Phylogenetic relationships in the "true citrus fruit trees" revealed by PCR-RFLP analysis of cpDNA

The PCR-RFLP analysis of chloroplast DNA was performed to assess the phylogenetic relationships in 30 accessions of "true citrus fruit trees" (Citrinae, Rutaceae) including 6 Fortunella spp., 1 Eremocitrus sp., 2 forms of Poncirus sp., 1 Clymenia sp., 5 Microcitrus spp. and 16 Citrus spp. The four amplified regions of cpDNA; rbcL-ORF106, psaA-trnS, trnH-trnK and trnD-trnT were analyzed with 15 restriction enzymes. Of 140 fragments scored, 108 were polymorphic. A phylogenetic tree was constructed with UPGMA cluster analysis of the distance matrix. All of Microcitrus species were differentiated from each other as well as from other species. Eremocitrus was placed within Microcitrus cluster but had clearly different cpDNA patterns from the Microcitrus species. While Clymenia, Fortunella and Poncirus formed independent groups, respectively, these three genera were closer to Citrus than to Microcitrus and Eremocitrus. Citrus species were divided into three main clusters. Maternal origins of some Citrus species were discussed. (C) 2004 Elsevier B.V. All rights reserved.