Cooperation and coexpression: How coexpression networks shift in response to multiple mutualists.

Area of Science:

• Community ecology
• Molecular biology
• Systems biology

Background:

• Understanding community ecology necessitates studying nonadditive effects of multispecies interactions.
• Current research often focuses on pairwise interactions and single genes, limiting mechanistic insights.
• Multispecies symbioses involve complex ecological and molecular interactions.

Purpose of the Study:

• To investigate the impact of multispecies mutualisms on genomewide differential coexpression networks.
• To analyze the consequences of interactions between legume (Medicago truncatula), rhizobia, and mycorrhizal fungi.
• To identify key genes and network structures involved in these complex symbiotic relationships.

Main Methods:

• Analysis of genomewide differential coexpression networks in response to multiple mutualists.
• Comparative analysis of gene expression and network centrality for additive vs. nonadditive effects.
• Utilizing an "across-symbiosis" approach to identify context-specific gene coexpression.

Main Results:

• Genes affected nonadditively by multiple mutualists exhibit higher network connectivity and centrality.
• Multispecies mutualisms significantly rewire coexpression networks in both host plants and fungal symbionts.
• Altered coexpression structures by symbiotic interactions explain significant variation in plant performance.
• Identified unique coexpression patterns and coupled responses across symbiotic boundaries in a multispecies context.

Conclusions:

• Multispecies mutualisms profoundly influence molecular interactions within host plants and microbes.
• Nonadditive gene effects are critical players in transcriptomic responses to complex symbioses.
• Rewiring of molecular networks by third-party mutualists highlights the interconnectedness of symbiotic systems.
• This study provides a foundation for understanding the molecular basis of multispecies interactions in ecological communities.