Inhibition of pre-symbiotic hyphal growth of arbuscular mycorrhizal fungus<i>Gigaspora margarita</i>by root exudates of<i>Lupinus</i>spp.

Abstract

Abstract Effect of root exudates of Lupinus plants on hyphal growth of arbuscular mycorrhizal (AM) fungus was investigated in order to elucidate the failure of mycorrhizal colonization in nonhost plants. Four species of Lupinus were grown in solution culture and root exudates were collected. Spores of Gigaspora margarita were incubated with the root exudates. Hyphal length in the root exudates of L. luteus, L. aridus, and L. cosentini was shorter than that of the control treatment, irrespective of the P status of Lupinus plants. Numbers of hyphae exhibiting branching were lower in the root exudates of L. luteus and L. cosentini than in those of the controls. It is suggested that these Lupinus plants did not induce pre-symbiotic hyphal growth of AM fungi but inhibited it.