PLEIOTROPIC EFFECTS OF PURINE AUXOTROPHY IN RHIZOBIUM-MELILOTI ON CELL-SURFACE MOLECULES

Rhizobial purine auxotrophs have earlier been shown to be defective in symbiosis, though the exact reason for this failure is not clear. Usi ng various dyes that specifically bind different cell surface molecule s, we show that there are multiple changes in the cell surface molecul es associated with different purine auxotrophs. Affected molecules in different purine auxotrophs that were tested include (i) acidic exopol ysaccharides, (ii) cellulose fibrils, and (iii) beta (1-3) glucans. Ou r results show that the symbiotic deficiency of purine auxotrophs is l ikely to be a result of these associated changes on the cell surface.