoding the SAPase was isolated from a cDNA library constructed from lupin roots grown without P The clone was 2187 bp in length and had a single open reading frame of 637 amino acid residues The deduced amino acid sequence was identical to the Nterminal region and peptide sequences of SAPase purified from lupin roots A hydrophobic signal peptide region consisted of 31 amino acids The primary structure was highly homologous to ironzinc purple acid phosphatase from Phaseolus vulgaris 76 secretory purple acid phosphatase from Arabidopsis thaliana 71 and two Aspergillus phosphate repressible acid phosphatases 59 and 58

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