Harnessing the Potentialities of Arsenic Resistant Fungal Endophytes for Improved Growth Promoting Traits under in vitro Condition

Abstract

Endophytic fungi enhance the plant’s ability to tolerate stressful conditions including heavy metal stress via secretion of numerous secondary metabolites. However, the role of heavy metal resistant fungal endophytes in growth promotion of plants in extreme environments is need to be understood. Therefore, eight endophytic fungal isolates having arsenic tolerance potential up to 2000 ppm explored from the arsenic stressed plants were subjected to various in vitro growth promoting traits viz., phytohormones production, phosphate solubilization, siderophore production, ammonia production, HCN production and ACC deaminase activity under normal and arsenic stress (100 ppm) condition. Indole acetic acid produced by fungal endophytes ranged between 120-610 μg/ mL, which was reduced to 50-340 μg/ mL when they were grown on arsenic induced medium. In the siderophore production test, fungal isolate S3P1S1 produced significantly higher siderophore (96 ± 0.002 μmol) compared to other isolates and reference culture.  In addition, HCN production was observed in only one isolate. Therefore, present study clearly identified specific traits in the fungal endophytes, which make them good candidates as PGPR and might contribute to plant adaption to arsenic contaminated soils. These fungal endophytes, possessing metal tolerance as well growth promoting properties under in vitro conditions could have vital implications for the agricultural sector if used as biofertilizer.