Two complete chloroplast genome sequences of genus Paulownia (Paulowniaceae): Paulownia coreana and P. tomentosa

The nucleotide sequence of the two chloroplast (cp) genomes from Paulownia coreana and P. tomentosa are the first to be completed in genus Paulownia of family Paulowniaceae. The structure of two Paulownia cp genomes shows similar characteristic with general cp genome of angiosperms. The lengths of two cp genomes are 154,545 bp and 154,540 bp, respectively. The cp genomes are divided into LSC region (85,241 bp and 85,236 bp) and SSC region (17,736 bp and 17,736 bp) by two IR regions (25,784 bp and 25,784 bp). Both of two cp genomes contain 113 genes (79 protein coding genes, 30 tRNA genes and 4 rRNA genes), eight protein-coding genes, seven tRNA genes and four rRNA genes duplicated in the IR regions. Similar to the general cp genome of angiosperms, 18 of the genes in the two cp genomes have one or two introns. The overall A-T contents of two genomes are 62.0% which is similar with general angiosperms. The A-T content in the non-coding (64.6%) is higher than in the coding (60.1%) regions. Seventy-one and seventy simple sequence repeat (SSR) loci were identified in the P. coreana and P. tomentosa cp genomes, respectively. In phylogenetic analysis, genus Paulownia shows closed relationship with Lindenbergia philippensis of Orobanchaceae.