Subjects: Biology >> Botany >> Applied botany submitted time 2023-12-24 Cooperative journals: 《广西植物》
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.
Subjects: Biology >> Botany >> Applied botany submitted time 2020-01-12 Cooperative journals: 《广西植物》
Abstract：石山苣苔属（苦苣苔科）约41种，主要分布于我国西南石灰岩地区。目前为止，仅其中四种的染色体数目被研究和报道，其余绝大多数物种的染色体数目和倍性尚不清楚，染色体数目和倍性在该属及其姐妹属报春苣苔属中的演变历史及其对两属物种多样性分化的影响亦不清楚。该文以叶片水培生根法获取的四种（含一变种）石山苣苔属植物[即石山苣苔原变种(Petrocodon dealbatus var. dealbatus)、齿缘石山苣苔(Petrocodon dealbatus var. denticulatus)、弄岗石山苣苔(Petrocodon longangensis)、石山苣苔未定名种(Petrocodon sp.)的根尖细胞为实验材料开展染色体实验，探索了多种不同的实验条件对染色体制片效果的影响并获取染色体数目，然后在石山苣苔属和报春苣苔属系统树上追踪了染色体数目和倍性的演变历史，并探讨染色体数目尤其倍性变化是否对两属物种多样性分化存在影响。结果表明：长度为1~1.5 cm的根尖，0.002 mol·L-1 8-羟基喹啉溶液预处理5 h，解离4 min为较适宜的染色体制备条件；四种（含一变种）石山苣苔属植物染色体数目一致，均为二倍体（2n=2x=36）；两属之间及两属各自的最近共同祖先染色体数目尚不能确定，除个别物种染色体条数或倍性有变化外，其余已知染色体数目的物种均为2n=2x=36，在两属中高度一致；石山苣苔属与报春苣苔属物种多样性分化尤其两属物种多样性巨大差异与染色体数目和基因组倍性变化无关。本研究可为石山苣苔属植物及其近缘类群染色体制备提供参考，也为进一步对该类群的分类、系统演化和物种形成等方面的研究提供基础数据和启示。
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