Early events of vesicular–arbuscular mycorrhiza formation on Ri T‐DNA transformed roots

TLDR

The study aims to investigate the initial events of mycorrhiza formation using an in vitro system. An in vitro system employing Ri T‐DXA transformed roots and the vesicular–arbuscular mycorrhizal fungus *Gigaspora margarita* was developed. Sucrose, sodium, and phosphorus are essential for the medium, and a single spore inoculum reliably colonizes a preselected root point within five days, yielding abundant viable spores and enabling study of fungal biotrophy initiation.

Abstract

SUMMARY An in vitro system using Ri T‐DXA transformed roots and the vesicular–arbuscular mycorrhizal fungus Gigaspora margarita Becker & Hall has been developed to study the initial events of mycorrhiza formation. Sucrose, sodium and phosphorus were found to be critical components of the medium used to establish the dual culture. Using a single spore as inoculum it was consistently possible to obtain colonization of a preselected point on the root and to time the colonization process (within 5 days). Abundant viable and aseptic spores can be obtained. The system is especially appropriate for studying the triggering of the fungal biotrophy towards the root.