ISSN:
1573-5028
Keywords:
antifungal proteins
;
non-host resitance
;
pathogenesis-related protein
;
proteinase inhibitor
;
Septoria nodorum
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Two previously unidentified cDNA clones (bsi1 and bpr1–1) were isolated by differential hybridization from a cDNA library of Stagonospora (Septoria) nodorum (Berk) Castellani & E.G. Germano teleomorph Phaeosphaeria (Leptosphaeria) nodorum (E. Muller) Hedjaroude-challenged barley (Hordeum vulgare L.) coleoptiles. bsi1 encoded a cysteine-rich protein containing 89 amino acids (aa) with a relative molecular mass (M r) of 9405. Protein sequence homologies showed that Bsi1 was very similar to an aluminium-induced protein from wheat and indicated that it was related to the Bowman-Birk-type proteinase inhibitors (BB-PIs). The predicted aa sequence of Bsi1 contained an N-terminal secretory signal sequence which implied that the protein was exported. The other clone, bpr1–1, which was truncated at the 5′ end, encoded a type-1 pathogenesis-related (PR-1) protein. The complete sequence of bpr1–1 was obtained after cloning a barley genomic DNA fragment and was shown to encode a basic protein containing 174 aa with a M r of 18 859. The deduced aa sequence of bpr1–1 contained both an N-terminal secretory signal sequence and a charged C-terminal extension. This latter sequence may represent a vacuolar targeting signal. bsi1 and bpr1–1 and four other defence-related genes (encoding 1,3-β-glucanase, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, a homologue of a putative wheat peroxidase, and barley leaf-specific thionin), showed increased transcription levels in S. nodorum-challenged coleoptiles, although their pattern of accumulation varied after inoculation (a.i.). The potential role of these induced genes in defence against fungal attack is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00019462
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