1887

Abstract

Summary

Tomato ‘pathogenesis-related’ P1(p14) protein was synthesized . mRNAs were isolated from leaves showing characteristic symptoms of viroid infection, followed by chromatography on oligo(dT)-cellulose and the poly(A) fraction was translated with a rabbit reticulocyte lysate system. No significant differences were found between the levels of [S]methionine incorporation directed by mRNA preparations from healthy and viroid-infected leaves. Only mRNA from infected leaves incorporated label into a protein that could be immunoprecipitated with rabbit IgG specific for tomato P1(p14) protein. Analysis by SDS-PAGE of the immunoprecipitated protein from the translation system revealed that P1 (p14) was translated as a precursor protein of 2K to 3K larger than the P1(p14) that accumulated . This protein was converted to the mature form when translation was carried out in the presence of canine pancreatic microsomal membranes. By using Protein A-gold immunocytochemistry we have detected P1(p14) concentrated in dense inclusion bodies within the vacuole as well as in association with electron-dense material present in the intracellular spaces. The presence of the additional polypeptide sequence in the newly synthesized protein indicates that P1(p14) undergoes post-translational processing. The additional sequence is probably the signal peptide that directs its transport through the endoplasmic reticulum into the vacuolar compartment of tomato leaf cells and/or the intercellular space.

Keyword(s): PR protein , tomato plants and viroid
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/content/journal/jgv/10.1099/0022-1317-70-8-1933
1989-08-01
2019-11-14
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http://instance.metastore.ingenta.com/content/journal/jgv/10.1099/0022-1317-70-8-1933
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