Do cisgenic plants warrant less stringent oversight?
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Food Technology↗
Biomedical subjects
Henk J Schouten
Publications and source records attributed to Henk J Schouten.
Cisgenic plants are similar to traditionally bred plants: international regulations for genetically modified organisms should be altered to exempt cisgenesis.
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Breeding↗
Validation of the high-throughput marker technology DArT using the model plant Arabidopsis thaliana.
Diversity Arrays Technology (DArT) is a microarray-based DNA marker technique for genome-wide discovery and genotyping of genetic variation. DArT allows simultaneous scoring of hundreds of restriction site based polymorphisms between genotypes and does not require DNA sequence information or site-specific oligonucleotides. This paper demonstrates the potential of DArT for genetic mapping by validating the quality and molecular basis of the markers, using the model plant Arabidopsis thaliana. Restriction fragments from a genomic representation of the ecotype Landsberg erecta (Ler) were amplified by PCR, individualized by cloning and spotted onto glass slides. The arrays were then hybridized with labeled genomic representations of the ecotypes Columbia (Col) and Ler and of individuals from an F(2) population obtained from a Col x Ler cross. The scoring of markers with specialized software was highly reproducible and 107 markers could unambiguously be ordered on a genetic linkage map. The marker order on the genetic linkage map coincided with the order on the DNA sequence map. Sequencing of the Ler markers and alignment with the available Col genome sequence confirmed that the polymorphism in DArT markers is largely a result of restriction site polymorphisms.
Arabidopsis↗
Quantification of allele-specific expression of a gene encoding strawberry polygalacturonase-inhibiting protein (PGIP) using Pyrosequencing.
Recent studies indicate that allele-specific differences in gene expression are a common phenomenon. The extent to which differential allelic expression exists might be underestimated, due to the limited accuracy of the methods used so far. To demonstrate allele-specific expression, we investigated the transcript abundance of six individual, highly homologous alleles of a polygalacturonase-inhibiting protein gene (FaPGIP) from octoploid strawberry (Fragaria x ananassa). We applied the highly quantitative Pyrosequencing method which, for the gene under study, detected allele frequency differences as small as 4.0 +/- 2.8%. Pyrosequencing of RT-PCR products showed that one FaPGIP allele was preferentially expressed in leaf tissue, while two other alleles were expressed in a fruit-specific way. For fruits that were inoculated with Botrytis cinerea a strong increase in overall FaPGIP gene expression was observed. This upregulation was accompanied by a significant change in FaPGIP allele frequencies when compared with non-treated fruits. Remarkably, in the five cultivars tested, the allele frequency in cDNA from the inoculated fruits was similar to that in genomic DNA, suggesting uniform upregulation of all FaPGIP alleles present as a result of pathogenesis-related stress. The results demonstrate that when Pyrosequencing of RT-PCR products is performed, novel allele-specific gene regulation can be detected and quantified.
Alleles↗
Fitness effects of Alternaria dauci on wild carrot in The Netherlands.
In a field experiment with a susceptible population of annual wild carrot (Daucus carota) from Iran, artificial inoculations with the fungal pathogen A. dauci led to a strong and very significant increase of the diseased leaf area. The pathogen caused a very significant decrease in fecundity and seed survival of the host. This considerable fitness reduction by A. dauci would suggest that introgression of disease resistance from cultivated (transgenic) carrot cultivars into wild carrot populations could strongly increase the fitness of wild carrot. In spite of the potential ability of A. dauci to lower the fitness of the host considerably, wild carrot is very common in The Netherlands. Disease levels of wild carrot were estimated in 26 natural populations in 1998. No A. dauci could be detected on the leaves, and only 0.4% of the seeds were contaminated with A. dauci, in spite of the conducive weather for A. dauci. Resistance tests showed that all 26 monitored populations were highly resistant to A. dauci strains from The Netherlands. It is probable that the strong potential fitness reduction by A. dauci led to a high selection pressure towards resistance in The Netherlands. In conclusion, our results suggest that transgenic resistance to A. dauci would not be beneficial to wild carrot populations in The Netherlands because they are already resistant to this pathogen.
Alternaria↗