The root endophytic fungus Curvularia geniculata from Parthenium hysterophorus roots improves plant growth through phosphate solubilization and phytohormone production

•Plant growth promoting ability of endophytic Curvularia geniculata was examined.•The fungus was isolated from roots of Parthenium hysterophorus.•Curvularia geniculata inoculated pigeon pea plants exhibited superior growth.•The fungus solubilized different sources of P and produced IAA.

The plant growth promoting ability of Curvularia geniculata (Tracy & Earle) Boedijn, a dark septate endophyte (DSE) fungus isolated from Parthenium hysterophorus L., was examined under in-vitro conditions for the first time. The abilities of the fungus to solubilize different sources of phosphorus (P) [AlPO4, FePO4 and Ca3(PO4)2] and to produce indole acetic acid (IAA) were also determined. C. geniculata-inoculated pigeon pea (Cajanus cajan) plants exhibited superior growth over uninoculated control plants and the fungus solubilized different sources of P in the order of FePO4>AlPO4>Ca3(PO4)2. The pH of the culture medium, fungal biomass production and acid phosphatase activity was significantly influenced by phosphate source and incubation period. IAA production, confirmed by chromatographic analysis, increased with increasing concentrations of tryptophan in a non-linear manner. It can be concluded from the results that C. geniculata mediates plant growth through phosphate solubilization and phytohormone production. This would enable the use of this fungus as bioinoculant in plant production systems.