Chloroplast genome capture history and genetic diversity of Camellia sinensis var. sinensis cv. ‘Liupao’

Subjects: Biology >> Botany >> Applied botany submitted time 2023-12-24 Cooperative journals: 《广西植物》

YAO Shuting ZHANG Qiang SU Min WU Yuting PANG Yuelan LIANG Yanni CAI Aihua QIN Xinmei

Abstract： Camellia sinensis var. sinensis cv. ‘Liupao’ is the main raw material for making Liupao tea. To explore the genetic background of C. sinensis var. sinensis cv. ‘Liupao’, especially its phylogenetic position and evolutionary history, 27 and five individuals of C. sinensis var. sinensis cv. ‘Liupao’ and C. costata were sampled for genome skimming and transcriptomic sequencing. The phylogenetic relationship between C. sinensis var. sinensis cv. ‘Liupao’ and other Camellia was reconstructed, the divergence time of the chloroplast genome sequences of C. sinensis var. sinensis cv. ‘Liupao’ was estimated, and the genetic diversity was investigated. The results were as follows: (1) On the chloroplast tree, 27 samples of C. sinensis var. sinensis cv. ‘Liupao’ were divided into two distantly-related groups, one was nested within a clade mainly consisting of C. sinensis, being interspersed among other cultivated C. sinensis, while the other group formed as a well supported lineage that was most closely-related to and nested within C. costata; On the nuclear gene tree, however, all the 27 samples formed a clade with other C. sinensis as well as some other Camellia species with generally unresolved relationships among them. Despite the lack of resolution in this clade, it was definitely far separated from C. costata; The cytonuclear phylogenetic conflict suggested once ancient introgression hybridization of C. costata with the ancestor of some C. sinensis var. sinensis cv. ‘Liupao’ individuals so that the latter captured the chloroplast genome of the former. (2) The time estimate indicated that the introgression hybridization event occurred in the Quaternary period, ca. 1.55 million years ago, long before the history of tea cultivation and production by humans. (3) In addition, both the chloroplast genomes and nuclear genes revealed that the C. sinensis var. sinensis cv. ‘Liupao’ had high haplotype diversity, possessing high evolutionary potential. This study could provide important references for the germplasm protection, breeding, and utilization of high-quality C. sinensis var. sinensis cv. ‘Liupao’ strains.

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