Characterization of phosphate solubilizing fungal endophyte associated with roots of Coriandrum sativum L growing in water stressed soil

Exploration of novel endophytes with promising biofertilizer attributes is the focus of research worldwide. In this regard, fungal endophytes have gained considerable attention for their potential role in solubilizing rock phosphate (P). Plants growing in harsh environment are reported to harbor high profile endophytes that promote plant growth and development under stressful condition. The current study was an effort to decipher P-solubilization capacity of fungal endophytes associated with coriander roots, collected from water stressed soil. We recovered a single fungal endophyte inhabiting coriander roots. The isolated endophyte was identified as Rhizopus oryzae through 18 S gene sequencing and evaluated for P-solubilization. The strain was inoculated into six different P-sources and assessed periodically for free phosphates, pH and P-solubilizing enzymes for 25 days. The major mechanisms (organic acids and enzymes production) employed for solubilizing inorganic and organic phosphates were assessed. Solubilization index of 1.62 and 1.60 was recorded for PKV and APKV agar respectively. The quantities of P, released by the isolate were statistically significant for all six P-sources. Among the 6 supplemented P-sources, the highest solubilization was registered for tricalcium phosphate (51.45 ± 2.3 mg/L). A corresponding decrease in pH was recorded for every increase in solubilized P. The strain was noted for solubilizing organophosphates through the production of phosphatases and phytase enzymes. Taken together, the fungus was found efficient P-solubilizer and need trial inoculation to a variety of crops in field study.