Myco-phytoremediation of arsenic- and lead-contaminated soils by Helianthus annuus and wood rot fungi, Trichoderma sp isolated from decayed

In the present study, Helianthus annuus grown in arsenic- (As) and lead- (Pb) contaminated soil were treated with plant-growth promoting fungi Trichoderma sp. MG isolated from decayed wood and assessed for their phytoremediation efficiency. The isolate MG exhibited a high tolerance to As (650 mg/L) and Pb (500 mg/L), and could remove > 70% of metals in aqueous solution with an initial concentration of 100 mg/L each. In addition, the isolate MG was screened for plant-growth-promoting factors such as siderophores, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, indole acetic acid (IAA) synthesis, and phosphate solubilisation. Phytoremediation studies indicated that treatment of H. annuus with the isolate MG had the maximum metal accumulation in shoots (As; 67%, Pb; 59%). Furthermore, a significant increase in the soil extracellular enzyme activities was observed in myco-phytoremediated soils. The activities of phosphatase (35 U/g dry soil), dehydrogenase (41 mg TPF/g soil), cellulase (37.2 mg glucose/g/2 h), urease (55.4 mg N/g soil/2 h), amylase (49.3 mg glucose/g/2 h) and invertase (45.3 mg glucose/g/2 h) significantly increased by 12%, 14%, 12%, 22%, 19% and 14% in As contaminated soil, respectively. Similarly, the activities of phosphatase (31.4 U/g dry soil), dehydrogenase (39.3 mg TPF/g soil), cellulase (37.1 mg glucose/g/2 h), urease (49.8 mg N/g soil/2 h), amylase (46.3 mg glucose/g/2 h), and invertase (42.1 mg glucose/g/2 h) significantly increased by 11%, 15%, 11%, 18%, 20% and 14% in Pb contaminated soil, respectively. Obtained results indicate that the isolate MG could be a potential strain for myco-phytoremediation of As and Pb contaminated soil.