Structural Diversities and Phylogenetic Signals in Plastomes of the Early-Divergent Angiosperms: A Case Study in Saxifragales
Shiyun Han,
Hengwu Ding,
De Bi,
Sijia Zhang,
Ran Yi,
Jinming Gao,
Jianke Yang,
Yuanxin Ye,
Longhua Wu,
Xianzhao Kan
Affiliations
Shiyun Han
Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
Hengwu Ding
Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
De Bi
College of Landscape Engineering, Suzhou Polytechnic Institute of Agriculture, Suzhou 215000, China
Sijia Zhang
Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
Ran Yi
Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
Jinming Gao
Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
Jianke Yang
Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
Yuanxin Ye
Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
Longhua Wu
CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
Xianzhao Kan
Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
As representative of the early-divergent groups of angiosperms, Saxifragales is extremely divergent in morphology, comprising 15 families. Within this order, our previous case studies observed significant structural diversities among the plastomes of several lineages, suggesting a possible role in elucidating their deep phylogenetic relationships. Here, we collected 208 available plastomes from 11 constituent families to explore the evolutionary patterns among Saxifragales. With thorough comparisons, the losses of two genes and three introns were found in several groups. Notably, 432 indel events have been observed from the introns of all 17 plastomic intron-containing genes, which could well play an important role in family barcoding. Moreover, numerous heterogeneities and strong intrafamilial phylogenetic implications were revealed in pttRNA (plastomic tRNA) structures, and the unique structural patterns were also determined for five families. Most importantly, based on the well-supported phylogenetic trees, evident phylogenetic signals were detected in combinations with the identified pttRNAs features and intron indels, demonstrating abundant lineage-specific characteristics for Saxifragales. Collectively, the results reported here could not only provide a deeper understanding into the evolutionary patterns of Saxifragales, but also provide a case study for exploring the plastome evolution at a high taxonomic level of angiosperms.
