Arbuscular mycorrhizal formation of crucifer leaf mustard induced by flavonoids apigenin and daidzein

Flavonoids from legume root secretion may probably act as signal molecules for expression of Rhizobial “nod” nodulation genes and AM fungal symbiotic gene. Leaf mustard is a non-mycorrhizal plant; it does not contain flavonoids and other signal molecules. AM fungi could not infect the roots of leaf mustard and form a symbiont in nature, when it was treated with flavonoids (apigenin or daidzein). The results of trypan blue staining showed that two kinds of AM fungi (G intraradices and G. mosseae) successfully infected the roots of non-mycorrhizal plant leaf mustard. AM fungi grew towards and colonized the roots of leaf mustard, producing young spores and completing the course of life. AM fungi are the only one kind of fungi with ALP activity. The result of ALP staining has also proved that AM fungi infected successfully the roots of leaf mustard. AM fungi (G intraradices and G. mosseae) that existed in the roots of non-mycorrhizal plant leaf mustard were probed by nested PCR and special molecular probes. The above-mentioned proof chains have fully proved that flavonoids induced AM fungi (G intraradices and G. mosseae) to infect non-mycorrhizal plant and establish symbiotic relationship.