Abstract Detail



Comparative Genomics/Transcriptomics

Choi, In-Su [1], Schwarz, Erika [2], Ruhlman, Tracey [1], Jansen, Robert [1].

Fluctuation in size and content of mitochondrial genomes across four subfamilies of Fabaceae.

Organelle genome studies of Fabaceae, an economically and evolutionarily important plant family, have been biased towards the plastid genome (plastome). Only eleven mitochondrial genome (mitogenome) sequences of Fabaceae have been published and nine of these are from the subfamily Papilionoideae, which has limited the understanding of mitogenomic size variation and content in the family. To resolve this, four mitogenomes were sequenced from three different subfamilies (Cercidoideae, Detarioideae, and Caesalpinioideae). Phylogenetic analysis based on shared mitochondrial protein coding regions produced a fully resolved and well-supported phylogeny that is completely congruent with the plastome tree. Comparative analysis suggests that two episodes of mitogenome expansion and contraction have occurred in Fabaceae. An ancient genome size expansion occurred subsequent to the divergence of the basal subfamily Cercidoideae, and is mainly caused by intercellular gene transfer (IGT) and/or interspecific horizontal gene transfer (HGT). The second, more recent expansion occurred in the Papilionoideae as a result of duplication of preexisting sequences. Family-wide gene content analysis revealed eleven gene losses, four (rps2, 7, 11, and 13) of which occurred in the ancestor of Fabaceae. Losses of remaining seven genes (cox2, rpl2, rpl10, rps1, rps19, sdh3, sdh4) are restricted to specific lineages or occurred independently in different clades. Introns of three genes (cox2, ccmFc, and rps10) showed extensive lineage-specific length variation due to large sequence insertions and deletions. Shared DNA analysis among Fabaceae mitogenomes demonstrated an exponential decay of intergenic spacers and provided further insight into HGT between the mimosoid clade of Caesalpinioideae and the holoparasitic Lophophytum (Balanophoraceae).


1 - University of Texas at Austin, Department of Integrative Biology, Austin, Texas, 78712, USA
2 - St. Edward’s University, Department of Biological Sciences, Austin, Texas, 78704, USA

Keywords:
Legumes
evolution
mt DNA
IGT
HGT.

Presentation Type: Poster This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PGT008
Abstract ID:357
Candidate for Awards:None


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