Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
J Proteome Res. 2010 Jan;9(1):298-307. doi: 10.1021/pr900622j.
Spore germination is the first step for fungal pathogens to infect host plants. The pH value, as one of the most important environmental parameters, has critical influence on spore germination. In this study, effects of ambient pH on spore germination were determined by culturing spores of Penicillium expansum in medium with pH values at 2.0, 5.0 and 8.0, and involved mechanisms were further investigated through methods of comparative proteomics. The results demonstrated that spore germination of P. expansum was obviously inhibited at pH 2.0 and 8.0. Using quadrupole time-of-flight tandem mass spectrometer, 34 proteins with significant changes in abundance were identified. Among them, 17 proteins were related to protein synthesis and folding, and most of them were down-regulated at pH 2.0 and 8.0. Accordingly, lower content of total soluble proteins and higher ratio of aggregated proteins were observed in spores at pH 2.0 and 8.0. In addition, it was found that ambient pH could affect intracellular pH and ATP level of P. expansum spores. These findings indicated that ambient pH might affect spore germination of P. expansum by changing intracellular pH and regulating protein expression. Further, impairing synthesis and folding of proteins might be one of the main reasons.
孢子萌发是真菌病原体感染宿主植物的第一步。pH 值是最重要的环境参数之一，对孢子萌发有至关重要的影响。在这项研究中，通过在 pH 值为 2.0、5.0 和 8.0 的培养基中培养扩展青霉的孢子，确定了环境 pH 值对孢子萌发的影响，并通过比较蛋白质组学的方法进一步研究了相关机制。结果表明，扩展青霉的孢子萌发在 pH 值为 2.0 和 8.0 时明显受到抑制。使用四极杆飞行时间串联质谱仪，鉴定出 34 种丰度有显著变化的蛋白质。其中，17 种与蛋白质合成和折叠有关，大多数在 pH 值为 2.0 和 8.0 时下调。因此，在 pH 值为 2.0 和 8.0 时，孢子中的总可溶性蛋白含量较低，聚集蛋白的比例较高。此外，还发现环境 pH 值可以影响扩展青霉孢子的细胞内 pH 值和 ATP 水平。这些发现表明，环境 pH 值可能通过改变细胞内 pH 值和调节蛋白质表达来影响扩展青霉孢子的萌发。进一步研究表明，蛋白质的合成和折叠受损可能是主要原因之一。
