Office of Research Administration, Chiang Mai University, Chiang Mai, Thailand.
Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Front Cell Infect Microbiol. 2024 Mar 13;14:1367656. doi: 10.3389/fcimb.2024.1367656. eCollection 2024.
Amoebae are micropredators that play an important role in controlling fungal populations in ecosystems. However, the interaction between fungi and their amoebic predators suggests that the pressure from predatory selection can significantly influence the development of fungal virulence and evolutionary processes. Thus, the purpose of this study was to investigate the adaptation of saprotrophic strains during their interactions with . We conducted a comprehensive analysis of survival after co-culture by colony counting of the yeast cells and examining yeast cell phenotypic and genetic characteristics. Our results indicated that exposure to amoebae enhanced the survival capacity of environmental and induced visible morphological alterations in , particularly by an increase in filamentation. These observed phenotypic changes were closely related to concurrent genetic variations. Notably, mutations in genes encoding transcriptional repressors ( and ), recognized for their negative regulation of filamentous growth, were exclusively identified in amoeba-passaged isolates, and absent in unexposed isolates. Furthermore, these adaptations increased the exposed isolates' fitness against various stressors, simultaneously enhancing virulence factors and demonstrating an increased ability to invade A549 lung human epithelial cells. These observations indicate that the sustained survival of under ongoing amoebic predation involved a key role of mutation events in microevolution to modulate the ability of these isolates to change phenotype and increase their virulence factors, demonstrating an enhanced potential to survive in diverse environmental niches.
变形虫是微小的捕食者，在控制生态系统中真菌种群方面发挥着重要作用。然而，真菌与其变形虫捕食者之间的相互作用表明，捕食选择的压力可以显著影响真菌毒力的发展和进化过程。因此，本研究旨在调查在与 相互作用过程中，腐生菌株的适应性。我们通过对酵母细胞进行共培养后的菌落计数和观察酵母细胞表型和遗传特征，对共生后的存活情况进行了全面分析。我们的结果表明，暴露于变形虫会增强环境 菌株的生存能力，并诱导 菌株发生明显的形态改变，特别是丝状生长增加。这些观察到的表型变化与同时发生的遗传变异密切相关。值得注意的是，仅在经过变形虫传代的分离株中发现了编码转录抑制剂（和）的基因突变，而在未暴露的分离株中则没有这些突变。此外，这些适应性增加了暴露分离株对各种胁迫的适应能力，同时增强了毒力因子，并表现出更强的侵袭 A549 肺人上皮细胞的能力。这些观察结果表明，在持续的变形虫捕食下， 菌株的持续生存涉及到微进化中的突变事件的关键作用，以调节这些分离株改变表型和增加毒力因子的能力，从而展示了在不同环境小生境中生存的增强潜力。
