Biodiv Sci ›› 2021, Vol. 29 ›› Issue (10): 1308-1320.DOI: 10.17520/biods.2021057

• Original Papers: Plant Diversity • Previous Articles     Next Articles

Genome size variations and species differentiation of Reaumuria soongarica

Xingke Fan1,2, Xia Yan3, Yuanyuan Feng4, Jinhua Ran4, Chaoju Qian1, Xiaoyue Yin1,2, Shanshan Zhou1,2, Tingzhou Fang1,2, Xiaofei Ma1,3,*()   

  1. 1 Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000
    2 University of Chinese Academy of Sciences, Beijing 100049
    3 School of Life Sciences, Nantong University, Nantong, Jiangsu 226019
    4 State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093
  • Received:2021-02-09 Accepted:2021-06-10 Online:2021-10-20 Published:2021-10-20
  • Contact: Xiaofei Ma

Abstract:

Aims As a constructive shrub species widely distributed across the temperate deserts of arid Central Asia, Reaumuria soongarica (Tamaricaceae) had undergone divergence and hybridization during its evolutionary history, which make it an ideal model for understanding the molecular basis of biodiversity of desert ecosystems and plant hybrid speciation. However, the ploidy level of different populations of R. soongarica is still unclear, which confines the further study on its speciation mechanism.
Methods To clarify the ploidy level and variation patterns of genome size of different R. soongarica lineages, we investigated the DNA 1C-value of eight R. soongarica populations from the northern lineage (distributed in northern Xinjiang) and its putative parental lineages (the eastern and western lineages) by flow cytometry. The young roots of R. soongarica were selected as the experimental material, and Solanum pimpinellifolium was used as an internal standard species.
Results Our data showed that the DNA 1C-value of the eastern lineage (1.149 ± 0.012 pg) was slightly smaller than that of the western lineage (1.195 ± 0.031 pg), and the DNA 1C-value of the Fukang (FW) and Shawan (SW) populations in the northern lineage was intermediate between that of its parental lineages. However, the DNA 1C-values of the Huoshaoshan (HSS) and Wucaicheng (WCC) populations from the northern lineage were closely twice as those from the eastern and western populations.
Conclusion Considering to the previous results of molecular markers, we infer that the FW and SW populations belong to the homoploid hybrid populations from the eastern and western lineages, while the HSS and WCC populations are allopolyploid hybrid populations. The populations with different ploidy levels in the northern lineage could originate from different hybrid events, which could be classified into different species.

Key words: Reaumuria soongarica, DNA C-value, homoploid hybrid speciation, allopolyploid hybrid speciation, species diversity