关键词: 桉属, 叶绿体DNA, rpl2-trnH, trnH-psbA, 鉴定, DNA条形码

Abstract: In this study, sequences of trnH-psbA spacer were analyzed for 13 Eucalyptus samples. The trnH-psbA spacer of 13 Eucalyptus samples varied in length from 538 to 576 bp, and were aligned with a consensus length of 590 bp. Fifty-two mutationswere scored in total. Six of these characterswere indels, and 46
characterswere substitution. The chloroplast genome of Eucalyptus, like that of most angiosperms, possesses inverted repeats ( IR). The rpl2-trnH spacer, located at one of two junctions between the IRs and the large single copy (LSC) regions, was also sequenced from 11 Eucalyptus DNA samples. equences of rpl2-trnH were 79 - 149 bp in size, and were aligned with a consensus length of 154 bp. Nineteen mutations were scored in total. Four of these characterswere indels. When compared with E. urophylla, only one mutation was observed in the rpl2-trnH spacer sequences of the elite clone ( GL4 ). However, compared with E.grand is and E. grandis ×E. urophylla, GL4 possessed a relatively large ( 27 bp ) insertion in trnH-psbA intergenic spacer. Moreover, the sequences of rpl2-trnH among these four related samples show single-site mutations ( 12 in total). Extensive variation was found in the rpl2-trnH and trnH-psbA intergenic spacer( IGS) regions, suggesting that the sequences in this pair of loci have the potential to discriminate among the
largest number of species or varieties of eucalypt for DNA barcoding purposes.

Key words: Eucalyptus, chloroplast DNA, rpl2-trnH, trnH-psbA, identification, DNA barcoding