The alfalfa leafcutting bee, Megachile rotundata is widely used in the western United States as a pollinator for alfalfa seed production. Unfortunately, immatures experience high mortality in agriculturally managed populations. Quantified gene expression could be used to identify how this bee responds during different life stages to pathogens, environmental toxins, and other stresses, but stably expressed reference genes are needed to normalize transcription data. We evaluated twelve candidate genes for their transcription stability across different life stages, including during and after diapause. RPS18 and RPL8 were the two most stably expressed genes, followed by RPS5 and RPL27A. These genes were also very stable even during and after diapause, while the most variable genes being APN, PMIIM, NPC2, and Cr-PII had increased expression levels during larval growth and were also variable during and after diapause. The four reference genes we identified in M. rotundata may prove useful for transcriptomic studies in other bees as well, such as honey bees.

中文翻译：

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蜜蜂Megachile rotundata生命周期中参考基因表达的变化

苜蓿切叶蜜蜂Megachile rotundata在美国西部被广泛用作苜蓿种子生产的传粉媒介。不幸的是，未成年人在农业管理的人口中死亡率很高。量化的基因表达可用于鉴定蜜蜂在不同生命阶段对病原体，环境毒素和其他胁迫的反应，但是需要稳定表达的参考基因来标准化转录数据。我们评估了十二种候选基因在不同生命阶段（包括滞育期间和滞育后）的转录稳定性。RPS18和RPL8是两个最稳定表达的基因，其次是RPS5和RPL27A。这些基因即使在滞育期间和滞育后也非常稳定，而变化最大的基因是APN，PMIIM，NPC2，Cr-PII和Cr-PII在幼虫生长期间表达水平增加，并且在滞育期间和滞后也存在差异。我们在中鉴定出的四个参考基因rotundata分支杆菌也可能被证明可用于其他蜜蜂（如蜜蜂）的转录组研究。