ИСТИНА

Lotus comprises ca. 130 species of Old World herbs, semishrubs and shrubs, including important pasture crops and a model legume, L. japonicus. Earlier nrITS-based phylogenies were incongruent with all taxonomic classifications of the genus. In particular, members of the former genus Dorycnium were unexpectedly placed near species of L. sect. Lotus. We present a global phylogenetic study of Lotus that uses both plastid (psbA-trnH IGS and rps16 intron) and nuclear (ITS and ETS) markers. The rooting of the Lotus phylogeny, its major clades and basic biogeographic patterns are discussed. The placement of the segregate genera Dorycnium and Tetragonolobus in the synonymy of Lotus was confirmed. Analyses of plastid data strongly supported a basal split of Lotus into two clades, one comprising species of sect. Lotus plus those traditionally placed in Dorycnium and the other including the rest of the species. The former clade has a centre of species diversity in Europe and N Asia, and the latter in Macaronesia, Africa and S Asia. Only the “Southern” clade is resolved in analyses of nrITS and nrETS data. Trees inferred from plastid, nrITS and nrETS data shared the occurrence of several smaller clades corresponding to traditionally recognized infrageneric taxa or species groups as well as the occurrence of some well-supported clades that differ from traditional taxonomic concepts. Several instances of incongruence were documented between nuclear and plastid markers and between the two nuclear markers, possibly resulting from reticulate evolution. The extant geographic patterns of Lotus are likely biased by at least one round of area fragmentation followed by expansion coupled with extensive speciation associated with the complex history of the Mediterranean biome. Lotus corniculatus complex that belongs to the section Lotus is the most agriculturally important, but taxonomically problematic group of the genus. The presence of at least two ploidy levels and interspecific hybridization confuses the system of the group. Phylogenetic relationships among L. corniculatus complex and other groups of the section Lotus vary in reconstructions inferred from different DNA markers. However, all studies clearly demonstrate a highly supported monophyly of the L. corniculatus complex. Phylogenetic analysis of the section Lotus using trnF-L IGS and trnL intron of cpDNA revealed taxonomic significance of indels in these DNA regions. A haplotype network of the L. corniculatus complex constructed using statistical parsimony method in TCS program allowed to make the following suggestions concerning phylogeography of the group: we revealed a specimen of uncertain morphology with a haplotype related to Lotus conimbricensis (the closest relative of the L. corniculatus complex), which may shed light on the origin of the complex; a haplotype from one of West European glacial refugia (Systema Central, Spain) found in L. alpinus is the closest to a hypothetical ancestral haplotype of the L. corniculatus complex; derived haplotypes were spreading eastward from W. Europe and gave two peaks of diversity: high in C. and E. Europe and a smaller one in Asian part of Northern Eurasia. The origin of East African and Japanese lineages of the complex is also discussed.