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“ENDEGRADE” Endophytic bacteria for improving phytoremediation. Fiona Porteous Moore, Colin Campbell, Edward Moore & E.U. partners. ENDEGRADE 7 project partners. SCOTLAND BELGIUM IRELAND DENMARK Macaulay IT Carlow Institute
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“ENDEGRADE”Endophytic bacteria for improving phytoremediation Fiona Porteous Moore, Colin Campbell, Edward Moore & E.U. partners
ENDEGRADE7 project partners SCOTLANDBELGIUM IRELAND DENMARK MacaulayIT Carlow Institute LUC VITO DEC-NV DTU NERI (INDUSTRIAL PARTNER)
PHYTOREMEDIATION • Ideally plants must have deep roots perennial large water use • Plants breakdown/volatilise compounds store them in leaves/shoots • 4 methodsphytovolatilisation phytoextraction rhizofiltration phytostabilisation
Problems with some current remediation strategies • Phytoremediation • pollutants kill the plants • volatilisation through leaves • partial degradation leading to toxic products • Soil bioremediation • indigenous population overcomes introduced degraders • nutrient applications often needed • pollutants can be taken up by plants faster than soil microbes can degrade them
Endegrade - the concept • enhance plant survival • enhance degradation • reduce volatilisation
Project aims • Isolate & identify bacteria from Willow and Poplar • Screen for natural degradation potential for target compounds • Equip endophytic bacteria with degradation plasmids • Assess re-colonisation and phytoremediation efficiency • Risk assessment for field use
What is known about endophytic bacteria? • neutral or beneficial effects on the plant • - direct plant growth-promoting activity • - N2-fixation • - disease suppression • - enhanced pest control • exist in all plant species examined • 103 - 105 cfu/gm plant tissue • highest numbers observed in the roots • bacteria remain localised in specific tissues
We do not know… • community dynamics & diversity • colonisation potential • plant specific relationships?
Relative frequencies of bacterial isolates, classified to the genus level, on the basis of 16S rDNA sequence analysis
Relative frequencies of isolates classified as Pseudomonas species, based upon 16S rDNA sequence analysis
Effect of tree species Multivariate analysis - presence / absence of isolates in different species of trees.
Napthalene degradation in Pea (proof of concept) Work by: Germaine et al, IT Carlow
Plant protection • Iris & VM1450 - 2,4-D protection (Germaine et al, IT Carlow) • Pea & PCB degraders - 4-chlorobiphenyl protection (Germaine et al, IT Carlow) • Lupine & VM1330- Toluene protection, reduced volatilisation, enhanced growth (Barac et al, LUC) • Toluene & TCE degrader constructs from Brassicanapus - to test in plantae degradation(Borremans et al, VITO)
Re-inoculation • K.Germain et al, FEMS Microbiol.Ecol, in press. • 3 endophytic isolates gfp/Kan marked and re-inoculated into Poplar (original host) • All strains colonised roots, and 2 strains colonised stems and leaves after 10 weeks
VM1449 (Ps. veronii) colony on root xylem of poplar tree 10 weeks after inoculation x1000
Current work • Endophytic construct in Poplar exposed to 2,4-D - does in degrade/protect? • 2,4-D degradation genes & colonisation • Seasonal community dynamics of endophytes - affects inoculation time/method • intra/inter species variation, seasonal dynamics, compartmentalisation
Acknowledgements Macaulay Institute - Renate Wendler, Duncan White NERI - Denmark - Uli Karlson DTU - Denmark - Stefan Trapp VITO - Belgium - Daniel van der Lelie, Brigitte Borremans LUC- Belgium - Jaco Vangronsveld, Licy Oeyen, Tanja Barac IT Carlow- Ireland - David Dowling, David Ryan, Keiran Germaine, Elaine Keogh DEC NV- Belgium - Siegried D’Haene, Gunther de Becker