Reference "Purification, characterization, and molecular cloning of basic PR-1-type pathogenesis-related proteins from barley"

Reference ID

8720

Title

Purification, characterization, and molecular cloning of basic PR-1-type pathogenesis-related proteins from barley

Source

Molecular plant-microbe interactions : MPMI, 1994, vol. 7, pp. 267-275

Authors (6)

Bryngelsson-T	Sommer-Knudsen-J
Gregersen-P-L	Collinge-D-B
Ek-B	Thordal-Christensen-H

Abstract

Partial amino acid sequences of two proteins, purified from barley leaves
reacting hypersensitively to the powdery mildew fungus, showed a high degree of
amino acid identity to the PR-1 proteins originally described in tobacco. The
proteins, subsequently designated HvPR-1a and HvPR-1b, show apparent pI values
of approximately 10.5 and 11, respectively and apparent M(r) 15,000.
Independently, differential screening of a cDNA library prepared from barley
leaves, exhibiting a compatible interaction with the powdery mildew fungus,
resulted in isolation of cDNA species representing two PR-1 homologs. With the
exception of one amino acid, the partial amino acid sequences of HvPR-1a and HvPR-
1b are identical to internal sequences of the polypeptides derived from the two
cDNA species. These derived polypeptides are each 164 amino acids long and both
have putative N-terminal leader sequences of 24 amino acids. That these proposed
leader sequences are functional is indicated by the observed occurrence of both
proteins in the intercellular fluid. The proposed mature proteins (calculated
M(r) 14,490 and 15,204) share 91% identical amino acids with each other and 56
to 74% with other PR-1 proteins. Northern blot hybridization and immunoblotting,
respectively, show that both transcripts and both proteins accumulate following
inoculation of susceptible and hypersensitivity resistant barley leaves with the
powdery mildew fungus.