|LI, XIAOGANG - Nanjing Forestry University|
|COLEMAN-DERR, DEVIN - University Of California|
|YAO, XIAODONG - Nanjing Forestry University|
|DING, CHANGFENG - Chinese Academy Of Sciences|
|WANG, XINGXIANG - Chinese Academy Of Sciences|
|DE BOER, WIETSE - Wageningen University|
Submitted to: Microbiome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2019
Publication Date: N/A
Interpretive Summary: Repeated planting of the same or closely-related crop species is a source of decreased performance and efficiency in conventional farming systems. Historically, this has often been attributed to an accumulation of plant disease organisms in the system over time. This work provides evidence in peanut that, rather than outright disease, these unfavorable side-effects of continuous cultivation are the product of a reduction in soil microbial diversity that limits beneficial soil organisms. This effect is not repeated in a rotated system. Comparing the microbial shifts between these systems highlights potential key players in the negative and beneficial effects the microbiome can have in a peanut cropping system.
Technical Abstract: Continuous monocropping often results in negative soil feedbacks, manifested as reduced plant performance. This is commonly attributed to accumulation of pathogenic organisms, but there is increasing evidence that other microbes also contribute. Here, we hypothesize that as bacterial microbiome displays discrepant preferences for root exudate profiles, monocropping will promote enrichment of a subset of bacterial species in the rhizosphere that negatively influence the performance of the crop. To test this, we examined soil feedbacks for peanut plants inoculated with bacterial suspensions obtained from monocropping and rotated plots in closed cultivation systems. 16S rRNA amplicon sequence analysis revealed significantly different effects of the bacterial suspension origins on the bacterial composition of peanut rhizospheres. Suspensions obtained from monocropped soils resulted in a significant reduction in species richness, as well as enrichment of select taxa including Sphingomonas sp., Herbaspirillum sp., and Arthrobacter sp. in peanut seedling rhizospheres. These point at a selective effect of peanut monocropping on rhizosphere community assembly, likely mediated by root exudation and rhizodeposition patterns. Bacterial inoculants from monocropped soil showed significantly deleterious effects on peanut traits (e.g., growth and physiological resistance) compared to rotated soil-derived inoculants. Taken together, our results suggest that continuous cropping induces enrichment of particular non-pathogenic bacterial taxa in the plant rhizosphere that lead to clear reductions in plant performance even in the absence of disease.