Confirmation of hybrid origin in Arisaema (Araceae) using molecular markers

A population of hybrids between Arisaema triphyllum subsp. stewardsonii and A. dracontium was investigated using molecular markers to document the hybrid origin. Total genomic DNA was extracted from A. triphyllum, A. dracontium, and the hybrids, and subjected to sequence analysis of various regions of intergenic spacer and genes of chloroplast or intergenic spacer and genes of nuclear ribosome for single nucleotide polymorphisms (SNPs). Clustering was performed using the unweighted pair group method with averages (UPGMA) tested by bootstrap (BS). Hybrid origin could not be easily confirmed in some regions. However, dendrograms constructed with a combined sequence analysis of A. triphyllum 26S ribosomal RNA gene [sequence identification (SI) 467] plus A. tortuosum phytochrome C-like (phyC) gene (SI 468) were very similar to dendrograms constructed from sequences of all regions. This suggests that selecting SI 467 and SI 468 would be practical to identify hybrid origins involving two parental species. Clustering of hybrids together with the female parent in most target regions suggests that, in Arisaema, cpDNA is considered maternally inherited.

► This research investigated the putative A. triphyllum × A. dracontium hybrids using molecular markers generated from various target genes and regions of nuclear ribosomal (nr) and chloroplast cpDNA and to screen and select the most useful regions to confirm the hybrid origin.
► The dendrogram constructed by sequence analysis of A. triphyllum 26S ribosomal RNA gene (SI 467) plus of A. tortuosum phytochrome C-like (phyC) gene (SI 468) were very similar to that of all target regions.
► This suggests that selecting these two genes with an addition of A. nikoense var. australe chloroplast DNA intergenic spacer region (SI 464) would be practical and economical to identify hybrid origins between two parental species
► Further, clustering of the hybrid with female parent in a dendrogram constructed by chloroplast DNA target regions suggests that, in Arisaema, cpDNA is considered maternally inherited.