Changes in bulk soil affect the disease-suppressive rhizosphere microbiome against Fusarium wilt disease

Harnessing disease suppressive microbiomes constitutes a promising strategy for optimizing plant growth.However,relatively lttle information is available about the relationship between bulk and rhizosphere soil microbiomes.Here,the assembly of banana bulk soil and rhizosphere microbiomes was investigated in a mono-culture system consisting of bio-organic(BIO)and organic management practices.Applying BIO practice in newly reclaimed fields resulted in a high-efficiency biocontrol rate,thus providing a promising strategy for pre-control of Fusarium wilt disease.The soil microbiota was further characterized by MiSeq sequencing and quantitative PCR.The results indicate that disease suppression was mediated by the structure of a suppressive rhizosphere microbiome with respect to distinct community composition,diversity and abundance.Overall microbiome suppressiveness was primarily related to a particular set of enriched bacterial taxa affiliated with Pseudomonas,Terrimonas,Cupriavi-dus,Gp6,Ohtaekwangia and Duganella.Finally,struc-tural equation modeling was used to show that the changes in bulk soil bacterial community determined its induced rhizosphere bacterial community,which serves as an important and direct factor in restraining the pathogen.Collectively,this study provides an integrative approach to disentangle the biological basis of disease-suppressive microbiomes in the context of agricultural practice and soil management.

Soil metabolomics:Deciphering underground metabolic webs in terrestrial ecosystems

Soil metabolomics is an emerging approach for profiling diverse small molecule metabolites,i.e.,metabolomes,in the soil.Soil metabolites,including fatty acids,amino acids,lipids,organic acids,sugars,and volatile organic compounds,often contain essential nutrients such as nitrogen,phosphorus,and sulfur and are directly linked to soil biogeochemical cycles driven by soil microorganisms.This paper presents an overview of methods for analyzing soil metabolites and the state-of-the-art of soil metabolomics in relation to soil nutrient cycling.We describe important applications of metabolomics in studying soil carbon cycling and sequestration,and the response of soil organic pools to changing environmental conditions.This includes using metabolomics to provide new insights into the close relationships between soil microbiome and metabolome,as well as responses of soil metabolome to plant and environmental stresses such as soil contamination.We also highlight the advantage of using soil metabolomics to study the biogeochemical cycles of elements and suggest that future research needs to better understand factors driving soil function and health.