engleski

Characterization of the novo induced polyploid Dalmatian pyrethrum (Tanacetum cinerariifolium)

Dalmatian pyrethrum (Tanacetum cinerariifolium) is a perennial herb native to Croatia known for the production of insecticidal chemicals known as pyrethrins. Pyrethrum was one of the few natural insecticides before the era of synthetic insecticides. In order to increase pyrethrin yield, we created polypoid pyrethrum by chromosome doubling and subsequent crossing. Tetraploid, triploid, mixoploid and aneuploid plants were recovered and their ploidy level confirmed by karyotyping and ow cytometry. Tetraploid and triploid plants were morphometrically compared showing the 3n plants being more vigorous. A substantial diference in stomata size between 2n, 3n and 4n plants was detected. Furthermore, pollen viability and germination was lower in polyploid plants. FISH analysis with two subterminal satellite DNA families, TcSAT1 and TcSAT2, as probes showed lower variability in number of subtelomeric signals in 3n and 4n plants in comparison to 2n plants. Meiosis in polyploid pollen mother cells showed chromosome pairing that result in formation of chromosome con_gurations from univalents to multivalents. Increased number of multivalents indicated potentially increased activity of homologous recombination (HR) proteins. In order to support this finding, we analysed the expression of T.cinerariifolium genes involved in HR. By analyzing the published T. cinerariifolium transcriptome, we identified several Tanacetum orthologs of these genes. Their expression profiles in diploid and polyploid pyrethrum will be presented. In addition, we will present diploid and polyploid expression profiles of several pyrethrin biosynthesis genes, as well as our preliminary data of pyrethrin concentrations in diploid and polyploid plants.

Tanacetum cinerariifolium ; meiosis ; polyploidy ; pyrethin ; recombination ; subtelomeric repeats

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