Scientific progress: disproving previously-tenable hypotheses
Increasing organic yields: experience, not microbiomes?
Few gas-filled pathways into nodules
Nodule gas permeability: stomata-like mechanism?
Abundant soil nitrogen? Decrease nodule permeability
Insufficient symbiotic nitrogen? Decrease nodule permeability
Mixed-infection mutualism requires host sanctions
Improvements evolution missed? Cooperation, ecosystem organization
Improvements evolution missed? Seek acceptable tradeoffs
Population fluctuations explain reproduction/longevity tradeoffs
Forced eusociality makes rhizobia more beneficial
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