The understanding of the selection factors that drive chemical diversification of secondary metabolites of constitutive defence systems in plants, such as pyrrolizidine alkaloids (PAs), is still incomplete. Historically, plants always have been confronted with microorganisms. Long before herbivores existed on this planet, plants had to cope with microbial pathogens. Therefore, plant pathogenic microorganisms may have played an important role in the early evolution of the secondary metabolite diversity. In this review, we discuss the impact that plant-produced PAs have on plant-associated microorganisms. The objective of the review is to present the current knowledge on PAs with respect to anti-microbial activities, adaptation and detoxification by microorganisms, pathogenic fungi, root protection and PA induction. Many in vitro experiments showed effects of PAs on microorganisms. These results point to the potential of microorganisms to be important for the evolution of PAs. However, only a few in vivo studies have been published and support the results of the in vitro studies. In conclusion, the topics pointed out in this review need further exploration by carrying out ecological experiments and field studies.

中文翻译：

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吡咯里西啶生物碱对微生物的防御特性。


对驱动植物组成防御系统次生代谢物（例如吡咯里西啶生物碱（PA））化学多样化的选择因素的理解仍然不完整。历史上，植物一直面临着微生物的威胁。早在这个星球上出现食草动物之前，植物就必须应对微生物病原体。因此，植物病原微生物可能在次生代谢多样性的早期进化中发挥了重要作用。在这篇综述中，我们讨论了植物产生的 PA 对植物相关微生物的影响。本次综述的目的是介绍 PA 在抗菌活性、微生物适应和解毒、病原真菌、根部保护和 PA 诱导等方面的最新知识。许多体外实验表明PAs对微生物的影响。这些结果表明微生物对于 PA 的进化具有重要的潜力。然而，只有少数体内研究已发表并支持体外研究的结果。总之，本文提出的主题需要通过开展生态实验和实地研究来进一步探索。