INVOLVEMENT OF THE FUNGAL ENDOPHYTE F . SOLANI IN THE PHOSPHATE NUTRITION OF LOTUS SPECIES

ROMERO F.M.; ERBAN A.; CARRASCO P.; RUIZ O.A.; NIEVA, A.S.; FEHRLER I.; KOPKA J.

JENA

Workshop; 8th International Conference on Microbial Communication; 2020

JENA UNIVERSITY

The fungal endophyte Fusarium solani (strain 142L52B), isolated from constrained soils, has the ability to infect roots of Lotus species in a symptomless way, displaying a differential response according to the plant species. The ability of F. solani to solubilize phosphate suggests a possible role in the improvement of the plant nutrition. The interaction between F. solani 142L52B and L. tenuis or L. japonicus causes a differential response according to the plant species, in regard to biomass, photosynthesis and sugar content. Our aim was to evaluate the behaviour of the plant response to the phosphate starvation stress in plants of L. tenuis and L. japonicus infected with F. solani, through systems analysis of the primary metabolome using GC-EI/TOF-MS technology. In addition, we evaluated primary metabolism of F. solani cultivated in-vitro, in order to determine the potential ability of the fungus to secrete compounds as well as to determine the compounds that it accumulates in the mycelia cells. Our results demonstrated that the endophyte F. solani increases organic phosphates in L. japonicus under optimal cultivation conditions. The endophyte caused decrease of the same compounds in L. tenuis. Nevertheless, the increase in some phosphate compounds did not correspond to the amount of total phosphorus in the plant tissues. In addition, the fungal endophyte did not ameliorate the stress caused by severe phosphate starvation. Some metabolites such as sugars, acids and polyols showed differential response to infection by F. solani and according to infected plant species. Our results suggest that severe phosphate stress masks the effect of plant interaction with the fungus despite the fact that the non-interacting fungus accumulates phosphoric acid from its substrate. We conclude that the endophyte fungus does not offer a fortification strategy to prevent plant phosphate starvation. We hypothesise that the fungus Lotus ssp. interaction may provide phosphate resources under mild nutrient limiting conditions.