Benning John W, Moeller David A
Department of Plant and Microbial Biology, University of Minnesota, 140 Gortner Labs, 1479 Gortner Avenue, Saint Paul, MN, 55108, USA.
New Phytol. 2021 Mar;229(5):2886-2900. doi: 10.1111/nph.17102. Epub 2020 Dec 18.
Interactions between plants and soil fungi and bacteria are ubiquitous and have large effects on individual plant fitness. However, the degree to which spatial variation in soil microbial communities modulates plant species' distributions remains largely untested. Using the California native plant Clarkia xantiana ssp. xantiana we paired glasshouse and field reciprocal transplants of plant populations and soils to test whether plant-microbe interactions affect the plant's geographic range limit and whether there is local adaptation between plants and soil microbe communities. In the field and glasshouse, one of the two range interior inocula had a positive effect on plant fitness. In the field, this benefit was especially pronounced at the range edge and beyond, suggesting possible mutualist limitation. In the glasshouse, soil inocula from beyond-range tended to increase plant growth, suggesting microbial enemy release beyond the range margin. Amplicon sequencing revealed stark variation in microbial communities across the range boundary. Plants dispersing beyond their range limit are likely to encounter novel microbial communities. In C. x. xantiana, our results suggest that range expansion may be facilitated by fewer pathogens, but could also be hindered by a lack of mutualists. Both negative and positive plant-microbe interactions will likely affect contemporary range shifts.
植物与土壤真菌和细菌之间的相互作用无处不在，对植物个体的适应性有很大影响。然而，土壤微生物群落的空间变异对植物物种分布的调节程度在很大程度上仍未得到验证。利用加利福尼亚本土植物黄花克拉花（Clarkia xantiana ssp. xantiana），我们将植物种群和土壤的温室与田间相互移栽配对，以测试植物 - 微生物相互作用是否影响植物的地理分布范围界限，以及植物与土壤微生物群落之间是否存在局部适应性。在田间和温室中，两个分布区内接种物之一对植物适应性有积极影响。在田间，这种益处在分布范围边缘及以外地区尤为明显，表明可能存在互利共生限制。在温室中，来自分布范围外的土壤接种物往往会促进植物生长，表明在分布范围边缘之外存在微生物敌人释放现象。扩增子测序揭示了分布范围边界上微生物群落的显著差异。扩散到其分布范围界限之外的植物可能会遇到新的微生物群落。在黄花克拉花中，我们的结果表明，分布范围的扩大可能因病原体减少而得到促进，但也可能因缺乏互利共生者而受到阻碍。植物与微生物之间的正负相互作用都可能影响当代的分布范围变化。
