Selective Pressure on Internal vs. External Immune Defence in Tribolium Castaneum - Experimental Evolution Using a Microsporidian and a Fungal Parasite

赤拟谷盗内部与外部免疫防御的选择压力 - 使用微孢子虫和真菌寄生虫的实验进化

• 批准号: 224777971
• 负责人: Dr. Gerrit Frauke Joop
• 金额: --
• 依托单位: Referat I B 3: Forschungsförderung
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/224777971?language=en
• 关键词: Selective; Pressure; Internal; vs.; External

Gaining a better understanding of immune defence and how it evolves is currently one of the most interesting topics in evolutionary biology. Moreover, the combination of evolutionary immunology with host parasite co-evolution will deepen our understanding even further, as it is taking immunology out of the nut shell and back to its natural conditions. This goes in line with the recent proclamation of the hologenome theory and the importance if microbiota.However, another until only recently neglected aspect of immune defence is the external immune defence in non-social organisms. External immune defence is an extended defence outside of the body, e.g. by behavioural changes or the secretion of antimicrobial compounds into the environment. Especially in the latter case, individuals not only act to their own benefit, but potentially also to the benefit of their offspring and of other group members. Furthermore, the external immune defence should interact with the internal immune defence to be sufficient.The Red Flour Beetle, Tribolium castaneum, secrets broadly antimicrobial substances into the flour environment, and therefore possesses such an external immune defence. In previous work it has been shown, that under natural conditions, i.e. a parasite containing environment, this external immune defence is in balance with the internal immune defence. Consequently, in the here proposed project I ask(1) whether the external immune defence is under selection by parasites, and if different parasites shift external and the classical internal immune defence in different directions.(2) how external and internal immune defences are balanced, and if selection by multiple parasites will result in disruption or stabilization of this balance.(3) how the balance between external and internal immune defence might be mediated, and if epigenetic effects impact on this.This will be addressed by experimental evolution of T. castaneum with a microsporidian (Paranosema whitei) and a fungal (Beauveria bassiana) parasite, in three different concentrations each as well as a combined parasite treatment. During this experiment external (quinone secretion) and internal (Phenoloxidase activity, cuticular darkness, inhibition of bacteria and fungi) immune parameter will be estimated on the phenotypic level. Experimental evolution will be followed by transcriptomic and epigenetic (looking at DNA methylation, histone acetylation/deacetylation, microRNAs) approaches to understand how this is mediated.Answering these questions will valuable insight into the evolution of immune defence strategies in an ecological context.

更好地理解免疫防御及其进化是目前进化生物学中最有趣的话题之一。此外，进化免疫学与宿主寄生虫共同进化的结合将进一步加深我们的理解，因为它使免疫学走出了坚果壳，回到了自然状态。这与最近宣布的全基因组理论和微生物群的重要性是一致的。然而，另一个直到最近才被忽视的免疫防御方面是非社会生物的外部免疫防御。外部免疫防御是一种在体外的延伸防御，例如通过行为改变或将抗菌化合物分泌到环境中。特别是在后一种情况下，个体不仅为自己的利益而行动，而且潜在地也为其后代和其他群体成员的利益而行动。此外，外部免疫防御必须与内部免疫防御相互作用才能充分。红粉甲虫（Tribolium castaneum）将大量抗菌物质秘密带入面粉环境，因此具有这种外部免疫防御。在以前的工作中已经表明，在自然条件下，即含有寄生虫的环境下，这种外部免疫防御与内部免疫防御是平衡的。因此，在这里提出的项目中，我要问(1)外部免疫防御是否受到寄生虫的选择，以及不同的寄生虫是否将外部和经典的内部免疫防御转向不同的方向。(2)外部和内部免疫防御是如何平衡的，多种寄生虫的选择是否会导致这种平衡的破坏或稳定。(3)外部免疫防御和内部免疫防御之间的平衡是如何介导的，以及表观遗传效应是否影响了这一平衡。这将通过用三种不同浓度的微孢子虫（白色Paranosema whitei）和真菌（白僵菌白僵菌Beauveria bassiana）寄生虫进行castaneum的实验进化以及寄生虫联合治疗来解决。在本实验中，将在表型水平上估计外部（醌分泌）和内部（酚氧化酶活性、表皮暗度、细菌和真菌抑制）的免疫参数。实验进化将遵循转录组学和表观遗传学（观察DNA甲基化，组蛋白乙酰化/去乙酰化，microrna）方法，以了解这是如何介导的。回答这些问题将对生态环境下免疫防御策略的演变有价值的见解。