Abstract (eng)
Nicotiana sect. Suaveolentesis a paleopolyploid section, native to Australia, Africa and the South Pacific. This group is suitable for studying longer-term effects triggered by whole genome doubling. The group is around 6mil years old,and it is expected to have had an ancestral chromosome number n = 24. As a result of chromosomal rearrangements and loss of DNA, at present the species of the group have a series of chromosome reductions with between 24 and 15 chromosome pairs. The species in this section show also variable ecologies, including some with adaptations to harsh, extreme habitats in the central Australian deserts. The group contains Nicotiana benthamiana, a useful and important model organism much used in plant virology and biotechnology. Nicotiana benthamiana has a wide geographical distribution, and morphological and immunological diversity. The natural origin of the lab line is near the Granites Gold Mine in the Northern Territory, Australia. In this study, phylogenetic relationships were investigated for260 accessions of 47 described and undescribed taxa, and additionally population structure and biogeography of N. benthamiana were explored using restriction site associated DNA sequencing (RADseq) data, making use of an available reference genome of N. benthamiana. The resulting phylogenetic tree is robust and well supported, providing a good framework for future study of post-allopolyploidization chromosomal evolution and adaptation to extreme habitats. Nicotiana benthamiana was found to have four geographical subpopulations. The laboratory strain was found to be closely related to the two accessions from Judbarra/Gregory National Park in the Northern Territory