The genus Flindersia (Rutaceae) comprises 17 species of mostly Australian endemic trees. Although most species are restricted to rainforests, four have evolved to grow in semi-arid and arid environments. In this study, the leaf alkaloid diversity of rainforest and semi-arid/arid zone adapted Australian Flindersia were compared by LC/MS-MS and NMR spectroscopy. Contrary to expectations, Flindersia alkaloid diversity was strongly correlated with environmental aridity, where species predominating in drier regions produced more alkaloids than their wet rainforest congenerics. Rainforest species were also more chemically similar to each other than were the four semi-arid/arid zone species. There was a significant relationship between the presence of alkaloid structural classes and phylogenetic distance, suggesting that alkaloid profiles are influenced by both genetic and environmental factors. The results suggest that the radiation of Flindersia species out of the rainforest and into drier environments has promoted the evolution of unique alkaloid diversity. Plants growing in arid and semi-arid regions of Australia may represent an untapped source of undescribed specialised metabolites.

中文翻译：

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由适应干旱驱动的澳大利亚弗林德西亚（芸香科）物种叶片中的生物碱多样性

Flindersia 属（芸香科）包括 17 种主要是澳大利亚特有的树木。尽管大多数物种仅限于热带雨林，但有四种已经进化到在半干旱和干旱环境中生长。在这项研究中，通过 LC/MS-MS 和 NMR 光谱比较了适应澳大利亚弗林德西亚的雨林和半干旱/干旱区的叶子生物碱多样性。与预期相反，弗林德西亚生物碱多样性与环境干旱密切相关，在干燥地区占主导地位的物种比其潮湿的雨林同系植物产生更多的生物碱。与四种半干旱/干旱地区物种相比，雨林物种在化学上也更加相似。生物碱结构类别的存在与系统发育距离之间存在显着关系，表明生物碱谱受遗传和环境因素的影响。结果表明，Flindersia 物种离开雨林并进入干燥环境的辐射促进了独特生物碱多样性的进化。生长在澳大利亚干旱和半干旱地区的植物可能是未描述的特殊代谢物的未开发来源。