Rosli Muhammad Aqil Fitri, Mediani Ahmed, Azizan Kamalrul Azlan, Baharum Syarul Nataqain, Goh Hoe-Han
Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi, Malaysia.
Front Plant Sci. 2021 Apr 21;12:655004. doi: 10.3389/fpls.2021.655004. eCollection 2021.
Hybridization is key to the evolution and diversity of plants in nature. Nepenthaceae comprises a family of diverse tropical carnivorous pitcher plant species with extensive hybridization. However, there is no study to date on the metabolite expression of hybrids in this family. We performed a non-targeted metabolomics analysis of the pitchers of two species with different dietary habits, namely, the semi-detritivorous and carnivorous with their hybrid (. × ) for a comparative study. The whole-pitcher samples were extracted in methanol:chloroform:water (3:1:1) via sonication-assisted extraction and analyzed using ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) followed by data analysis to profile chemical compositions. A total of 1,441 metabolite features were profiled from the three species in which 43.3% of features in the hybrid samples were not found in either of its parents. The partial least squares discriminant analysis (PLS-DA) found 324 metabolite features with variable in projection (VIP) values greater than one in which 55 features were statistically significant. This showed that the hybrid is closer to . , which is consistent to the previous study on gene and protein expressions. A total of 105 metabolites were putatively identified with manual searches using public metabolite databases. Phenols were detected to be the most abundant secondary metabolites due to a high flavonoid content, especially in . The most abundant feature 476.3s:449.102 was found to be the most significant VIP for distinguishing between the three species as a chemical marker. This is the first study comparing metabolites in the carnivory organs of different species with comprehensive profiling and putative identification. The differential metabolite compositions in the pitchers of different species might have ecological implications with the hybrid showing intermediate phenotype between the parents as well as manifesting unique metabolites. However, there is no clear evidence of metabolites related to the differences in dietary habits between the hybrid and the two parent species.
杂交是自然界中植物进化和多样性的关键。猪笼草科包含一系列多样的热带食肉猪笼草物种，存在广泛的杂交现象。然而，迄今为止尚无关于该科杂交种代谢物表达的研究。我们对两种具有不同食性的猪笼草进行了非靶向代谢组学分析，这两种猪笼草分别为半腐食性和肉食性，同时分析了它们的杂交种（. × ），以进行比较研究。通过超声辅助提取，将整个猪笼草样本用甲醇：氯仿：水（3:1:1）进行提取，并使用超高效液相色谱飞行时间质谱（UPLC - TOF - MS）进行分析，随后进行数据分析以描绘化学成分。从这三个物种中共描绘出1441个代谢物特征，其中杂交样本中有43.3%的特征在其亲本中均未发现。偏最小二乘判别分析（PLS - DA）发现324个投影变量重要性（VIP）值大于1的代谢物特征，其中55个特征具有统计学意义。这表明杂交种更接近. ，这与之前关于基因和蛋白质表达的研究一致。通过使用公共代谢物数据库进行人工搜索，共初步鉴定出105种代谢物。由于黄酮类化合物含量高，酚类被检测为最丰富的次生代谢物，尤其是在. 中。发现最丰富的特征476.3s:449.102作为化学标志物，是区分这三个物种的最显著VIP。这是第一项对不同物种食肉器官中的代谢物进行全面描绘和初步鉴定比较的研究。不同物种猪笼草中代谢物组成的差异可能具有生态意义，杂交种表现出介于亲本之间的中间表型以及独特的代谢物。然而，没有明确证据表明杂交种与两个亲本物种在食性差异方面存在相关代谢物。
