ARS | Publication request: Nitrate Reductase Phylogeny of Potato (Solanum sect. Petota) Genomes with Emphasis on the Origins of the Polyploid Species

Submitted to: Systematic Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 2008
Publication Date: February 5, 2009
Citation: Rodriguez, F., Spooner, D.M. 2009. Nitrate Reductase Phylogeny of Potato (Solanum sect. Petota) Genomes with Emphasis on the Origins of the Polyploid Species. Systematic Botany. 34:207-219.

Interpretive Summary: There are about 190 species of wild potatoes. An understanding of their interrelationships aids breeders and genebank managers, but an understanding of these interrelationships presently is known mainly from a limited number of sources. Namely, most data comes from morphology (the outward appearance of the plant) and molecular data from plant organelles called plastids. This study uses another data source, DNA from the nucleus of the plant, to compare to these other data sets, through a gene region technically called nitrate reductase. This nuclear gene region is particularly useful because it is able to better show relationships of the polyploid species (species having more than one set of chromosomes). The results largely support the plastid DNA results but with some minor differences. However, they are particularly useful in showing origins of the polyploids from different sets of unrelated diploid species. These results will aid breeders in understanding the genetic composition of these polyploid species.

Technical Abstract: Solanum section Petota is taxonomically difficult, partly because of interspecific hybridization at both the diploid and polyploid levels. There is much disagreement regarding species boundaries and affiliation of species to series. Elucidating the phylogenetic relationships within the polyploids is crucial for an effective taxonomic treatment of the section and for the utilization of wild potato germplasm in breeding programs. We here infer relationships among the potato diploids and polyploids using nitrate reductase (NIA) sequence data in comparison to prior plastid phylogenies and: 1) infer genomes within section Petota, 2) show species in the polyploid series Conicibaccata, Longipedicellata, and in the Iopetalum group to be derived from allopolyploidization, 3) support an earlier hypothesis by confirming S. verrucosum as the maternal genome donor for the polyploid species S. demissum and species in the Iopetalum Group, 4) demonstrate that S. verrucosum is the maternal genome donor for species in ser. Longipedicellata, 5) support S. acaule as a segmental allotetraploid, and 6) show the North and Central American B genome species to be well distinguished from the A genome species of South America.