Identification of plastid genotypes in Oenothera subsect. Munzia by restriction fragment length polymorphisms (RFLPs)

Abstract

Five discrete plastid genotypes (plastomes), designated I–V and typified by Oenothera Hookeri, biennis, Lamarckiana, parviflora and argillicola respectively, have been previously characterized within the European subsect. Euoenothera. The evolutionarily more-derived plastome types (I, II and V) are generally less tolerant of new hybridization events than the ancestral types (III and IV), and were first identified based on their incompatibility reactions with standard hybrid nuclei. Restriction maps for all five plastomes are available for the enzymes PvuII, SalI, KpnI and PstI (Gordon et al. 1982). The present study employs PvuII and KpnI restriction digests to compare 28 of the 45 species of subsect. Munzia with Euoenothera plastomes I–V. The results of plastome RFLP fingerprinting show uniform divergence of the South American taxa from their European congeners; all share the previously documented 45-kb inversion in the large single-copy region reported by Hachtel et al. (1991). However, at least six new plastome types have evolved within subsect. Munzia, giving rise to small-fragment size differences of 0.1–0.7 kb. In two of these cases (Oe. featherstonei and Oe. longiflora) unique fragments occurred. For Oe. featherstonei the unique KpnI fragment resulted from a novel 2.2 kb insertion, whereas in Oe. longiflora an additional PvuII restriction site has been created.