Plant pathogens challenge our efforts to maximize crop production due to their ability to rapidly develop resistance to pesticides. Fungal biocontrol agents have become an important alternative to chemical fungicides, due to environmental concerns related to the latter. Here we review the complex modes of action of biocontrol agents in general and epiphytic yeasts belonging to the genus Pseudozyma specifically and P. aphidis in particular. Biocontrol agents act through multiple direct and indirect mechanisms, which are mainly based on their secretions. We discuss the direct modes of action, such as antibiosis, reactive oxygen species-producing, and cell wall-degrading enzyme secretions which can also play a role in mycoparasitism. In addition, we discuss indirect modes of action, such as hyperbiotrophy, induced resistance and growth promotion based on the secretion of effectors and elicitors from the biocontrol agent. Due to their unique characteristics, epiphytic yeasts hold great potential for use as biocontrol agents, which may be more environmentally friendly than conventional pesticides and provide a way to reduce our dependency on fungicides based on increasingly expensive fossil fuels. No less important, the complex mode of action of Pseudozyma-based biocontrol agents can also reduce the frequency of resistance developed by pathogens to these agents.

中文翻译：

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基于分泌的生防剂作用模式，重点是蚜虫假单胞菌

由于植物病原体能够迅速发展出对农药的抗性，因此它们挑战了我们努力使农作物最大化的努力。由于与化学杀菌剂有关的环境问题，真菌生物防治剂已成为化学杀菌剂的重要替代品。在这里，我们审查了一般和附生酵母，具体地属于假单胞菌属和蚜虫的生防菌的复杂作用方式。特别是。生物防治剂通过多种直接和间接机制起作用，这些机制主要基于其分泌物。我们讨论了直接的作用方式，例如抗生，产生活性氧和降解细胞壁的酶分泌，这些也可在霉菌寄生中发挥作用。此外，我们讨论了间接作用方式，例如肥大细胞肥大，诱导的抗性和基于生物防治剂分泌的效应子和激发子的生长促进。由于附生酵母具有独特的特性，因此它们有很大的潜力用作生物防治剂，它可能比传统农药对环境更友好，并为减少我们对日益昂贵的化石燃料对杀菌剂的依赖性提供了一种途径。同样重要的是，复杂的行动方式基于假酶的生物防治剂还可以降低病原体对这些药剂产生的抗药性的频率。