RESEARCH ARTICLE
Complete chloroplast genomes of hemiparasitic genus Cymbaria : Insights into comparative analysis, development of molecular markers, and phylogenetic relationships
Yang Ma 1, Jordi López-Pujol 2, 3, Dongqing Yan 1, Zhen Zhou 1, Zekun Deng 1 and Jianming Niu 1, 4, 5
1 School of Ecology and Environment, Inner Mongolia University, Hohhot 010020, China
2 Botanic Institute of Barcelona (IBB), CSIC-Ajuntament de Barcelona, Barcelona 08038, Spain
3 Escuela de Ciencias Ambientales, Universidad Espíritu Santo (UEES), Samborondón 091650, Ecuador
4 Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Hohhot 010020, China
5 Inner Mongolia Key Laboratory of Grassland Ecology and the Candidate State Key Laboratory of Ministry of Science and Technology, Hohhot 010020, China
Correspondence
Jianming Niu, School of Ecology and Environment, Inner Mongolia University, Hohhot 010020, China; Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, Hohhot 010020, China; Inner Mongolia Key Laboratory of Grassland Ecology and the Candidate State Key Laboratory of Ministry of Science and Technology, Hohhot 010020, China
Email: 111964401@imu.edu.cn
Funding information
Major Science and Technology Projects of Inner Mongolia Autonomous Region, Grant/ Award Number: 2019ZD008; National Natural Science Foundation of China, Grant/ Award Number: 31860106 and 32260304
Abstract
Cymbaria L. is a small genus nearly endemic to the Mongolian Plateau with only two hemiparasitic species. Cymbaria daurica L. is an important herb “Xinba” in traditional Mongolian medicine. However, C. daurica is often confused with its sister speciesCymbaria mongolica Maxim. because they only differ in anther morphology. In addition, phylogenetic placement and reductive evolution of this genus within the Orobanchaceae remain poorly resolved. Here, we firstly sequenced two Cymbaria chloroplast genomes and then conducted a comparative analysis among those of 54 Orobanchaceae species. We found that the chloroplast genomes of Cymbariaspecies were characterized by pseudogenization/loss events of eightndh genes and a unique rbc L-mat K inversion. Unlike the high-variability observed in holoparasites, Cymbaria and other hemiparasites exhibited high similarity to autotrophs in genome size, GC content, and intact genes. Notely, four pairs of specific DNA barcodes (CymN1, CymN2, CymY, and CymR) were developed to distinguish the herb C. daurica from its adulterant C. mongolica . Phylogenetic analyses revealed that genus Cymbaria and theSchwalbea -Siphonostegia clade were grouped into the tribe Cymbarieae. This tribe formed an independent sister clade to the remaining parasitic lineages. Furthermore, the diversification of monophyletic Cymbaria occurred during the late Miocene (6.72 Mya) in the Mongol-Chinese steppe region. These findings provide valuable information for regarding taxonomy, phylogeny and evolution ofCymbaria and can be used to validate the authenticity of the herb “Xinba”.