School of Biological Sciences, Monash University, Clayton, Victoria, Australia.
The University of Sydney, Charles Perkins Centre and School of Life and Environmental Sciences, Sydney, Australia.
PLoS Genet. 2023 Feb 13;19(2):e1010635. doi: 10.1371/journal.pgen.1010635. eCollection 2023 Feb.
Dietary nutrient composition is essential for shaping important fitness traits and behaviours. Many organisms are protein limited, and for Drosophila melanogaster this limitation manifests at the level of the single most limiting essential Amino Acid (AA) in the diet. The identity of this AA and its effects on female fecundity is readily predictable by a procedure called exome matching in which the sum of AAs encoded by a consumer's exome is used to predict the relative proportion of AAs required in its diet. However, the exome matching calculation does not weight AA contributions to the overall profile by protein size or expression. Here, we update the exome matching calculation to include these weightings. Surprisingly, although nearly half of the transcriptome is differentially expressed when comparing male and female flies, we found that creating transcriptome-weighted exome matched diets for each sex did not enhance their fecundity over that supported by exome matching alone. These data indicate that while organisms may require different amounts of dietary protein across conditions, the relative proportion of the constituent AAs remains constant. Interestingly, we also found that exome matched AA profiles are generally conserved across taxa and that the composition of these profiles might be explained by energetic and elemental limitations on microbial AA synthesis. Thus, it appears that ecological constraints amongst autotrophs shape the relative proportion of AAs that are available across trophic levels and that this constrains biomass composition.
饮食营养成分对于塑造重要的健康特征和行为至关重要。许多生物体受到蛋白质的限制，对于黑腹果蝇来说，这种限制表现在饮食中单个最限制必需氨基酸（AA）的水平上。通过一种称为外显子匹配的程序，可以很容易地预测这种 AA 的身份及其对雌性生育力的影响，在外显子匹配中，消费者外显子编码的 AA 总和用于预测其饮食中所需 AA 的相对比例。然而，外显子匹配计算并没有根据蛋白质大小或表达来对 AA 对整体谱的贡献进行加权。在这里，我们更新了外显子匹配计算，以包括这些权重。令人惊讶的是，尽管在比较雌雄蝇时近一半的转录组差异表达，但我们发现，为每一种性别创建转录组加权的外显子匹配饮食并不能提高它们的生育能力超过仅外显子匹配所支持的生育能力。这些数据表明，尽管生物体在不同条件下可能需要不同量的膳食蛋白质，但组成 AA 的相对比例保持不变。有趣的是，我们还发现，外显子匹配的 AA 谱在分类群中通常是保守的，并且这些谱的组成可能可以通过微生物 AA 合成的能量和元素限制来解释。因此，似乎自养生物之间的生态限制塑造了跨营养水平可用的 AA 的相对比例，从而限制了生物量的组成。
