Some strains of Aspergillus niger have been previously reported to produce sclerotia under certain conditions. Sclerotia are aggregations of hyphae which can act either as survival or as sexual structures in species related to A. niger. In this study, we were able to induce the formation of sclerotia in the progenitor of the industrial citric acid producing strains of A. niger, ATCC 1015, and in pyrG mutants derived from it. Sclerotia can be stably formed by ATCC 1015 on malt extract agar medium supplemented with raisins, showing a spatial differentiation of the fungus dependent on the addition and on the position of the fruits into the medium. On other media, including malt extract agar, pyrG auxotrophs also form abundant sclerotia, while the complementation of this gene reverses this phenotype. Additionally, a macro- and microscopical analysis of the sclerotia is reported. Our results show that the sclerotia formed by A. niger are similar to those formed by other fungi, not only in their morphology but also in their ability to germinate and regenerate the organism.

先前已报道黑曲霉的一些菌株在某些条件下产生菌核。菌核是菌丝的聚集体，可以作为与黑曲霉有关的物种的存活或有性结构。在这项研究中，我们能够在黑曲霉的工业柠檬酸生产菌株ATCC 1015的祖先中以及从它衍生的pyrG突变体中诱导菌核的形成。ATCC 1015 可以在添加了葡萄干的麦芽提取物琼脂培养基上稳定形成菌核，显示出真菌的空间分化取决于添加量和果实在培养基中的位置。在其他培养基上，包括麦芽提取物琼脂、pyrG营养缺陷型也形成丰富的菌核，而该基因的互补逆转了这种表型。此外，还报告了菌核的宏观和微观分析。我们的结果表明，A. niger形成的菌核与其他真菌形成的菌核相似，不仅在形态上而且在它们发芽和再生生物体的能力上。