The complete chloroplast genome sequence of Xylia xylocarpa

The first complete chloroplast genome (cpDNA) sequence of Xylia xylocarpa was determined from Illumina HiSeq pair-end sequencing data in this study. The cpDNA is 161,288 bp in length, contains a large single copy region (LSC) of 89,186 bp and a small single copy region (SSC) of 19,354 bp, which were separated by a pair of inverted repeats (IR) regions of 26,370 bp. The genome contains 131 genes, including 86 protein-coding genes, eight ribosomal RNA genes, and 37 transfer RNA genes. The overall GC content of the whole genome is 36.6%, and the corresponding values of the LSC, SSC, and IR regions are 34.1%, 30.8%, and 42.8%, respectively. Further phylogenomic analysis showed that X. xylocarpa clustered in a unique clade in Caesalpinioideae subfamily

The complete chloroplast genome sequence of Fosbergia shweliensis, an endemic species to Yunnan of China

The first complete chloroplast genome (cpDNA) sequence of Fosbergia shweliensis was determined from Illumina HiSeq pair-end sequencing data in this study. The cpDNA is 154,717 bp in length, contains a large single-copy region (LSC) of 84,747 bp and a small single-copy region (SSC) of 18,230 bp, which were separated by a pair of inverted repeats (IR) regions of 25,870 bp. The genome contains 130 genes, including 85 protein-coding genes, 8 ribosomal RNA genes, and 36 transfer RNA genes. Further phylogenomic analysis showed that F. shweliensis was close to Coffea genus in the family Rubiaceae

The complete chloroplast genome sequence of Taxus yunnanensis

The first complete chloroplast genome (cpDNA) sequence of Taxus yunnanensis was determined from Illumina HiSeq pair-end sequencing data in this study. The cpDNA is 129,190 bp in length. Like other species of taxus genus, the chloroplast genome of T. yunnanensis has lost one of the large inverted repeats (IRs). The genome contains 116 genes, including 82 protein-coding genes, 4 ribosomal RNA genes, and 30 transfer RNA genes. Further phylogenomic analysis showed that T. yunnanensis closed to T. brevifolia in Lauraceae family

Transcriptome and comparative chloroplast genome analysis of Taxus yunnanensis individuals with high and low paclitaxel yield

Paclitaxel is a potent anti-cancer drug that is mainly produced through semi-synthesis, which still requires plant materials as precursors. The content of paclitaxel and 10-deacetyl baccatin III (10-DAB) in Taxus yunnanensis has been found to differ from that of other Taxus species, but there is little research on the mechanism underlying the variation in paclitaxel content in T. yunnanensis of different provenances. In this experiment, the contents of taxoids and precursors in twigs between a high paclitaxel-yielding individual (TG) and a low paclitaxel-yielding individual (TD) of T. yunnanensis were compared, and comparative analyses of transcriptomes as well as chloroplast genomes were performed. High-performance liquid chromatography (HPLC) detection showed that 10-DAB and baccatin III contents in TG were 18 and 47 times those in TD, respectively. Transcriptomic analysis results indicated that genes encoding key enzymes in the paclitaxel biosynthesis pathway, such as taxane 10-β-hydroxylase (T10βH), 10-deacetylbaccatin III 10-O-acetyltransferase (DBAT), and debenzoyl paclitaxel N-benzoyl transferase (DBTNBT), exhibited higher expression levels in TG. Additionally, qRT-PCR showed that the relative expression level of T10βH and DBAT in TG were 29 and 13 times those in TD, respectively. In addition, six putative transcription factors were identified that may be involved in paclitaxel biosynthesis from transcriptome data. Comparative analysis of plastid genomes showed that the TD chloroplast contained a duplicate of rps12, leading to a longer plastid genome length in TD relative to TG. Fifteen mutation hotspot regions were identified between the two plastid genomes that can serve as candidate DNA barcodes for identifying high-paclitaxel-yield individuals. This experiment provides insight into the difference in paclitaxel accumulation among different provenances of T. yunnanensis individuals