Sunflower spines and beyond: Mechanisms and breadth of pollen that reduce gut pathogen infection in the common eastern bumble bee
Sunflower spines and beyond: Mechanisms and breadth of pollen that reduce gut pathogen infection in the common eastern bumble bee
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DOI：
10.1111/1365-2435.14320
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发表时间：
2023-04-04
影响因子：
5.2
通讯作者：
Adler, Lynn S.
中科院分区：
文献类型：
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作者：
Figueroa, Laura L.;Fowler, Alison;Adler, Lynn S.
1. 植物具有独特的化学和物理特性，能够减少从灵长类动物到毛虫等动物的感染。向日葵（菊科向日葵属）就是一个显著的例子，其花粉能够抑制东方大黄蜂（熊蜂属）肠道中的锥虫病原体克氏锥虫的感染。然而，这种效应背后的机制一直难以捉摸，而且我们不知道其他菊科植物的花粉是否有类似的作用。
2. 我们评估了介导向日葵花粉抗病原体作用的机制是物理的（由于其带刺的花粉外壁）、化学的（由于代谢物）还是两者兼而有之。我们还评估了其他七种菊科植物的花粉相对于向日葵花粉和两种非菊科植物的花粉对克氏锥虫感染的抑制程度，以及花粉刺的长度是否能预测对病原体的抑制作用。
3. 我们发现，仅向日葵花粉外壁就与整个向日葵花粉一样有效地减少了感染，而向日葵花粉的代谢物则没有这种作用。此外，喂食其他七种菊科植物中四种植物花粉的蜜蜂，其克氏锥虫感染率比喂食非菊科植物花粉的蜜蜂低62% - 92%。然而，刺的长度并不能解释大黄蜂感染的差异。
4. 我们的研究表明，向日葵花粉抑制克氏锥虫的能力是由其带刺的花粉外壁驱动的，而且这种现象也延伸到其他几种菊科植物。我们的研究结果表明，向日葵花粉外壁在减少感染方面与整个花粉一样有效，这表明未来的研究应该扩展到评估其他具有带刺花粉的物种对传粉者 - 病原体动态的影响。
1. Plants have unique chemical and physical traits that can reduce infections in animals ranging from primates to caterpillars. Sunflowers (Helianthus annuus; Asteraceae) are one striking example, with pollen that suppresses infections by the trypanosomatid gut pathogen Crithidia bombi in the common eastern bumble bee (Bombus impatiens). However, the mechanism underlying this effect has remained elusive, and we do not know whether pollens from other Asteraceae species have similar effects.2. We evaluated whether mechanisms mediating sunflower pollen's antipathogenic effects are physical (due to its spiny exine), chemical (due to metabolites) or both. We also evaluated the degree to which pollen from seven other Asteraceae species reduced C. bombi infection relative to pollen from sunflower and two non-Asteraceae species, and whether pollen spine length predicted pathogen suppression.3. We found that sunflower exines alone reduced infection as effectively as whole sunflower pollen, while sunflower pollen metabolites did not. Furthermore, bees fed pollen from four of seven other Asteraceae had 62%-92% lower C. bombi infections than those fed non-Asteraceae pollen. Spine length, however, did not explain variation in bumble bee infection.4. Our study indicates that sunflower pollen's capacity to suppress C. bombi is driven by its spiny exine, and that this phenomenon extends to several other Asteraceae species. Our results indicate that sunflower pollen exines are as effective as whole pollen in reducing infection, suggesting that future studies should expand to assess the effects of other species with spiny pollen on pollinator-pathogen dynamics.