Final Report Summary - PLANT DNA TOLERANCE (Plant adaptation to heavy metal and radioactive pollution)
Our objectives were to reveal mechanisms that affect genome stability in plants growing within the Chernobyl zone and in other anthropogenically contaminated places in Eurasia. Using morphological, physiological, proteomic, cellular, genetic and molecular approaches, we investigated how plants react to contamination, and how the genome is affected, damaged and repaired after treatment with genotoxins (heavy metals Cd2+ , Pb2+ , Ni+ and radiomimetics bleomycin and zeacin). The project utilised natural and induced variation from the model plants Arabidopsis and Physcomitrella, as well as selected annual and prennial crops that were grown in the zone.
Arabidopsis were either collected from “open-area laboratories” within the Chernobyl zone or obtained from the stock centres as accessions that had been previously collected from various locations worldwide. As a future resource, seeds from plants growing in the most and least contaminated areas of the Zone were geo-referenced to an updated map of radionuclide distribution. The geographical distribution of other A. thaliana genotypes was also mapped in relation to local pollution levels, where known. Primary root growth reactions to genotoxins and heavy metals were evaluated as part of genome wide association study and biparental mapping populations with novel accessions have been established to determine further the underlying genetic architecture affecting tolerance.
Multiple mechanisms were involved in stress tolerance and these can be spatially separated along the root. Furthermore, the stress imposed by different metals seems to act by different mechanisms, and may involve different response pathways. In some case, protectants have been identified and may have practical applications.
Effects of chronic radiation on the mutation rate in annual and woody plant species have been measured. Segregation distortion and mutation rates are positively correlated with contamination level. Also, fast growing populations of poplar and willow were developed for introduction into contaminated areas. A bioindicator index has been adapted for evaluation of ecosystem condition in radioactive areas of Ukraine and Russia
Quantitative changes in the proteome of developing seeds and of seedlings grown in radioactive and remediated Chernobyl areas were detected and selected proteins were examined for phosphorylation differences. Stress may lead to inheritable changes, which are passed through generations, possibly fixed by methylation patterns of gene coding regions or promoters. Grass varieties have been assessed for potential tolerance to heavy metals and their utility in remediation of contaminated soils in China has been assessed.
In summary, there are multiple mechanisms involving several molecular pathways associated with plant adaptation to adverse environments and long-lasting survival in contaminated environment. Genetic basis of stress tolerance and ability to grow crops on contaminated soils could provide a basis for breeding and biotechnological solutions for remediation of polluted areas and agricultural strategies for contaminated environments.
Arabidopsis were either collected from “open-area laboratories” within the Chernobyl zone or obtained from the stock centres as accessions that had been previously collected from various locations worldwide. As a future resource, seeds from plants growing in the most and least contaminated areas of the Zone were geo-referenced to an updated map of radionuclide distribution. The geographical distribution of other A. thaliana genotypes was also mapped in relation to local pollution levels, where known. Primary root growth reactions to genotoxins and heavy metals were evaluated as part of genome wide association study and biparental mapping populations with novel accessions have been established to determine further the underlying genetic architecture affecting tolerance.
Multiple mechanisms were involved in stress tolerance and these can be spatially separated along the root. Furthermore, the stress imposed by different metals seems to act by different mechanisms, and may involve different response pathways. In some case, protectants have been identified and may have practical applications.
Effects of chronic radiation on the mutation rate in annual and woody plant species have been measured. Segregation distortion and mutation rates are positively correlated with contamination level. Also, fast growing populations of poplar and willow were developed for introduction into contaminated areas. A bioindicator index has been adapted for evaluation of ecosystem condition in radioactive areas of Ukraine and Russia
Quantitative changes in the proteome of developing seeds and of seedlings grown in radioactive and remediated Chernobyl areas were detected and selected proteins were examined for phosphorylation differences. Stress may lead to inheritable changes, which are passed through generations, possibly fixed by methylation patterns of gene coding regions or promoters. Grass varieties have been assessed for potential tolerance to heavy metals and their utility in remediation of contaminated soils in China has been assessed.
In summary, there are multiple mechanisms involving several molecular pathways associated with plant adaptation to adverse environments and long-lasting survival in contaminated environment. Genetic basis of stress tolerance and ability to grow crops on contaminated soils could provide a basis for breeding and biotechnological solutions for remediation of polluted areas and agricultural strategies for contaminated environments.