Berens Ali J, Hunt James H, Toth Amy L
Program in Bioinformatics and Computational Biology, Iowa State University, Ames, IA, 50011, USA.
Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.
BMC Genomics. 2015 Mar 25;16(1):235. doi: 10.1186/s12864-015-1410-y.
Social insects exhibit striking phenotypic plasticity in the form of distinct reproductive (queen) and non-reproductive (worker) castes, which are typically driven by differences in the environment during early development. Nutritional environment and nourishment during development has been shown to be broadly associated with caste determination across social insect taxa such as bees, wasps, and termites. In primitively social insects such as Polistes paper wasps, caste remains flexible throughout adulthood, but there is evidence that nourishment inequalities can bias caste development with workers receiving limited nourishment compared to queens. Dominance and vibrational signaling are behaviors that have also been linked to caste differences in paper wasps, suggesting that a combination of nourishment and social factors may drive caste determination. To better understand the molecular basis of nutritional effects on caste determination, we used RNA-sequencing to investigate the gene expression changes in response to proteinaceous nourishment deprivation in Polistes metricus larvae.
We identified 285 nourishment-responsive transcripts, many of which are related to lipid metabolism and oxidation-reduction activity. Via comparisons to previously identified caste-related genes, we found that nourishment restriction only partially biased wasp gene expression patterns toward worker caste-like traits, which supports the notion that nourishment, in conjunction with social environment, is a determinant of developmental caste bias. In addition, we conducted cross-species comparisons of nourishment-responsive genes, and uncovered largely lineage-specific gene expression changes, suggesting few shared nourishment-responsive genes across taxa.
Overall, the results from this study highlight the complex and multifactorial nature of environmental effects on the gene expression patterns underlying plastic phenotypes.
社会性昆虫以独特的生殖型（蚁后）和非生殖型（工蚁）等级表现出显著的表型可塑性，这通常由早期发育期间环境的差异所驱动。发育过程中的营养环境和营养状况已被证明与蜜蜂、黄蜂和白蚁等社会性昆虫类群的等级决定广泛相关。在诸如黄胡蜂等原始社会性昆虫中，等级在整个成年期都保持灵活，但有证据表明，与蚁后相比，工蚁获得的营养有限，营养不平等会使等级发育产生偏差。支配行为和振动信号也是与黄胡蜂等级差异相关的行为，这表明营养和社会因素的组合可能驱动等级决定。为了更好地理解营养对等级决定影响的分子基础，我们使用RNA测序来研究黄胡蜂幼虫对蛋白质营养剥夺的基因表达变化。
我们鉴定出285个对营养有反应的转录本，其中许多与脂质代谢和氧化还原活性有关。通过与先前鉴定的与等级相关的基因进行比较，我们发现营养限制仅部分地使黄蜂的基因表达模式偏向于工蚁等级样特征，这支持了营养与社会环境共同作用是发育等级偏差决定因素的观点。此外，我们对营养反应基因进行了跨物种比较，发现基因表达变化在很大程度上具有谱系特异性，这表明不同类群之间几乎没有共享的营养反应基因。
总体而言，本研究结果突出了环境对可塑性表型潜在基因表达模式影响的复杂性和多因素性质。
