Bacterial cross-feeding data

Nutritional interdependence is widespread within microbial communities. However, co-inoculation of most auxotrophic microorganisms often fails to establish stable metabolite exchange relationship. We used lysine and arginine auxotrophic Escherichia coli genotypes to examined their interactions over 25 days. Our results indicate that co-inoculation renders both amino acid production and utilization of auxotrophs unstable. We found that one strain (ΔL) consistently outcompeted the other (ΔA) due to faster metabolic responses. ΔL cells exhibited lysine utilization positively correlated with lysine production by ΔA, stabilizing their population size despite fluctuating lysine supply from ΔA. Conversely, ΔA individuals lack this metabolic pattern, resulting in the ΔL population exploiting the ΔA population. These findings highlight that metabolic asymmetries and specific utilization patterns destabilize microbial syntrophy. Our work underscores the importance of balanced metabolic exchanges for developing sustainable synthetic microbial consortia and offers insights into the evolutionary dynamics of microbial cooperation.

微生物群落内部普遍存在营养互依现象。然而，对多数营养缺陷型微生物进行共接种时，往往难以建立稳定的代谢物交换关系。我们采用赖氨酸与精氨酸营养缺陷型大肠杆菌（Escherichia coli）基因型菌株，开展了为期25天的相互作用研究。研究结果表明，共接种会导致营养缺陷型菌株的氨基酸产生与利用过程均不稳定。我们发现，其中一株菌株（ΔL）始终比另一株（ΔA）更具竞争优势，这源于其更快的代谢响应速度。ΔL菌株的赖氨酸利用情况与ΔA菌株产生的赖氨酸含量呈正相关，即便ΔA菌株的赖氨酸供应存在波动，该菌株的种群规模仍可保持稳定。与之相反，ΔA菌株个体并不具备这种代谢模式，最终导致ΔL种群对ΔA种群形成剥削。上述研究结果凸显了代谢不对称性与特定利用模式会破坏微生物互生共营关系的稳定性。本研究强调了平衡代谢交换对于构建可持续合成微生物群落的重要性，并为微生物合作的进化动力学研究提供了新见解。