Abstract Detail

Phylogenomics

Cauz-Santos, Luiz Augusto [1], Dodsworth, Steven [2], Jakob, Aljaž [3], Samuel, Rosabelle [4], Paun, Ovidiu [3], Chase, Mark [5].

Phylogenomic relationships in Nicotiana benthamiana: insights into the origin of the N. benthamiana lab variant.

Nicotiana benthamiana is the most widespread Nicotiana species in Australia and an important model organism in the study of plant/virus interactions. The lab genotype has a loss of function mutation in the RNA-dependent RNA polymerase 1 (rdr1) gene, making it more susceptible to attack and therefore useful in the study of how viruses infect plants. The causal 72 bp insertion has now also been identified in several wild populations of N. benthamiana. However, there is still a lack of information on the origin, age and biogeography of N. benthamiana, particularly in relation to the laboratory variant. Nicotiana benthamiana is a member of N. sect. Suaveolentes, a group with an allopolyploid origin and variable ecology, including adaptation to the Australian deserts. Additionally, due to a recent and ongoing radiation in sect. Suaveolentes, standard phylogenetic markers have provided too little variation to explore phylogenetic relationships. To address some open questions in N. benthamiana origin and evolution, we used restriction site associated DNA sequencing (RADseq) to obtain a robust estimate of phylogenetic relationships and looked for evidence of hybridization using 36 accessions of N. benthamiana covering its range in tropical Australia and 28 accessions of other tropical species in N. sect. Suaveolentes. We obtained robust and well supported phylogenetic results with N. benthamiana sister to N. karijini and found that the laboratory variant is most similar to accessions from the northern Northern Territory and northeastern Kimberley, Western Australia. Furthermore, a coancestry map indicated evidence of hybridization in some accessions of N. benthamiana with N. forsteri, N. heterantha, and N. umbratica, which are sympatric with N. benthamiana in some areas. The results confirmed the potential of RADseq to explore phylogenetic relationships in this group and provided new evidence on the evolution of N. benthamiana that will be explored in future coalescent analyses.

1 - University of Vienna, Department of Botany and Biodiversity Research, Rennweg 14, Vienna, A-1030, Austria
2 - University of Bedfordshire, School of Life Sciences, University Square, Luton, Bedfordshire, LU1 3JU, UK
3 - University Of Vienna , Department Of Botany And Biodiversity Research, Rennweg 14, Vienna, A-1030, Austria
4 - University Of Vienna, Rennweg 14, Vienna, 9, 1030 Vienna, Austria
5 - Retired, 200 Richmond Road, Kingston, SRY, KT2 5HE, United Kingdom

Keywords:
Nicotiana benthamiana
model organism
phylogenomics
RADseq.

Presentation Type: Oral Paper
Session: PHYLOI, Phyogenomics I
Location: Virtual/Virtual
Date: Monday, July 19th, 2021
Time: 11:45 AM(EDT)
Number: PHYLOI008
Abstract ID:269
Candidate for Awards:None