Chestnut plants (Castanea) are important nut fruit trees worldwide. However, little is known regarding the genetic relationship and evolutionary history of different species within the genus. How modern chestnut plants have developed local adaptation to various climates remains a mystery. The genomic data showed that Castanea henryi first diverged in the Oligocene at about 31.56 Million years ago, followed by Castanea mollissima, the divergence between Castanea seguinii and Castanea crenata in the mid-Miocene. Over the last 5 million years, the population of chestnut plants has continued to decline. A combination of selective sweep and environmental association studies was applied to investigate the genomic basis of chestnut adaptation to different climates. 22 candidate genes were associated with temperature and precipitation. We also revealed the molecular mechanism by which CmTOE1 interact with CmZFP8 and CmGIS3 to promote the formation of non-glandular trichomes for adaptation to low temperature and high altitudes. We found a significant expansion of CER1 genes in Chinese chestnut and verified the CmERF48 regulation of CmCER1.6 adaptation to drought environments. These results shed light on the East Asian chestnut plants as a monophyletic group that had completed interspecific differentiation in the Miocene and added candidate gene studies on adaptation to climate change for future studies in nut trees.

中文翻译：

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对东亚栗属进化和当地适应的新见解


板栗植物（Castanea）是世界范围内重要的坚果果树。然而，人们对该属内不同物种的遗传关系和进化历史知之甚少。现代板栗植物如何适应不同的气候仍然是一个谜。基因组数据显示，锥栗在约3156万年前的渐新世首次分化，随后在中新世中期出现了板栗（Castanea mollissima），即板栗和红栗的分化。在过去的五百万年里，板栗植物的数量持续减少。结合选择性扫描和环境关联研究来研究板栗适应不同气候的基因组基础。 22 个候选基因与温度和降水相关。我们还揭示了CmTOE1与CmZFP8和CmGIS3相互作用促进非腺毛形成以适应低温和高海拔的分子机制。我们发现板栗中CER1基因显着扩增，并验证了CmERF48对CmCER1.6适应干旱环境的调控。这些结果揭示了东亚板栗植物作为一个单系类群，在中新世完成了种间分化，并为未来坚果树的研究增加了适应气候变化的候选基因研究。