Phylogenetic implications of chloroplast DNA restriction site variation in subtribes Raphaninae and Cakilinae (Brassicaceae, tribe Brassiceae)

Abstract

Chloroplast DNA restriction site data was used to assess relationships among 41 taxa of the subtribes Raphaninae and Cakilinae (tribe Brassiceae, Brassicaceae). A total of 456 restriction site mutations was observed, with 237 (52%) being phylogenetically informative. Cladistic analysis, based on Wagner parsimony analysis, indicated four major clades: (i) CAKILE, (ii) CRAMBE, (iii) NIGRA lineage, and (iv) RAPA-OLERACEA lineage. The CAKILE clade was divided into two lineages: (i) Cakile, Erucaria (including Reboudia), and Didesmus (previously assigned by Schulz to the Raphaninae) and (ii) Crambella (previously assigned by Schulz to the Raphaninae). The Raphaninae as currently circumscribed is polyphyletic in origin. The cpDNA data supported separate subtribal status for Crambe (Raphaninae) and indicated two major lineages corresponding to sect. Dendrocrambe and the combined sections Crambe and Leptocrambe. Enarthrocarpus arcuatus, Enarthrocarpus lyratus, Morisia monanthos, Raphanus raphanistrum, Raphanus sativus, and Rapistrum perenne were included in the RAPA-OLERACEA lineage of subtribe Brassicinae. Ceratocnemum rapistroides, Cordylocarpus muricatus, Guiraoa arvensis, Hemicrambe fruticulosa, Kremeriella cordylocarpus, Muricaria prostrata, Otocarpus virgatus, Raffenaldia primuloides, and Rapistrum rugosum were included in the NIGRA lineage of subtribe Brassicinae. Key words: Brassicinae, Raphaninae, Cakilinae, chloroplast DNA restriction site variation, molecular systematics.