Effect of Endophytic Fungi on Cadmium Tolerance and Bioaccumulation byFestuca ArundinaceaandFestuca Pratensis

Abstract

Endophytic fungi are a group of fungi that live asymptomatically inside plant tissue. These fungi may increase host plant tolerance to biotic and abiotic stresses. The effect of Neotyphodium endophytes in two grass species (Festuca arundinacea and Festuca pratensis) on cadmium (Cd) tolerance, accumulation and translocation has been our main objective. The plants were grown in a hydroponic system under different Cd concentrations (0, 5, 10, and 20 mg L(-1)) for 6 weeks. They were also grown in soil spiked with different concentrations of Cd (0, 10, 20, and 40 mg kg(-1)) for 2 months. The results from all Cd treatments showed higher biomass production (12-24%) and higher potential to accumulate Cd in roots (6-16%) and shoots (6-20%) of endophyte-infected plants than endophyte-free plants. Cadmium accumulation by plants indicated that the grasses were capable of Cd hyperaccumulation, a property that was augmented after endophyte infection. Maximum photochemical efficiency of photosystem II (Fv/Fm) revealed that Cd stress was significantly reduced in endophyte-infected plants compared to non-infected ones.

Biotransformation potential of hexavalent chromium by Bacillus pumilus-S4, Pseudomonas doudoroffii-S5 and Exiguobacterium-S8 in association with hydrophytes

“…Becerra-Castro et al (2009) investigated bacterial assisted phytoremediation where bacterial strains could solubilise Ni in the soil and potentially improve phytoextraction strategies. The endophytic fungi Neotyphodium not only increase the host plant tolerance to cadmium stress, but also caused more accumulation of Cd in root and shoot of Festuca arundinacea and Festuca pratensis (Soleimani et al 2010). In another study by Abou-Shanab et al (2003), chromium-resistant bacteria helps Eichornia crassipes plants for the removal/phytoremediation of chromium in wastewater.…”

Enhancing Phytoremediation Efficiency in Response to Environmental Pollution Stress

“…In this regard using of arbuscular mycorrhizal fungi (AMF) that are naturally present in the roots of most plant species where they form a mutualistic association, as well as endophytic fungi which live systemically within the aerial portion of many grass species, can improve plant tolerance to biotic and abiotic stresses (Hildebrandt et al, 2007;Kuldau & Bacon 2008;Lingua et al, 2008;Soleimani et al, 2010a). The role of these groups of fungi on reducing abiotic stresses is mentioned in the following.…”

“…Since roots are not photosynthetical tissues, whereas metal stress could adversely affect CO 2 uptake, electron transport in chloroplasts by damaging photosystem I and II in leaves, proteomic changes in plant tissues upon an abiotic stress exposure would be different (Kieffer et al 2009). Hence, plant exposed to high level of heavy metals causes reduction in photosynthesis, water and nutrient uptake, growth inhibition and finally death (Yadav, 2010;Soleimani et al, 2010a;Kieffer et al 2009). The biosynthesis of ethylene as a gaseous plant hormone could be induced in response to environmental stressors which affect germination, growth and development of plant species as well as defence and resistance (Glick, 2004;Kang et al, 2010).…”

Levels of Organic Compounds, Number of Microorganisms and Cadmium Accumulation in Festuca ovina Hydroponic Culture

“…Plants are colonized by endophytic and rhizospheric micro organisms which increase the resistance of their hosts to environmental stresses (Jha et al, 2013). These microorganisms can play an important role in phyto remediation of soils polluted with heavy metals (Soleimani et al, 2010) and many other, especially organic, contaminants (Gerhardt et al, 2009).…”

“…Plants are colonized by endophytic and rhizospheric micro organisms which increase the resistance of their hosts to environmental stresses (Jha et al, 2013). These microorganisms can play an important role in phyto remediation of soils polluted with heavy metals (Soleimani et al, 2010) and many other, especially organic, contaminants (Gerhardt et al, 2009).Organic components of root exudates are a good source of nutrients and energy for microorganisms, hence, a microbial community living in the rhizo sphere can be 10-100 times larger than the same type of community found in bulk soil (Huang and Germina, 2002). Understanding the microbiological, biochemical and physiological aspects of phytoremediation of soil and water environments polluted to different degrees with heavy metals has very important theoretical and practical implications.…”