3.4 Endophytic Fungi in Phytoremediation
Phytoremediation is one of the approaches in which living green plantsin situare
used for bioremediation. They have the ability to decrease and/or removing con-
taminants from soil, water, sediments and air. Numerous recent studies have
demonstrated that endophytic microorganisms can accelerate these processes
effectively by interacting closely with their host plants (Li et al. 2012 ). Endophytic
Neotyphodium coenophialumandNeotyphodium uncinatumboth were found to be
successfully removed PAH and TPH from rhizosphere by two grass species
Festucaarun dinacea Schreb and F.pratensis Hude (Soleimani et al. 2010 ).
Espinosa et al. ( 2005 ) demonstrated that phytoremediation of hydrocarbon con-
taminated soil withCyperuslaxusinoculated with endophytic fungi. Similarly,
phytoremediation efficiency of wheat, mungbean and eggplant grown in hydro-
carbon contaminated soil was reported by Rabie et al. ( 2005 ). Recently
Cruz-Hernandez et al. ( 2013 ) demonstrated the removal of polyaromatic hydro-
carbons byFestuca aruninaceaefrom both perlite and soil by endophyticLewia
sp. The inoculated plants exhibited higher phenanthrene degradation (100%) as
compared to non-inoculated plants in perlite and soil.
Fungi are highly resistant to heavy metal pollution (Jordan and Lechevelier
1975 ) and play very important role in element cycling and mineral transformations
(Gadd 2007 ). The mechanism of metal tolerance in fungi includes metal adsorption
and immobilization, complexing and quanti-valence changing (Collin et al. 2003 ;
Gadd 2007 ). Fungal cell wall contains various active groups such as hydrosulphide
carboxyl hydroxyl which could respond to heavy metal ions and precipitate on the
surface of the cell wall (Shen et al. 2006 ). It was found that dark septate endophytic
fungi tolerant to environmental metal pollution and accumulates heavy metal
in vitro (Zhang et al. 2008 ; Ruotsalainen et al. 2007 ). Generally, endophytes which
live in host roots are similar to mycorrhizal fungi in many aspects (Brundett 2006 ).
The fungal endophytes have been shown to ameliorate metal toxicity for their
plant hosts by restricting the uptake of toxic metals and improving the supply of
essential elements (Likar et al. 2011 ) in red plant biomass despite higher Cu and Zn
accumulation in plant roots through expression of certain genes together with
increased free and conjugated polyamine levels (Cicatelli et al. 2010 ). Endophytic
fungi may increase host tolerance towards biotic and abiotic stresses. The plants
inoculated with endophytic fungi exhibited higher biomass production and higher
potential to accumulate Cd in roots and shoots than fungi free plants (Soleimani
et al. 2010 ).
In another study, endophytic Trichoderma sp. associated with Acacia
auriculoformisproduced more fresh weight than control plants and also increased
the translocation factors and metal bio concentration on growth of mustard,
(Brassica junceaL.) grown on Cd and Ni contaminated soils (Jiang et al. 2008 ). In
a phytoremediation study, the endophyticMucorsp. enhanced the phytoremedia-
tion potential of rape roots grown in soil contaminated with Pb and Cd. Deng et al.
( 2013 ) proposed an efficient method of phytoremediation by constructing mutant by
3 Endophytic Fungi Bioremediation 53