Enhanced phytoremediation of multi-metal contaminated soils by interspecific fusion between the protoplasts of endophytic Mucor sp. CBRF59 and Fusarium sp. CBRF14

The aim of this study was to isolate protoplasts from different metal resistant endophytic fungi and to carry out interspecific fusion of protoplasts to enhance bioremediation of contaminated soils. Three stable fusants (F1, F2, and F3) with resistance to Cd and Zn were constructed by interspecific fusion between inactivated protoplasts from Cd-resistant endophytic Mucor sp. CBRF59 and Zn-resistant endophytic Fusarium sp. CBRF14. The fusants increased concentrations of water soluble Cd, Pb, and Zn in soils, promoted rape growth, increased metal concentrations in the rape, elevated the extractable metal amount, and increased metal translocation from roots to shoots in soils containing single metals or multi-metals. Especially, the fusants showed much higher extraction efficacy than the parents in soils contaminated by multi-metals. The results indicated that protoplast fusion should be a feasible and efficient fungal method, which could be utilized to construct stable fusants by combining the genetic traits of parents for bioremediation of contaminated soils by multi-metals.