Despite its cultural and ecological significance, Phoebe bournei has experienced rapid population decline due to anthropogenic disturbances and climate change, leading to its “near threatened” status on the IUCN Red List. The species is highly sensitive to drought and climatic fluctuations, yet the genetic architecture underlying its climate adaptation has remained largely unexplored. Moreover, the reliance on limited genetic resources in plantations has undermined the tree’s environmental adaptability and recovery potential. Given these challenges, there is an urgent need to integrate genomic insights with predictive modeling to inform adaptive conservation strategies for this valuable species.
A team of researchers from Zhejiang A&F University and the Chinese Academy of Forestry has published (DOI: 10.1093/hr/uhag165) these findings in Horticulture Research, a journal of Oxford University Press, in 2026. The study represents the first genome‑wide investigation into the adaptive evolution of Phoebe bournei, providing a robust foundation for climate‑resilient management of this endangered tree.
The research team conducted whole‑genome resequencing of 362 individuals from 27 natural populations spanning the full distribution range of Phoebe bournei in China. Using two complementary genome‑environment association approaches—latent factor mixed model (LFMM) and redundancy analysis (RDA)—they identified 1,556 climate‑associated variants linked to 167 candidate genes responsive to temperature and precipitation variables. Among these, the gene TRX‑M4 (a chloroplast M‑type thioredoxin homolog) showed strong association with maximum temperature of the hottest month, with different alleles predominating in cooler versus warmer regions. Similarly, FBD1 (an F‑box family gene) was significantly associated with precipitation during the coldest quarter. Functional validation through yeast ectopic expression and quantitative PCR confirmed that these genes play integral roles in drought and heat stress responses. Notably, the adaptive variants were predominantly located in promoter and regulatory regions rather than protein‑coding sequences, suggesting that cis‑regulatory evolution—rather than changes to protein structure—is a key driver of climate adaptation in this species.
The authors said the findings highlight a dual regulatory strategy that helps the tree cope with environmental stress. “Promoter variants in genes like TRX‑M4 and FBD1 appear to fine‑tune the plant’s responses to temperature and water availability,” they explained. “One gene influences leaf morphology as a structural defense, while the other modulates shoot growth patterns to enable dynamic drought avoidance. This sophisticated integration of structural robustness and physiological plasticity is what allows the tree to navigate such heterogeneous climates.” They added that the southeastern populations, despite harbouring the highest genetic diversity, are projected to face the most severe genomic offset under future warming scenarios—meaning their current genetic makeup may no longer match the climates they will encounter.
The study’s predictive models, including the risk of non‑adaptedness (RONA) and gradient forest (GF) analyses, project that southeastern populations—particularly those in Zhejiang and Fujian provinces—will experience substantial climate‑driven adaptive pressure between 2041 and 2060. These populations, despite their elevated genetic diversity, appear most vulnerable to future temperature and precipitation extremes. The findings underscore the urgent need for genomics‑informed conservation strategies, including the establishment of comprehensive germplasm repositories covering the species’ entire geographic range and assisted migration programmes that introduce favourable genotypes from western populations adapted to warmer, drier conditions. Such measures could enhance climate resilience in the southeast while safeguarding existing genetic diversity.
###
References
DOI
10.1093/hr/uhag165
Original Source URL
https://doi.org/10.1093/hr/uhag165
Funding information
National Natural Science Foundation of China (Grant No. 32171828) and National Key R&D Program of China (2024YFD2200103).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.