U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

PubAg

Main content area

Characterization of a new antifungal chitin-binding peptide from sugar beet leaves

Author:
Nielsen, K.K., Nielsen, J.E., Madrid, S.M., Mikkelsen, J.D.
Source:
Plant physiology 1997 v.113 no.1 pp. 83-91
ISSN:
0032-0889
Subject:
plant pathogenic fungi, binding proteins, gene expression, disease resistance, cysteine, leaves, antifungal properties, protein composition, messenger RNA, complementary DNA, genetic code, amino acid sequences, pathogenicity, hevein, glycine (amino acid), Beta vulgaris, chitin, Cercospora beticola, flowers, physicochemical properties, nucleotide sequences, niacin, chitinase
Abstract:
The intercellular washing fluid (IWF) from leaves of sugar beet (Beta vulgaris L.) contains a number of proteins exhibiting in vitro antifungal activity against the devastating leaf pathogen Cercospora beticola (Sacc.). Among these, a potent antifungal peptide, designated IWF4, was identified. The 30-amino-acid residue sequence of IWF4 is rich in cysteines (6) and glycines (7) and has a highly basic isoelectric point. IWF4 shows homology to the chitin-binding (hevein) domain of chitin-binding proteins, e.g. class I and IV chitinases. Accordingly, IWF4 has a strong affinity to chitin. Notably, it binds chitin more strongly than the chitin-binding chitinases. A full-length IWF4 cDNA clone was obtained that codes for a preproprotein of 76 amino acids containing an N-terminal putative signal peptide of 21 residues, followed by the mature IWF4 peptide of 30 residues, and an acidic C-terminal extension of 25 residues. IWF4 mRNA is expressed in the aerial parts of the plant only, with a constitutive expression in young and mature leaves and in young flowers. No induced expression of IWF4 protein or mRNA was detected during infection with C. beticola or after treatment with 2,6-dichloroisonicotinic acid, a well-known inducer of resistance in plants.
Agid:
664578