Growth and tolerance of fungal Rhizoctonia species to toxic xenobiotic chlorinated phenols.

WOLSKI E. A; MURIALDO S.; GONZALEZ F; ANDREU A.B.

Mar del Plata. Argentina

Congreso; SAIB 43th Annual Meeting; 2007

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Chlorinated phenols (CP) are toxic compounds which are used as fungicides and herbicides. Due to its toxicity, CP-laden soils demand an immediate decontamination, and bioremediation is an alternative to conventional clean-up. The success of this approach depends on finding microorganisms able to degrade and support unusual-high concentration of CP. Many filamentous fungi were isolated from contaminated soils and its tolerance to CP was tested, looking for a potential degradation strain. In this work, Rhizoctonia isolates were studied for their ability to growth and survive to toxic concentrations of CP. R. solani (AG-3) and binucleated Rhizoctonia (BNR) were grown on PDA plus 10 ppm of the following compounds: phenol (P), trichlorophenol (TCP), tetrachlorophenol (TECP) and pentachlorophenol (PCP). The presence of P in the culture medium did not affect the growth of both fungal isolates. When TECP and TCP were used, AG-3 and BNR grew slowly compared to controls. Using an arbitrary scale from 1= no growth, to 5= growth equal to control, both isolates show a scale of 4.  In contrast, with PCP the two isolates grew with a scale of 2. Also, macroscopic changes were observed in the mycelium of AG-3: concentric rings appeared in presence of CP. And both isolates showed a darker mycelium in presence of PCP. Future efforts will focus on the potential of these fungal isolates to degrade CP. Financiado por:  CONICET, UNMDP