Comparative study of two groups of b proteins (pathogenesis related) from the intercellular fluid of Nicotiana leaf tissue infected by tobacco mosaic virus

1985 ◽  
Vol 63 (5) ◽  
pp. 932-937 ◽  
Author(s):  
Marc G. Fortin ◽  
Jean-Guy Parent ◽  
Alain Asselin

A time-course study showed that the major extracellular b (pathogenesis-related) proteins were detected approximately 37 h after tobacco mosaic virus infection of Nicotiana tabacum L. cv. Xanthi-nc tobacco leaf tissue. Silver staining of b1b2 and b3 proteins in native polyacrylamide gels required previous staining with Coomassie blue. Elution profiles of b4, b5, and b6b proteins from DEAE-Sephacel columns were similar to those of b1b2, and b3 proteins. Relationships among b proteins accumulating in the intercellular fluid of hypersensitive cv. Xanthi-nc tobacco leaves infected by tobacco mosaic virus were examined on the basis of serological relationships and by comparing peptide fragments. Results showed that b4, b5, and b6b proteins share common antigenic determinants and polypeptide fragments different from those shared by b1b2, and b3 proteins. Together with the close similarity of the molecular weights of the proteins within each group, these data suggest that at least two groups of related proteins are found in the intercellular fluid extracts of tobacco plants infected by tobacco mosaic virus. It is also shown that the antigenic determinants shared within the b4, b5, and b6b group are found with the same b proteins from systemically infected N. tabacum L. cv. Samsun and with some b proteins from N. sylvestris Speg. and Comes.

1984 ◽  
Vol 62 (3) ◽  
pp. 564-569 ◽  
Author(s):  
Jean-Guy Parent ◽  
Alain Asselin

In tobacco mosaic virus infected hypersensitive Nicotiana species, the pathogenesis-related (PR) or b proteins were found with other proteins in the intercellular fluid of leaf tissue. Analysis of leaves from mock-inoculated plants did not reveal the presence of detectable amounts of proteins in the intercellular fluid. The presence of proteins in the intercellular fluid seems to be widespread since 10 proteins were detected in tobacco mosaic virus infected Chenopodium quinoa Willd. These proteins were found not only in inoculated tissue but also in the intercellular fluid of uninoculated upper leaves. A two-dimensional gel electrophoretic analysis of intercellular fluid proteins from N. tabacum L. cv. Xanthi-nc infected leaves showed that the relative molecular weight of protein b2 is larger (14 700) than the one of b1 and b3 (14 200). Other proteins, ranging in molecular weights from 12 500 to 36 300, could also be detected. We postulate that the presence of rather large amounts of proteins, including the well-characterized b proteins, in the intercellular fluid of infected hypersensitive leaves reflects overall changes in cell-to-cell interactions and in the cell wall metabolism.


1988 ◽  
Vol 66 (6) ◽  
pp. 1227-1229 ◽  
Author(s):  
Jean Grenier ◽  
François Côté ◽  
Alain Asselin

In addition to polyacrylamide gel electrophoretic analysis of intercellular fluid extracts, a simple method of detection of extracellular pathogenesis-related proteins was based on direct native polyacrylamide gel electrophoresis for acidic and basic proteins with leaf tissue infiltrated with 150 mM sucrose. This technique allowed for the detection of the complete set of tobacco pathogenesis-related proteins without having to extract the intercellular fluid by low-speed centrifugation. A major advantage of the technique is the capacity to observe the distribution of extracellular endogenous or exogenous proteins in the tissue directly subjected to electrophoresis.


1987 ◽  
Vol 65 (3) ◽  
pp. 476-481 ◽  
Author(s):  
Richard Hogue ◽  
Alain Asselin

By using two-dimensional polyacrylamide gel electrophoresis, 10 additional pathogenesis-related proteins (b6c, b9c, b10a, b10b, b11a, b11b, b12, b13, b14, b15) were found in intercellular fluid extracts of stressed 'Xanthi-nc' tobacco leaf tissue. Proteins were identified as extracellular pathogenesis-related stress proteins by polyacrylamide gel electrophoresis analysis of three successive intercellular fluid extracts compared with homogenates before and after making intercellular fluid extracts. Four proteins (b12, b13, b14, b15) were only resolved by using native polyacrylamide gel electrophoresis for basic proteins in the first dimension gel and they were best extracted in 0.05 M Tris–HCl (pH 7.5) and 0.05 M CaCl2 as the infiltration buffer. The four basic proteins were found in intercellular fluid extracts from leaf tissue subjected to the same types of chemical inducers as previously described for tobacco pathogenesis-related proteins. Their accumulation was inhibited by basic amino acids or spermidine (1 mM) and they were resistant to endogenous and exogenous (trypsin, subtilisin) proteolysis. They did not bind to concanavalin A – Sepharose. These findings indicate that at least 23 proteins accumulate extracellularly after various types of stress in 'Xanthi-nc' tobacco green tissue. These proteins probably represent several groups or families of plant stress proteins.


1987 ◽  
Vol 7 (4) ◽  
pp. 1580-1583 ◽  
Author(s):  
J P Carr ◽  
D C Dixon ◽  
B J Nikolau ◽  
K V Voelkerding ◽  
D F Klessig

The PR1 family of pathogenesis-related proteins from tobacco (Nicotiana tabacum L.) leaves is induced by a variety of pathogenic and chemical agents and is associated with resistance to tobacco mosaic virus. The majority of the PR1 proteins did not copurify with mesophyll protoplasts (the major cell type of the leaf) isolated from tobacco mosaic virus-infected N. tabacum cv. Xanthi-nc leaves. However, these isolated protoplasts were capable of synthesizing and selectively secreting the PR1 proteins. Using monoclonal antibodies for immunofluorescence microscopy, we localized these proteins to the extracellular spaces predominantly in regions adjacent to viral lesions as well as in xylem elements of infected leaves.


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