Analysis and modification of central carbon metabolism in Hypsizygus marmoreus for improving mycelial growth performance and fruiting body yield

Abstract

Hypsizygus marmoreus is one of the main industrially cultivated varieties of edible fungi, with a delicious taste and high nutritional value. However, the long harvest period of 130–150 days greatly limits its large-scale expansion. This study aimed to investigate the effects of central carbon metabolism (CCM) on the mycelial growth performance and fruiting body formation of H. marmoreus. Nine edible fungi with different harvest periods were collected and used to evaluate their intracellular carbon metabolic differences in the CCM, which revealed that the imbalanced distribution of intracellular carbon metabolic levels in the CCM of H. marmoreus might be one of the key factors resulting in a slow mycelial growth rate and a long harvest period. Further analysis by three strategies, including metabolomics, adaptation of different carbon sources, and chemical interference, confirmed that low carbon flux into the pentose phosphate pathway (PPP) limited the supply of raw materials, reduced power, and thus influenced the mycelial growth of H. marmoreus. Furthermore, four transformants with increased expression levels of glucose-6-phosphate dehydrogenase (G6PDH), a key rate-limiting enzyme in the PPP of H. marmoreus, were developed and showed more extracellular soluble protein secretion and higher sugar assimilation rates, as well as improved mycelial growth rates in bottle substrate mixtures. Finally, cultivation experiments indicated that the maturation periods of the fruiting body with ~4–5 days in advance and the maximum fruiting body yield of 574.8 g per bag with an increase of 7.4% were achieved by improving the G6PDH expression level of the PPP in H. marmoreus. This study showed that CCM played an important role in the mycelial growth and development of H. marmoreus, which provided new insights for future advancements in cultivating and breeding edible fungi.

The Promoting Mechanism of the Sterile Fermentation Filtrate of Serratia odorifera on Hypsizygus marmoreus by Means of Metabolomics Analysis

“…Meanwhile, the downregulation of glutamate and upregulation of ornithine in the upstream (Figures S6 and S7) also seemed to promote the flow of the TCA cycle. Lin et al also found the same result: low PPP metabolism level and unbalanced distribution of CCM in H. marmoreus were the two main factors contributing to the slow assimilation of carbon source and low mycelial growth rate [37]. It has been reported that QS signaling molecules have important effects on the physiological metabolism of microorganisms.…”

The effects of zinc sulfate on mycelial enzyme activity and metabolites of Pholiota adiposa

“…Furthermore, it determines the yield and quality of edible fungi. The mycelium of edible fungi degrades cellulose into monosaccharides through enzyme catalysis, providing nutrition for self-extension [ 14 ]. By examining the extracellular enzyme activity of edible fungi under different conditions, we can understand the decomposition degree and activity, and create an optimal environment for the growth of hyphae and sporangia [ 15 ].…”