Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan.
NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo 156-8502, Japan.
Cell Rep. 2019 Sep 3;28(10):2594-2607.e7. doi: 10.1016/j.celrep.2019.08.030.
During evolution, organisms have acquired variable feeding habits. Some species are nutritional generalists that adapt to various food resources, while others are specialists, feeding on specific resources. However, much remains to be discovered about how generalists adapt to diversified diets. We find that larvae of the generalists Drosophila melanogaster and D. simulans develop on three diets with different nutrient balances, whereas specialists D. sechellia and D. elegans cannot develop on carbohydrate-rich diets. The generalist D. melanogaster downregulates the expression of diverse metabolic genes systemically by transforming growth factor β (TGF-β)/Activin signaling, maintains metabolic homeostasis, and successfully adapts to the diets. In contrast, the specialist D. sechellia expresses those metabolic genes at higher levels and accumulates various metabolites on the carbohydrate-rich diet, culminating in reduced adaptation. Phenotypic similarities and differences strongly suggest that the robust carbohydrate-responsive regulatory systems are evolutionarily retained through genome-environment interactions in the generalists and contribute to their nutritional adaptabilities.
在进化过程中，生物获得了可变的饮食习惯。有些物种是营养上的通才，能够适应各种食物资源，而有些则是专门针对特定资源的专家。然而，关于通才如何适应多样化的饮食，仍有许多需要发现。我们发现，营养通才果蝇（Drosophila melanogaster）和拟暗果蝇（D. simulans）的幼虫可以在三种营养平衡不同的饮食中生长，而专家果蝇（D. sechellia）和秀丽隐杆线虫（D. elegans）则不能在富含碳水化合物的饮食中生长。营养通才果蝇通过转化生长因子β（TGF-β）/激活素信号通路系统地下调多种代谢基因的表达，维持代谢平衡，并成功适应这些饮食。相比之下，专家果蝇（D. sechellia）在富含碳水化合物的饮食中表达这些代谢基因的水平更高，并积累了各种代谢物，最终导致适应性降低。表型上的相似性和差异性强烈表明，通过基因组-环境相互作用，在营养通才中保留了强大的碳水化合物反应性调节系统，这有助于它们的营养适应性。
