Comparative Analysis of the Chloroplast Genomes of Eight Species of the Genus Lirianthe Spach with Its Generic Delimitation Implications.

Based on Sima and Lu's system of the family Magnoliaceae, the genus Lirianthe Spach s. l. includes approximately 25 species, each with exceptional landscaping and horticultural or medical worth. Many of these plants are considered rare and are protected due to their endangered status. The limited knowledge of species within this genus and the absence of research on its chloroplast genome have greatly impeded studies on the relationship between its evolution and systematics. In this study, the chloroplast genomes of eight species from the genus Lirianthe were sequenced and analyzed, and their phylogenetic relationships with other genera of the family Magnoliaceae were also elucidated. The results showed that the chloroplast genome sizes of the eight Lirianthe species ranged from 159,548 to 159,833 bp. The genomes consisted of a large single-copy region, a small single-copy region, and a pair of inverted repeat sequences. The GC content was very similar across species. Gene annotation revealed that the chloroplast genomes contained 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes, totaling 130 genes. Codon usage analysis indicated that codon usage was highly conserved among the eight Lirianthe species. Repeat sequence analysis identified 42-49 microsatellite sequences, 16-18 tandem repeats, and 50 dispersed repeats, with microsatellite sequences being predominantly single-nucleotide repeats. DNA polymorphism analysis revealed 10 highly variable regions located in the large single-copy and small single-copy regions, among which rpl32-trnL, petA-psbJ, and trnH-psbA were the recommended candidate DNA barcodes for the genus Lirianthe species. The inverted repeat boundary regions show little variation between species and are generally conserved. The result of phylogenetic analysis confirmed that the genus Lirianthe s. l. is a monophyletic taxon and the most affinal to the genera, Talauma and Dugandiodendron, in Sima and Lu's system and revealed that the genus Lirianthe s. s. is paraphyletic and the genus Talauma s. l. polyphyletic in Xia's system, while Magnolia subsection Gwillimia is paraphyletic and subsection Blumiana polyphyletic in Figlar and Nooteboom's system. Morphological studies found noticeable differences between Lirianthe species in aspects including leaf indumentum, stipule scars, floral orientation, tepal number, tepal texture, and fruit dehiscence. In summary, this study elucidated the chloroplast genome evolution within Lirianthe and laid a foundation for further systematic and taxonomic research on this genus.

The complete chloroplast genome sequence of Michelia balansae var. balansae (Aug. Candolle) Dandy, a timber and spices species in Magnoliaceae.

Michelia balansae var. balansae (Aug. Candolle) Dandy is a timber and spices species in Magnoliaceae, native to China and Vietnam. In this paper, the complete chloroplast genome (cpDNA) and basic annotated information were reported and its phylogenetic relationship with other species in Magnoliaceae was analyzed. The size of chloroplast genome of M. balansae var. balansae is 160,134 bp, which exhibited a typical quadripartite structure comprising a large single-copy (LSC) region of 88,161 bp and a small single-copy (SSC) region of 18,845 bp separated by a pair identical inverted repeat regions (IRs) of 26,564 bp each. The chloroplast genome contains 131 genes, including 86 protein-coding genes (PCGs), 37 transfer RNA (tRNA) genes and 8 ribosomal RNA (rRNA) genes. The phylogenetic analysis indicated that M. balansae var. balansae is most affinal to M. montana and they form a nomophyletic group with other 14 Michelia species. This Michelia clade is sister to the Aromadendron clade with high support. All genera mentioned in this analysis are nomophyletic under the system of Magnoliaceae by Sima and Lu.

The complete chloroplast genome sequence of Lirianthe hodgsonii, a tree species of Magnoliaceae as least concern.

Lirianthe hodgsonii is a tree species of Magnoliaceae as least concern. In the present paper, the complete chloroplast genome (cpDNA) and basic annotated information of L. hodgsonii were reported and its phylogenetic relationship with other species in Magnoliaceae was analyzed. The size of its complete cpDNA is 159,693 bp, with a typical quadripartite structure comprising a pair of inverted repeat (IR) regions of 26,546 bp, a large single-copy (LSC) region of 87,848 bp and a small single-copy (SSC) region of 18,753 bp. The genome contains 131 unique genes, including 86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The phylogenetic analysis showed that L. hodgsonii is affinal to Lirianthe bidoupensis and they form a monophyletic group with other seven Lirianthe species. This Lirianthe clade is sister to the Dugandiodendron and Talauma clade with high support. All genera mentioned in this analysis are monophyletic under the system of Magnoliaceae by Sima and Lu.