Polymorphism of chloroplast DNA in citrus

Abstract

Chloroplast DNA (cpDNA) diversity was studied in Citrus, Poncirus and Fortunella, based on restriction fragment length polymorphism (RFLP). Total genomic DNA was digested with restriction endonucleases singly or in combination, Southern blotted, and hybridized with a Nicotiana tabacum cpDNA probe. According to the fragment patterns, Citrus was divided into four groups : mandarin/citron, pummelo, Yuzu, and lime. The fragment patterns of mandarin/citron group (mandarin, citron and tangor) differed from those of pummelo group (pummelo, sweet orange, sour orange, lemon, grapefruit, Kunenbo, Hassaku, Natsudaidai, Sudachi, Hyuganatsu and Iyo) in Pst I, Pst I/Pvu II, Pst I/Kpn 1 and Pst 1/Sac I digestion. The fragment patterns of lime were identical to pummelo group in Pst I and Pst I/Sac I digestion, but differed in Pst I/Pvu II and Pst I/Kpn I digestion. Yuzu was not distinguishable from mandarin/citron group in the fragment patterns of Pst 1/, Pst I/Pvu II and Pst I/Kpn 1 digestion, but was distinguishable in that of Pst I/Sac I digestion. The fragment patterns of Poncirus and Fortunella were always identical to those of mandarin/citron group.