Effective biofertilizer trichoderma spp. isolates with enzymatic activity and metabolites enhancing plant growth

Abstract

Trichoderma species have been widely recognized as biofertilizer fungi for their ability to produce phytohormones and enhancing plant growth. In our current study, fifteen strains of Trichoderma spp (T1- T15) were screened for their capacity to produce phytohormones and metabolites eliciting plant growth. The stains were previously isolated from olive rhizosphere soil in northern Algeria. Plant growth promoting (PGP) potential of Trichoderma spp. was evaluated in-vitro through the production of phosphatases, iron chelators (siderophores), cyanhydric acid (HCN) and ammonia (NH3). Besides, Plant growth phytohormones such as gibberellic acid and indole-3-acetic acid (IAA) were assessed quantitatively by a colorimetric assay. Results showed an effective potential of Trichoderma isolates in PGP biomolecules production. Importantly, qualitative estimation of phosphate solubilization indicates that T10 gave the highest P-solubilization on medium Pikovskaya’s with a solubilization index (SI) of 3, whereas, the high capacity nitrogen-fixing was related to T8. In other hand, quantitative analysis of IAA and gibberellic acid revealed a production varying between (1.30 µg mL − 1 − 21.15 µg mL − 1 ) and (0.53µg/ml − 7.87µg/ml), respectively, the highest amount of both phytohormones was obtained by T11 isolate. Indeed, analysis of ethyl acetate extracts of T11 isolate by high-performance liquid chromatography (HPLC) revealed a high amount (71.19 mgL − 1 ) of IAA. Overall, Results showed clearly that isolate T11 has promising plant growth promoting properties. Hence, this native Trichoderma isolate (T11) identified as Trichoderma harzianum strain (OL587563) could be used later as biofertilizer for sustainable olive crop agriculture