PLANT PHYSIOLOGY , Vol 101, Issue 1 193-199, Copyright © 1993 by American Society of Plant Biologists
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MOLECULAR BIOLOGY AND GENE REGULATION |
Identification of a Basic Glycoprotein Induced by Ethylene in Primary Leaves of Azuki Bean as a Cationic Peroxidase
F. Ishige, H. Mori, K. Yamazaki and H. Imaseki
Research Institute for Biochemical Regulation, School of Agricultural Sciences, Nagoya University, Nagoya, 464-01 Japan (F.I., K.Y., H.I.)
Ethylene causes the accumulation of seven different proteins (each
designated AZxx according to its molecular mass, xx in kD) in excised
primary leaves of azuki bean (Vigna angularis) (F. Ishige, H. Mori, K.
Yamazaki, H. Imaseki [1991] Plant Cell Physiol 32:681-690). A complementary
DNA encoding an ethylene-induced basic glycoprotein, AZ42, from azuki bean
was cloned and its complete nucleotide sequence was determined.
Characterization of the cDNA was accomplished by monitoring expression of
an immunoreactive protein in Escherichia coli that harbored the cDNA and by
the identification of a partial amino acid sequence that was the same as
that determined from the purified protein. An open reading frame (1071 base
pairs) in the cDNA encoded a protein of 357 amino acids with a molecular
mass of 39.3 kD. The amino acid sequence contained three regions that are
highly conserved among peroxidases from eight different plants. Purified
AZ42 exhibited peroxidase activity. The basic glycoprotein induced by
ethylene was identified as a cationic isozyme of peroxidase. The
corresponding mRNA was not present in leaves that had not been treated with
ethylene, but it appeared after 1 h of treatment with ethylene and its
level increased for the next 15 h. Accumulation of the mRNA was also
induced after wounding or treatment with salicylate. The wound-induced
increase in the level of the mRNA was suppressed by 2,5-norbornadiene, but
the salicylate-induced increase was not.
