Endophytes in

Phytoremediation Jason Reynolds

A long intimate association

Colonize internal tissues without negative effects and with bacterial endophytes cause no external visible sign of infection.

Endophytic fungi found in 80% of plants.

Bacterial Endophytes have been found in nearly all plants.

Weyens, N., van der Lelie 2009

Plant roles in this Phytoremediation partnership

Uptake into the root is dependent

on plants. log Kow determines

potential for uptake of organics.

Evapotranspiration and Green

liver model.

Root exudation leads not only to

more diverse populations in the

rhizosphere but also in internal

plant tissues.

Dense and diverse population can

lead to stepwise transformation

by groups.

Additionally the microbial

diversity gives the possibility of

horizontal gene transfer.

Burkholderia phytofirman observed via fluorescence in

situ hybridization and gfp tagging (Compant2010)

Bacterial Endophytes

Inside cortex

Inside Xylem Production of plant hormones or

enzymes involved in growth.

Aid host plant in overcoming

toxic environmental contaminants.

Many beneficial plant bacteria,

produce high affinity

siderophores.

Use of molecules that kill or

inhibit growth of target pathogens.

Induced systemic resistance

produced by some known

beneficial bacteria.

(Weyens2009)

Endophytic bacteria aid in phytoremediation of 2,4-D

In 2001 13,000+ tons used in the

USA alone.

Very mobile so spreads to

groundwater.

Inoculation of Pisum sativum with

Pseudomonas putida from poplar

trees.

Phytoremediation of other

pollutants in 2,4-D treated

croplands.

(Germaine2006)

Arbuscular mychorhizae and their interaction with plants

Improve nutrient uptake

especially in low nutrient

condition.

Antioxidant enzymes increase in

plants with endophytes.

Increase uptake of less soluble

metals

Drought resistance

Pathogen resistance.

Phylum

Glomeromycota

contains all known

AM. 6000 known

species.

Radionuclide Remediation

Three North American native prairie grasses with high biomass in short time.

Inoculated with Glomus mosseae and Glomus intraradices.

Grown in a greenhouse on soil treated with 137Cs and 90Sr (sterilized).

Oak Ridge Nuclear Facility, near Oak Ridge, Tennessee.

Removal of 72% 137Cs and 82% 90Sr.

Inoculated plants grew better and faster leading to increased 137Cs and 90Sr uptake.

Chromium Phytoremediation with AM infected

sunflower

Partial alleviation of chromium toxicity: greater plant growth, increased net photsynthesis, and reduced visual symptoms of stress

High colonization occurred at the most toxic Cr treatments.

The effect of mycorrhizal inoculation on biomass was minimal low Chromium treatments

Cr did not affect root/shoot ratios. While, inoculated plants generally had a greater root/shoot

2.4-fold increase in net photosynthesis at high Cr with no change at lower

Verlag2001

Phytoextraction potential with a need for shoot and

root harvest?

Utilization of microbial genes for

Phytoremediation

Endophytic bacteria inoculated in poplar dissappear but the gene shows up in endogenous endophytes improving TCE uptake and reducing volatilization.

Soil microbes are closely related to many endophytes allowing further gene transfer and also possibly facilitating transgenics.

Alleviation of Cd toxicity by expression of metal binding peptide in Rhizobium

Abhilash, P. C., Powell, J. R., Singh, H. B., & Singh, B. K. (2012). Plant-microbe interactions: novel applications for exploitation in multipurpose remediation technologies. Trends in biotechnology, 30(8), 416–20. doi:10.1016/j.tibtech.2012.04.004

Blackwell, M. (2011). The fungi: 1, 2, 3 ... 5.1 million species? American journal of botany, 98(3), 426–38. doi:10.3732/ajb.1000298

Compant, S., Clément, C., & Sessitsch, A. (2010). Plant growth-promoting bacteria in the rhizo- and endosphere of plants: Their role, colonization, mechanisms involved and prospects for utilization. Soil Biology and Biochemistry, 42(5), 669–678. doi:10.1016/j.soilbio.2009.11.024

Doty, S. L. (2012). / Ias / V l ^ Er XVi |^ x Tansley review Enhancing phytoremediation through the use of transgenics and endophytes, 179(2), 318–333. doi:10.1111/J.1469-8137.2008.02446.X

Entry, J. A., Watrud, L. S., & Reeves, M. (2008). Accumulation of 137 Cs and 90 Sr from contaminated soil by three grass species inoculated with mycorrhizal fungi 1, 104(1999).

Germaine, K. J., Liu, X., Cabellos, G. G., Hogan, J. P., Ryan, D., & Dowling, D. N. (2006). Bacterial endophyte-enhanced phytoremediation of the organochlorine herbicide 2,4-dichlorophenoxyacetic acid. FEMS microbiology ecology, 57(2), 302–10. doi:10.1111/j.1574-6941.2006.00121.x

Giovannetti, M., & Gianinazzi-Pearson, V. (1994). Biodiversity in arbuscular mycorrhizal fungi. Mycological Research, 98(7), 705–715. doi:10.1016/S0953-7562(09)81041-1

Glick, B. R., Todorovic, B., Czarny, J., Cheng, Z., Duan, J., & McConkey, B. (2007). Promotion of Plant Growth by Bacterial ACC Deaminase. Critical Reviews in Plant Sciences, 26(5-6), 227–242. doi:10.1080/07352680701572966

Hildebrandt, U., Regvar, M., & Bothe, H. (2007). Arbuscular mycorrhiza and heavy metal tolerance. Phytochemistry, 68(1), 139–46. doi:10.1016/j.phytochem.2006.09.023

Newman, L. a, & Reynolds, C. M. (2005). Bacteria and phytoremediation: new uses for endophytic bacteria in plants. Trends in biotechnology, 23(1), 6–8; discussion 8–9. doi:10.1016/j.tibtech.2004.11.010

Ryan, R. P., Germaine, K., Franks, A., Ryan, D. J., & Dowling, D. N. (2008). Bacterial endophytes: recent developments and applications. FEMS microbiology letters, 278(1), 1–9. doi:10.1111/j.1574-6968.2007.00918.x

Taghavi, S., Barac, T., Greenberg, B., Vangronsveld, J., Lelie, D. V. D., & Borremans, B. (2005). Horizontal Gene Transfer to Endogenous Endophytic Bacteria from Poplar Improves Phytoremediation of Toluene Horizontal Gene Transfer to Endogenous Endophytic Bacteria from Poplar Improves Phytoremediation of Toluene. doi:10.1128/AEM.71.12.8500

Van Der Lelie, Daniel. "BIOINFORMATICS." Bioinformatics. Brookhaven National Laboratory, n.d. Web. 14 Nov. 2012. <http://www.technobioinfo.ewebsite.com/articles/www.endophtes.com.html>.

Verlag, F., Davies, F. T., Puryear, J. D., Newton, R. J., Egilla, J. N., & Grossi, J. A. S. (2001). Mycorrhizal fungi enhance accumulation and tolerance of chromium in sunflower ( Helianthus annuus ), 786.

Wang, B., & Qiu, Y.-L. (2006). Phylogenetic distribution and evolution of mycorrhizas in land plants. Mycorrhiza, 16(5), 299–363. doi:10.1007/s00572-005-0033-6

Weyens, N., van der Lelie, D., Artois, T., Smeets, K., Taghavi, S., Newman, L., Carleer, R., et al. (2009). Bioaugmentation with engineered endophytic bacteria improves contaminant fate in phytoremediation. Environmental science & technology, 43(24), 9413–8. doi:10.1021/es901997z

Weyens, N., van der Lelie, D., Taghavi, S., & Vangronsveld, J. (2009). Phytoremediation: plant-endophyte partnerships take the challenge. Current opinion in biotechnology, 20(2), 248–54. doi:10.1016/j.copbio.2009.02.012

Weyens, N., van der Lelie, D., Taghavi, S., Newman, L., & Vangronsveld, J. (2009). Exploiting plant-microbe partnerships to improve biomass production and remediation. Trends in biotechnology, 27(10), 591–8. doi:10.1016/j.tibtech.2009.07.006

Wu, C. H., Wood, T. K., Mulchandani, A., & Chen, W. (2006). Engineering Plant-Microbe Symbiosis for Rhizoremediation of Heavy Metals, 72(2). doi:10.1128/AEM.72.2.1129

Quiz

1. What is an endophyte?

2. Name one of the 3 pollutants I discussed/