Plant landscape abundance and soil fungi modulate drought effects on plant–soil feedbacks
Plant landscape abundance and soil fungi modulate drought effects on plant–soil feedbacks
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DOI：
10.1111/oik.08836
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发表时间：
2022-05
期刊：
影响因子：
3.4
通讯作者：
Nianxun Xi;K. Crawford;Jonathan R. De Long
中科院分区：
文献类型：
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作者：
Nianxun Xi;K. Crawford;Jonathan R. De Long
植物-土壤反馈(PSF)在决定植物群落结构和动态中起着重要作用。然而，以前的研究对PSF和植物景观丰富度(即当地社区的丰富度)之间的关系提供了喜忧参半的结果。这可能反映了气候因素对PSF的中介作用。在这里，我们测试了树种的PSF如何随着当地丰度的变化而变化，通过在同种和异种土壤中生长幼苗，以及模拟干旱如何改变PSF与植物丰度的关系。选择了6个树种，其中一半的幼苗是在环境水分条件下生长的，而其他树种在环境水分条件下生长了3个月后，经历了2个月的干旱。利用DNA扩增序列分析了根际土壤中的真菌群落，以将土壤真菌的变化与观测到的PSF联系起来。我们发现，干旱降低了除一种(罗汉果)以外的所有植物的PSF为负。在干旱处理中，PSF与总病原菌的相对丰度呈正相关，而与独特病原菌的比例呈负相关(那些存在于同种土壤而不是异种土壤中的病原菌，因此具有潜在的种特异性)。此外，我们还发现，在干旱处理中，PSF只显著地预测了植物的相对丰富度，表明非生物胁迫使PSF成为一个更强的植物景观丰富度的预测因子。这一发现还表明，未来的极端干旱事件可能会促进丰富的植物物种的优势，从而导致生物多样性的丧失。总之，我们的结果为PSF的微生物机制提供了证据，并表明，由于自然条件下无处不在的胁迫，考虑非生物胁迫可以使PSF成为更强的植物景观丰富度预测因子。
Plant–soil feedbacks (PSF) play an important role in determining plant community structure and dynamics. However, previous studies have provided mixed results for the relationship between PSF and plant landscape abundance (i.e. abundance across local communities). This may reflect the mediation of climate factors on PSF. Here, we tested how PSF of tree species varied with local abundances by growing seedlings in conspecific versus heterospecific soil and how simulated drought altered PSF–plant abundance relationships. Six tree species were selected and half of the seedlings were grown under ambient moisture conditions, while the others experienced a 2‐month period of drought following 3‐months of growth under ambient moisture conditions. Fungal communities in the rhizosphere soil were analysed using DNA amplicon sequencing to link shifts in soil fungi to the observed PSF. We found that drought reduced negative PSF for all plant species except one species (Lithocarpus lohangwu). In the drought treatments, PSF were positively correlated with the relative abundance of total putative pathogens, but negatively correlated with the proportion of unique pathogens (those pathogens that were present in conspecific soil rather than heterospecific soil, thereby potentially species‐specific). In addition, we found that PSF only significantly predicted plant relative abundance in the drought treatment, indicating that abiotic stress made PSF a stronger predictor of plant landscape abundance. This finding also implies that future extreme drought events could promote the dominance of the abundant plant species, thereby leading to the loss of biodiversity. Collectively, our results provide evidence for microbial mechanisms of PSF and suggest that accounting for abiotic stress can make PSF a stronger predictor of plant landscape abundance due to the omnipresence of stress under natural conditions.