Despite its cultural and ecological significance, Phoebe bournei has experienced rapid population decline due to anthropogenic disturbances and climate change, leading to its \u201cnear threatened\u201d 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\u2019s 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.<\/p>\n
A team of researchers from Zhejiang A&F University and the Chinese Academy of Forestry has published (DOI: 10.1093\/hr\/uhag165)<\/a> these findings in Horticulture Research<\/a>, a journal of Oxford University Press, in 2026. The study represents the first genome\u2011wide investigation into the adaptive evolution of Phoebe bournei, providing a robust foundation for climate\u2011resilient management of this endangered tree.<\/p>\n The research team conducted whole\u2011genome resequencing of 362 individuals from 27 natural populations spanning the full distribution range of Phoebe bournei in China. Using two complementary genome\u2011environment association approaches\u2014latent factor mixed model (LFMM) and redundancy analysis (RDA)\u2014they identified 1,556 climate\u2011associated variants linked to 167 candidate genes responsive to temperature and precipitation variables. Among these, the gene TRX\u2011M4 (a chloroplast M\u2011type 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\u2011box 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\u2011coding sequences, suggesting that cis\u2011regulatory evolution\u2014rather than changes to protein structure\u2014is a key driver of climate adaptation in this species.<\/p>\n The authors said the findings highlight a dual regulatory strategy that helps the tree cope with environmental stress. \u201cPromoter variants in genes like TRX\u2011M4 and FBD1 appear to fine\u2011tune the plant\u2019s responses to temperature and water availability,\u201d they explained. \u201cOne 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.\u201d 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\u2014meaning their current genetic makeup may no longer match the climates they will encounter.<\/p>\n The study\u2019s predictive models, including the risk of non\u2011adaptedness (RONA) and gradient forest (GF) analyses, project that southeastern populations\u2014particularly those in Zhejiang and Fujian provinces\u2014will experience substantial climate\u2011driven 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\u2011informed conservation strategies, including the establishment of comprehensive germplasm repositories covering the species\u2019 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.<\/p>\n ###<\/p>\n References<\/p>\n DOI<\/p>\n 10.1093\/hr\/uhag165 <\/a><\/p>\n Original Source URL<\/p>\n https:\/\/doi.org\/10.1093\/hr\/uhag165 <\/a><\/p>\n Funding information<\/p>\n National Natural Science Foundation of China (Grant No. 32171828) and National Key R&D Program of China (2024YFD2200103).<\/p>\n