Interactions between Frankia BCU110501 (actinorhiza) and Gigaspora rosea (arbuscular mycorrhiza) with Discaria trinervis studied by spot inoculation

Abstract

Root endosymbioses are associations between plants and soil microorganisms which contribute worldwide to plant nutrition and fitness. The most common associations is with arbuscular mycorrhizal fungi (AMF) and this is formed by the majority of land plants with fungi belonging to the Glomeromycota. Another important association is that formed by the Gram-positive actinobacteria, Frankia, and actinorhizal plants such as Discaria trinervis. In this paper we studied the effect of dual symbioses resulting from spot inoculation. This method was developed and tested to ensure actinorhizal nodule development only at the site of inoculation. Our results show that both symbioses can coexist and that AMF and Frankia can stimulate plant growth both as a single inoculum and in combination. Moreover, we suggest that there is no interference between the regulation of actinorhizal and arbuscular mycorrhizal symbiosis in D. trinervis, and that there is a synergistic effect on plant growth following the development of both symbioses.