Disentangling the influence of earthworms in sugarcane rhizosphere

Author(s)

Braga, Lucas P. P. ; Yoshiura, Caio A. ; Borges, Clovis D. ; Horn, Marcus A. ; Brown, George G. ; Drake, Harold L. ; Tsai, Siu M.

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 6, DEC 15 2016.
• Web of Science Citations: 4

Abstract

For the last 150 years many studies have shown the importance of earthworms for plant growth, but the exact mechanisms involved in the process are still poorly understood. Many important functions required for plant growth can be performed by soil microbes in the rhizosphere. To investigate earthworm influence on the rhizosphere microbial community, we performed a macrocosm experiment with and without Pontoscolex corethrurus (EW+ and EW-, respectively) and followed various soil and rhizosphere processes for 217 days with sugarcane. In EW+ treatments, N2O concentrations belowground (15 cm depth) and relative abundances of nitrous oxide genes (nosZ) were higher in bulk soil and rhizosphere, suggesting that soil microbes were able to consume earthworm-induced N2O. Shotgun sequencing (total DNA) revealed that around 70 microbial functions in bulk soil and rhizosphere differed between EW+ and EW- treatments. Overall, genes indicative of biosynthetic pathways and cell proliferation processes were enriched in EW+ treatments, suggesting a positive influence of worms. In EW+ rhizosphere, functions associated with plant-microbe symbiosis were enriched relative to EW- rhizosphere. Ecological networks inferred from the datasets revealed decreased niche diversification and increased keystone functions as an earthworm-derived effect. Plant biomass was improved in EW+ and worm population proliferated. (AU)

• FAPESP's process: 13/22845-2 - Interactions between sugarcane soil microbiota and earthworms on straw decomposition and emissions of greenhouse gases (GHG)
• Grantee: Lucas Palma Perez Braga
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/08564-6 - Molecular bioindicators of soil microbiome from corn crop under straw effect to N2O gas mitigation
• Grantee: Caio Augusto Yoshiura
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 11/51749-6 - Functional bioindicators for soil quality monitoring for sustainable management of sugarcane biomass production (BIOSQ)
• Grantee: Tsai Siu Mui
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants
• FAPESP's process: 15/11120-2 - TRACKING THE ROLE OF EARTHWORM-MICROBE INTERACTIONS ON BENEFICIAL FUNCTIONS IN SUGARCANE RHIZOSPHERE
• Grantee: Lucas Palma Perez Braga
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate