Assour Hannah R, Ashman Tia-Lynn, Turcotte Martin M
Department of Biological Sciences, University of Pittsburgh, Dietrich School of Arts and Sciences, Pittsburgh, 15260, PA, USA.
Am J Bot. 2024 Aug;111(8):e16301. doi: 10.1002/ajb2.16301. Epub 2024 Mar 11.
Polyploidy is a widespread mutational process in angiosperms that may alter population performance of not only plants but also their interacting species. Yet, knowledge of whether polyploidy affects plant-herbivore dynamics is scarce. Here, we tested whether aphid herbivores exhibit preference for diploid or neopolyploid plants, whether polyploidy impacts plant and herbivore performance, and whether these interactions depend on the plant genetic background.
Using independently synthesized neotetraploid strains paired with their diploid progenitors of greater duckweed (Spirodela polyrhiza), we evaluated the effect of neopolyploidy on duckweed's interaction with the water-lily aphid (Rhopalosiphum nymphaeae). Using paired-choice experiments, we evaluated feeding preference of the herbivore. We then evaluated the consequences of polyploidy on aphid and plant performance by measuring population growth over multiple generations.
Aphids preferred neopolyploids when plants were provided at equal abundances but not at equal surface areas, suggesting the role of plant population surface area in driving this preference. Additionally, neopolyploidy increased aphid population performance, but this result was dependent on the plant's genetic lineage. Lastly, the impact of herbivory on neopolyploid vs. diploid duckweed varied greatly with genetic lineage, where neopolyploids appeared to be variably tolerant compared to diploids, sometimes mirroring the effect on herbivore performance.
By experimentally testing the impacts of polyploidy on trophic species interactions, we showed that polyploidization can impact the preference and performance of herbivores on their plant hosts. These results have significant implications for the establishment and persistence of plants and herbivores in the face of plant polyploidy.
多倍体是被子植物中一种广泛存在的突变过程，它不仅可能改变植物的种群表现，还会影响与其相互作用的物种。然而，关于多倍体是否影响植物与食草动物之间的动态关系，目前的了解还很少。在此，我们测试了蚜虫食草动物是否对二倍体或新多倍体植物表现出偏好，多倍体是否影响植物和食草动物的表现，以及这些相互作用是否取决于植物的遗传背景。
我们使用独立合成的新四倍体菌株及其二倍体祖先——紫萍（Spirodela polyrhiza），评估了新多倍体对紫萍与睡莲蚜（Rhopalosiphum nymphaeae）相互作用的影响。通过配对选择实验，我们评估了食草动物的取食偏好。然后，我们通过测量多代的种群增长，评估了多倍体对蚜虫和植物表现的影响。
当提供等量的植物时，蚜虫更喜欢新多倍体，但当植物表面积不等时则不然，这表明植物种群表面积在驱动这种偏好中发挥了作用。此外，新多倍体增加了蚜虫的种群表现，但这一结果取决于植物的遗传谱系。最后，食草动物对新多倍体和二倍体紫萍的影响因遗传谱系而异，与二倍体相比，新多倍体似乎具有不同程度的耐受性，有时反映出对食草动物表现的影响。
通过实验测试多倍体对营养物种相互作用的影响，我们发现多倍体化会影响食草动物对其植物宿主的偏好和表现。这些结果对于面对植物多倍体时植物和食草动物的建立与持续存在具有重要意义。
