Isolation and Characterization of the Mycorrhiza Helper Bacteria from the Fairy Rings of Floccularia Luteovirens

Floccularia luteovirens is an edible ectomycorrhizal fungus which forms fairy rings (FRs) distributed on the Qinghai-Tibet Plateau. Our previous study found four isolates of potential mycorrhiza helper bacteria (MHB), but they were only isolated from a single FR and their mycorrhizal promoting ability was not tested. Thus, it was necessary to collect samples from a larger area and measure the mycorrhizal promoting ability of the potential candidates. Of 184 bacterial isolates from five fairy rings located in Qinghai-Tibet Plateau belonging to 12 species, and 7 of them (58.3%) significantly promoting the growth of F. luteovirens. We also tested the symbiosis-promoting ability of the isolates, and the results showed that only four of them stimulated the formation of mycorrhizal symbiosis. This is the first report of the construction of mycorrhizal symbiosis between F. luteovirens and its host plant in greenhouse conditions. Our results showed that the strain A89 (Achromobacter marplatensis) could produce antifungal properties but nonetheless stimulated the fungal growth. This may due to the nutrient condition of medium and the genotype specificity of MHBs. The results suggest that the promotion of significant growth is not a good predictor for mycorrhiza formation promotion ability of MHB.

EFFECTS OF COMBINED INOCULATION OF BAMBARA GROUNDNUT (Vigna subterranean L. Verdc.) WITH GLOMUS MOSSEA AND BRADYHRHIZOBIUM JAPONICUM ON NITROGEN AND PHOSPHOROUS UPTAKE IN SHOOT, PLANT BIOMASS, LEAF CHLOROPHYLL AND MYCORRHIZAL INOCULATION EFFICIENCY (MIE).

The response of Bambara groundnut to co-inoculation with Abuscular mychorrhizal fungi (G. mossea) and Bradhyrhizobium japonicum (strain USDA110) with regard to leaf chlorophyll, percentage shoot nitrogen and phosphorus, nodule weight and plant biomass was studied. Bambara plants were grown under screen house conditions in pots. Plants were inoculated with 1ml of B. japonicum USDA 110 strain (109 cfu /ml), Mychorrizal was applied to the plants 10g, and 20g (90 spores/g) and water was applied at 10ml, 20 ml and 50ml every other day. The obtained results showed that dual inoculation activity was able to improve both nitrogen and phosphorus in plant shoot, MIE, but did not improve biomass and leaf chlorophyll when compared with plants subjected to single inoculation with only G. mossea and only B. japonicum. More Nitrogen and Phosphorus was retained in the shoot of plants co-inoculated with B. japonicum and 20g G. mossea when given 50ml of water and also had higher biomass. Leaf chlorophyll reduced in plants as flowering approached. B. japonicum was able to positively influence and establish symbiosis with G.mossea and synergistically effectively act as “mycorrhiza helper bacteria” (MHB) when both were co-inoculated in Bambara plant.

The Application of PCR Reaction for Identification of MHB Bacteria Species

This study characterizes mycorrhiza helper bacteria (MHB) from selected unpolluted locations as well as subjected to industrial emissions. To determine the species of bacteria isolated from the roots of ectomycorrhizal pine and birch, a method based on the sequence analysis of a 16S rRNA gene was used. The isolated bacteria were initially characterized by available biochemical methods and phenotypic observation. On the selected bacteria representatives isolation of DNA was performed, on which the PCR reaction was carried out. In this way amplified samples were automatically sequenced and the obtained results were compared to public databases. Among the isolated bacteria Pseudomonas fluorescens SBW25 and Burkholderia xenovorans LB400 species were dominant.