Data from: Transcriptional markers of sub-optimal nutrition in developing Apis mellifera nurse workers

Background: Honey bees (Apis mellifera) contribute substantially to the worldwide economy and ecosystem health as pollinators. Pollen is essential to the bee’s diet, providing protein, lipids, and micronutrients. The dramatic shifts in physiology, anatomy, and behavior that accompany normal worker development are highly plastic and recent work demonstrates that development, particularly the transition from nurse to foraging roles, is greatly impacted by diet. However, the role that diet plays in the developmental transition of newly eclosed bees to nurse workers is poorly understood. To further understand honey bee nutrition and the role of diet in nurse development, we used a high-throughput screen of the transcriptome of 3 day and 8 day old worker bees fed either honey and stored pollen (rich diet) or honey alone (poor diet) within the hive. We employed a three factor (age, diet, age x diet) analysis of the transcriptome to determine whether diet affected nurse worker physiology and whether poor diet altered the developmental processes normally associated with aging. Results: Substantial changes in gene expression occurred due to starvation. Diet-induced changes in gene transcription occurring in younger bees were largely a subset of those occurring in older bees, but certain signatures of starvation were only evident 8 day old workers. Of the 18,542 annotated genes in the A. mellifera genome, 0.7% (126 genes) exhibited differential expression due to poor diet at 3d of age compared with 81% (15,001 genes) that differed due to poor diet at 8d of age. Of the genes that were differentially expressed in young or old pollen deprived bees, poor diet caused more frequent down-regulation of gene expression in younger bees compared to older bees. In addition, the age-related physiological changes that accompanied early adult development differed due to the diet these young adult bees were fed. More frequent down-regulation of gene expression was observed in developing bees fed a poor diet compared to an adequate diet. Functional analyses also show that the physiological and developmental processes occurring in well-fed bees are vastly different than those occurring in pollen deprived bees. These data support the hypothesis that poor diet causes normal age-related development to go awry. Conclusion: Poor nutrition has major consequences for the expression of genes underlying the physiology and age-related development of nurse worker bees. More work is certainly needed to fully understand the consequences of starvation and the complex biology of nutrition and development in this system, but the genes identified in the present study provide a starting point for understanding the consequences of poor diet and for mitigating the economic costs of colony starvation.研究背景：作为传粉媒介，西方蜜蜂（Apis mellifera）对全球经济与生态系统健康均具有重要贡献。花粉是蜜蜂膳食的核心组成，可为其提供蛋白质、脂质与微量营养素。正常工蜂发育过程中伴随的生理、解剖结构与行为模式的剧烈变化具有高度可塑性，近期研究表明，发育进程（尤其是从保育蜂到采集蜂的职能转变）极易受膳食的影响。然而，关于膳食在新羽化蜜蜂向保育工蜂发育转变过程中所发挥的作用，目前仍知之甚少。为深入探究蜜蜂营养机制以及膳食在保育蜂发育中的作用，本研究对蜂箱内分别饲喂蜂蜜+贮藏花粉（丰裕膳食）与仅饲喂蜂蜜（匮乏膳食）的3日龄、8日龄工蜂的转录组（transcriptome）进行了高通量筛选。本研究采用三因素（日龄、膳食、日龄×膳食）分析方法对转录组数据进行处理，旨在明确膳食是否会影响保育工蜂的生理状态，以及匮乏膳食是否会改变正常衰老相关的发育进程。 研究结果：饥饿会引发基因表达的显著改变。幼年蜜蜂中膳食诱导的基因转录变化，在很大程度上属于成年蜜蜂相关变化的子集，但部分饥饿相关的表达特征仅在8日龄工蜂中显现。在西方蜜蜂基因组的18542个注释基因中，3日龄时因膳食匮乏出现差异表达（differential expression）的基因占比为0.7%（共126个），而8日龄时该占比则达到81%（共15001个）。在花粉剥夺处理的幼年或成年工蜂的差异表达基因中，与成年工蜂相比，幼年蜜蜂因膳食匮乏出现基因表达下调的频率更高。此外，幼年成虫发育伴随的年龄相关生理变化，会因饲喂膳食的不同而存在差异。与饲喂充足膳食的发育工蜂相比，饲喂匮乏膳食的发育工蜂中基因表达下调的发生频率更高。功能富集分析结果同样显示，饲喂充足膳食的工蜂与花粉剥夺处理工蜂的生理与发育进程存在显著差异。本研究数据支持“匮乏膳食会打乱正常年龄相关发育进程”这一假说。 研究结论：营养匮乏会对保育工蜂生理及年龄相关发育相关的基因表达产生重大影响。尽管仍需开展更多研究以全面阐明该系统中饥饿的影响以及营养与发育的复杂生物学机制，但本研究鉴定得到的基因可为理解膳食匮乏的影响、减轻蜂群饥饿带来的经济损失提供研究起点。