Interaction between supernodulating or non-nodulating mutants of soybean and two arbuscular mycorrhizal fungi

Twelve nodulation mutants (seven non-nodulating and five supernodulating) o f soybean [Glycine max (L.) Mirr.] were screened for arbuscular mycorrhizal colonization in the presence of either Glomus etunicatum Becker and Gerdem ann or Gigaspora margarita Becker and Hall. The cultivars showed variation in colonization parameters. The two supernodulating mutants En6500 and NOD1 -3 had higher frequencies of colonization with 2.5-4.5 times higher arbuscu lar abundance than the respective wild types. The enhanced mycorrhization r esulted in significant enhancement of P uptake by En6500. The non-nodulatin g mutants showed decreases in mycorrhizal parameters. Mutants En1282 and Ha rosoy exhibited aborted infection after formation of typical appressorium-l ike structures at some sites. However, none of these had the non-mycorrhiza l phenotype. Growth and nutrient-uptake parameters should be considered whi le studying plant mutants for mycorrhization.