Proteomic screening for potentially amyloidogenic proteins of Rhizobium leguminosarum in effective and ineffective root nodules of Pisum sativum L.

We studied potentially amyloidogenic proteins (e.g. protein forming polymers and complexes that are resistant to treatment with ionic detergents) in root nodules formed by two lines of garden pea (P. sativum L.): Sprint-2 (Fix+ phenotype) and Sprint-2Fix- (sym31) (Fix- phenotype) inoculated with the Rhizobium leguminosarum bv. viciae RCAM1026 root nodule bacteria. The Fix+ phenotype is characterized by effective (ability to fix nitrogen) root nodules formation. The Fix- line is a descendant of the Fix+ line and forms ineffective root nodules (unable to fix nitrogen) with undifferentiated bacteroids. We demonstrated the presence of both plant and bacterial proteins in detergent resistant fractions, including previously identified amyloid proteins RopA and RopB of R. leguminosarum and vicilin of P. sativum L.