L. Bolanos et al., Lectin-like glycoprotein PsNLEC-1 is not correctly glycosylated and targeted in boron-deficient pea nodules, MOL PL MICR, 14(5), 2001, pp. 663-670
Symbiosome development was studied in pea root nodules from plants growing
in the absence of boron (B), Rhizobia released into the host cells of nodul
es from B-deficient plants developed to abnormal endophytic forms with an a
ltered electrophoretic lipopolysaccharide pattern. Immunostaining after sod
ium dodecyl sulfate-polyacrylamide gel electrophoresis and electroblotting
of nodule homogenates with antibodies that recognize glycoprotein component
s showed that two previously described lectin-like glycoproteins (PsNLEC-1A
and PsNLEC-1B) did not harbor the carbohydrate epitope normally recognized
by specific monoclonal antibodies. Material derived from B-deficient nodul
es, however, still contained three antigenic isoforms with similar electrop
horetic mobilities to PsNLEC-1 isoforms A, B, and C, These could be detecte
d following immunoblotting and immunostaining with a specific antiserum ori
ginating from the purified PsNLEC protein that had been heterologously expr
essed in Escherichia coli, Immunogold localization of PsNLEC-1 sugar epitop
es in B-deficient nodules showed that they were associated mostly with cyto
plasmic vesicles rather than normal localization in the symbiosome compartm
ent of mature infected cells, These results suggest that a modification of
the glycosyl-moieties of PsNLEC-1 and an alteration of vesicle targeting oc
cur during the development of pea nodules in the absence of B, and that the
se changes are associated with the development of aberrant nonfunctional sy
mbiosomes.