Metabolomics Australia, Murdoch University, Perth 6150, WA, Australia.
Separation Science and Metabolomics Laboratory, Murdoch University, Perth 6150, WA, Australia.
Microbiology (Reading). 2013 Sep;159(Pt 9):1972-1985. doi: 10.1099/mic.0.067009-0. Epub 2013 Jun 6.
Mutants of the wheat pathogenic fungus Stagonospora nodorum lacking G-protein subunits display a variety of phenotypes including melanization defects, primary metabolic changes and a decreased ability to sporulate. To better understand the causes of these phenotypes, Stagonospora nodorum strains lacking a Gα, Gβ or Gγ subunit were compared to a wild-type strain using metabolomics. Agar plate growth at 22 °C revealed a number of fundamental metabolic changes and highlighted the influential role of these proteins in glucose utilization. A further characterization of the mutants was undertaken during prolonged storage at 4 °C, conditions known to induce sporulation in these sporulation-deficient signalling mutants. The abundance of several compounds positively correlated with the onset of sporulation including the dissacharide trehalose, the tryptophan degradation product tryptamine and the secondary metabolite alternariol; metabolites all previously associated with sporulation. Several other compounds decreased or were absent during sporulation. The levels of one such compound (Unknown_35.27_2194_319) decreased from being one of the more abundant compounds to absence during pycnidial maturation. This study has shed light on the role of G-protein subunits in primary metabolism during vegetative growth and exploited the cold-induced sporulation phenomenon in these mutants to identify some key metabolic changes that occur during asexual reproduction.
小麦病原菌旋孢腔菌突变体缺乏 G 蛋白亚基，表现出多种表型，包括黑化缺陷、初级代谢变化和产孢能力下降。为了更好地理解这些表型的原因，使用代谢组学比较了缺乏 Gα、Gβ 或 Gγ 亚基的旋孢腔菌菌株与野生型菌株。在 22°C 的琼脂平板生长中发现了许多基本的代谢变化，并强调了这些蛋白质在葡萄糖利用中的重要作用。在已知会诱导这些产孢缺陷信号突变体产孢的 4°C 下长时间储存时，对突变体进行了进一步的表征。与产孢相关的几种化合物的丰度与产孢的开始呈正相关，包括二糖海藻糖、色氨酸降解产物色胺和次级代谢物交链孢酚；所有这些代谢物以前都与产孢有关。其他几种化合物在产孢过程中减少或不存在。这样一种化合物（Unknown_35.27_2194_319）的水平从一种较丰富的化合物下降到在产孢体成熟过程中消失。本研究阐明了 G 蛋白亚基在营养生长过程中的初级代谢中的作用，并利用这些突变体中冷诱导产孢现象来鉴定在无性繁殖过程中发生的一些关键代谢变化。
