Quercus acutissima (sawtooth oak) is a dominant species occupying a wide range of environmental conditions in subtropical and warm temperate zones in China. Owing to its high ecological and economic value, it has been listed as a precious timber species in China. Populations of this species can persist across large temperature and precipitation ranges. However, the genetic‐based climate adaptation in Q. acutissima remains unclear.
In a study published in Journal of Systematics & Evolution, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) combined a common garden experiment with range‐wide population genomics analyses to infer the demographic history and characterize patterns of local adaptation in the sawtooth oak.
The researchers surveyed approximately 8% of the oak genome and recovered 55？361 single nucleotide polymorphisms (SNPs) from sampled populations of Q. acutissima. Those sites included a balanced proportion of both genic and non‐coding regions. Genetic structure and principal component analysis of these populations indicated an east‐west split.
Coalescent‐based model simulations inferred a late Pleistocene divergence in Q. acutissima between the east and west groups as well as subsequent preglaciation population expansion events.
Moreover, the genetic and phenotypic analyses revealed a joint effect of geography and environment on Q. acutissima.
“To our knowledge, this study is the first to attempt to combine a genome scan and phenotype evaluation in a common garden in an Asian subtropical oak species; it will provide a valuable study system to compare with temperate oaks in North America and Europe”, said Dr. GAO Jie, first author of the study.
The approach, which combined a common garden experiment with landscape genomics data, validated the hypothesis of local adaptation of the long‐lived oak tree of subtropical China.
GAO Jie Ph.D
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China