Root exudate composition can influence rhizosphere microbial recruitment and is tightly controlled by plant genetics. However, little research has profiled root exudate in vegetable crops or determined their role in rhizosphere microbial community and metabolite composition. It is also not well understood how root exudates and resulting rhizosphere dynamics shift across plant trait diversity and with the development of novel crop genotypes. To address these knowledge gaps, this study paired metabolomics and microbiome analyses to evaluate associations between the composition of exudates, soil bacterial and fungal communities, and soil metabolites across four genotypes of organically produced carrot of differential breeding histories, including two experimental genotypes. Plant genotypes modified soil microbial diversity and composition, and differentially recruited bacterial taxa. Bacterial rhizosphere recruitment from bulk soil was genotype and root exudate-mediated, while fungal recruitment was not. Moreover, root exudate composition was distinct in an heirloom genotype and a novel nematode resistant genotype, compared to other genotypes tested. Root exudate and rhizosphere metabolite composition was decoupled, and soil metabolites more strongly associated with fungal than bacterial communities. Taken together, the results of this study suggest that novel crop trait diversity and breeding histories hold consequences for the functional potential of soils through the diversification of root exudate mediated plant-microbe interactions.

中文翻译：

---

根系分泌物和根际微生物组装受到胡萝卜基因型中新植物性状多样性的影响


根系分泌物的成分可以影响根际微生物的补充，并受到植物遗传学的严格控制。然而，很少有研究对蔬菜作物的根系分泌物进行分析，或确定它们在根际微生物群落和代谢物组成中的作用。人们还不太清楚根系分泌物和由此产生的根际动态如何随着植物性状多样性和新作物基因型的发展而变化。为了解决这些知识差距，本研究将代谢组学和微生物组分析配对，以评估不同育种历史的有机生产胡萝卜的四种基因型（包括两种实验基因型）的渗出液组成、土壤细菌和真菌群落以及土壤代谢物之间的关联。植物基因型改变了土壤微生物的多样性和组成，并差异性地招募了细菌类群。从大块土壤中吸收的细菌根际是由基因型和根系分泌物介导的，而真菌的吸收则不是。此外，与测试的其他基因型相比，根分泌物成分在传家宝基因型和新型线虫抗性基因型中是不同的。根系分泌物和根际代谢物组成是解耦的，土壤代谢物与真菌的相关性比与细菌群落的相关性更强。总而言之，这项研究的结果表明，新的作物性状多样性和育种历史通过根系分泌物介导的植物-微生物相互作用的多样化，对土壤的功能潜力产生影响。