Transformed soybean (Glycine max) roots as a tool for the study of the arbuscular mycorrhizal symbiosis

Abstract

Ri T-DNA transformed roots have been used effectively in studying the interaction between various plant hosts and arbuscular mycorrhizal (AM) fungi. We investigated the in vitro monoxenic symbiosis between the AM fungus Glomus intraradices and transformed soybean roots (TSRs). Comparisons were made between TSR system and plants of the same genotype. The extraradical fungal structures generated in vitro culture showed normal development. Straight runner hyphae branched into short simple branched absorbing structures and spores were initiated. AM symbiosis was confirmed by the presence of arbuscules and vesicles in cortical cells of the TSRs. The frequency of intraradical colonization in TSRs was higher than in plants grown in soil, whereas the intensity values of intraradical colonization in TSR cultures were similar to those in whole plants. These results show that TSR cultures were able to support the growth and characteristic development of G. intraradices.