Influences of Seasons, Latitudes, and Host Plants on Metabolic Changes in Cuscuta campestris Yunck

Abstract

To determine whether the metabolomic patterns of Cuscuta campestris vary with_x000D_ <br>season and latitude, samples were collected from parasitized individuals on the same_x000D_ <br>host plant. In order to include any potential metabolomic difference resulting from_x000D_ <br>host plant, the host plants were restricted to two species: Humulus japonicus and_x000D_ <br>Artemisia sp. Metabolite profiles of C. campestris were analyzed by different seasons_x000D_ <br>and latitudes conditions using gas chromatography-mass spectrometry (GC-MS)._x000D_ <br>Principal component analysis (PCA) was conducted to examine the metabolite_x000D_ <br>patterns and the PCA score plots of entire samples showed genetic influences more_x000D_ <br>than environmental influences: seasons and latitudes. When looking at the metabolite_x000D_ <br>patterns of C. campestris across the entire sample set, low latitude samples appear to_x000D_ <br>be relatively distinct from high and middle latitude samples. For samples with H._x000D_ <br>japonicus as the host plant, the metabolite pattern showed a clear distinction between_x000D_ <br>the middle latitude group and the other groups. these patterns did not show the_x000D_ <br>expected high-middle-low order. On the other hand, samples with Artemisia sp. as the_x000D_ <br>host plant, they tended to be well distinction among season and latitude groups_x000D_ <br>mainly when October samples were included._x000D_ <br>Multivariate analysis of variance (MANOVA) was used to interpret whether_x000D_ <br>statistically significant differences between the groups. The whole plant-seed group_x000D_ <br>was significant in all comparison. In the season groups using PCA scores, high_x000D_ <br>significances were observed only when compared to October, while comparisons_x000D_ <br>between other seasons were less significant or not significant. In the latitude groups,_x000D_ <br>the significant differences between groups were varied with each comparison._x000D_ <br>This study provides clues to understand the changes in metabolites of C._x000D_ <br>campestris from an ecological perspective. The limitations of this study included the_x000D_ <br>absence of Artemisia sp. related samples collected in the October season, the inability_x000D_ <br>to analyze the difference between the host plant with and without parasitism, and the_x000D_ <br>absence of environmental data.