Plant–soil feedback (PSF), regulated by both mycorrhizae and soil-borne pathogens, is a primary mechanism maintaining high tree species diversity in the tropics. But how warming actually affects PSF is not well understood. We conducted a field warming experiment to test PSF on seedling mortality of two tree species: a rhizobia-associated tree (Ormosia semicastrata, Fabaceae) suffering from host-specific soil-borne pathogens and an ectomycorrhizal fungi-associated tree (Cyclobalanopsis patelliormis, Fagaceae) with low susceptibility to soil-borne pathogens. Soil fungi from the warming versus control seedling plots were identified by molecular sequencing. Results showed that the elevated temperature lowered seedling mortality of O. semicastrata, but had no effect on C. patelliormis seedlings. This indicates that warming weakened the negative PSF on O. semicastrata, presumably due to the observed decrease of the relative abundance of plant-pathogenic fungi and increase of ectomycorrhizal fungi but did not affect the PSF on C. patelliormis. The differential warming effects on seedling mortality of species with different microbial associations affords an example showcasing how the change in soil-borne microbes in response to global warming would, in turn, through PSF, alter tropical tree species composition and diversity. This study helps shed mechanistic light on the debate of biodiversity change as driven by climate change.

中文翻译：

---

变暖改变土壤微生物群落和热带树木幼苗死亡率

受菌根和土传病原体调节的植物-土壤反馈 (PSF) 是维持热带地区高树种多样性的主要机制。但变暖实际上如何影响 PSF 尚不清楚。我们进行了田间变暖实验，以测试 PSF 对两种树种幼苗死亡率的影响：一种与根瘤菌相关的树（红豆属 semicastrata，豆科）和一种外生菌根真菌相关的树（青冈菜，壳斗科）对土传病原体的敏感性低。通过分子测序鉴定了来自变暖和对照幼苗地块的土壤真菌。结果表明，升高的温度降低了O. semicastrata的幼苗死亡率，但对C. patelliormis幼苗没有影响。这表明升温削弱了O. semicastrata的负 PSF ，这可能是由于观察到植物病原真菌相对丰度的减少和外生菌根真菌的增加，但并未影响C. patelliormis的 PSF 。变暖对具有不同微生物关联的物种的幼苗死亡率的不同影响提供了一个例子，展示了土壤传播的微生物响应全球变暖的变化如何反过来通过 PSF 改变热带树种的组成和多样性。这项研究有助于从机制上阐明气候变化驱动的生物多样性变化的争论。