PDF(Pubmed)
Abstract：
Aspergillus ochraceus is the traditional ochratoxin A (OTA)-producing fungus with density-dependent behaviors, which is known as quorum sensing (QS) that is mediated by signaling molecules. Individual cells trend to adapt environmental changes in a \"whole\" flora through communications, allowing fungus to occupy an important ecological niche. Signals perception, transmission, and feedback are all rely on a signal network that constituted by membrane receptors and intracellular effectors. However, the interference of density information in signal transduction, which regulates most life activities of Aspergillus, have yet to be elucidated. Here we show that the G protein-coupled receptor (GPCR) to cAMP pathway is responsible for transmitting density information, and regulates the key point in life cycle of A. ochraceus. Firstly, the quorum sensing phenomenon of A. ochraceus is confirmed, and identified the density threshold is 103 spores/mL, which represents the low density that produces the most OTA in a series quorum density. Moreover, the GprC that classified as sugar sensor, and intracellular adenylate cyclase (AcyA)-cAMP-PKA pathway that in response to ligands glucose and HODEs are verified. Furthermore, GprC and AcyA regulate the primary metabolism as well as secondary metabolism, and further affects the growth of A. ochraceus during the entire life cycle. These studies highlight a crucial G protein signaling pathway for cell communication that is mediated by carbohydrate and oxylipins, and clarified a comprehensive effect of fungal development, which include the direct gene regulation and indirect substrate or energy supply. Our work revealed more signal molecules that mediated density information and connected effects on important adaptive behaviors of Aspergillus ochraceus, hoping to achieve comprehensive prevention and control of mycotoxin pollution from interrupting cell communication.
摘要：
曲霉是一种传统的产生曲霉毒素A（OTA）的真菌，具有密度依赖的行为，这被称为群体感应（QS），由信号分子介导。单个细胞通过通讯来适应环境变化的趋势，让真菌占据重要的生态位。信号感知，传输,和反馈都依赖于由膜受体和细胞内效应子构成的信号网络。然而,密度信息在信号转导中的干扰，调节曲霉的大部分生命活动，尚未阐明。在这里，我们表明，G蛋白偶联受体（GPCR）cAMP途径负责传递密度信息，并调节了A.ochracus生命周期的关键点。首先,确认了A.ochracus的群体感应现象，并确定密度阈值为103孢子/mL，这表示在一系列法定密度中产生最多OTA的低密度。此外，被归类为糖传感器的GprC，以及响应于配体葡萄糖和HODE的细胞内腺苷酸环化酶（AcyA）-cAMP-PKA途径被证实。此外，GprC和AcyA调节初级代谢和次级代谢，并进一步影响A.ochracus在整个生命周期中的生长。这些研究强调了由碳水化合物和氧化脂素介导的细胞通讯的关键G蛋白信号通路，并阐明了真菌发育的综合作用，其中包括直接的基因调控和间接的底物或能量供应。我们的工作揭示了更多的信号分子，这些信号分子介导了密度信息，并对曲霉的重要适应行为产生了关联效应，希望通过阻断细胞通讯实现对霉菌毒素污染的综合防治。
