The spatiotemporal-specific regulation of cell wall-related proteins promotes the secretion of pigments in Antarctic fungi Geomyces sp. wnf-18c.

The polar environment harbors extremely rich and valuable natural product resources. In this study, a strain of Antarctic fungus, Geomyces sp. wnf-18c, in Antarctic soil was isolated in a laboratory. This fungus produces a purplish-red pigment whose hue closely resembles that of the high-end pigment carminic acid. However, approximately 50 % of the pigment remains within the fungal hyphae, restricting subsequent separation and extraction. In this study, the deletion of the key cell wall protein-encoding genes CHS3 and AGS1 enhanced pigment secretion. It also considerably inhibited the strain's growth, making it difficult to substantially increase the total pigment yield. To overcome these hurdles, the xylose-inducible system from Trichoderma reesei was heterologously expressed in Antarctic fungi, and the CRISPR-Cas9 system was placed under the control of this induction system. The exogenous addition of xylose as a signal to initiate genetic editing achieved the spatiotemporal regulation of the target gene-activating gene editing that restricts growth only after the completion of the strain's growth phase. The spatiotemporal regulation of key cell wall proteins significantly mitigated growth inhibition, greatly enhanced pigment secretion, and raised the total pigment yield. This discovery advances our understanding of the spatiotemporal specificity and dynamic regulation of microorganisms, offering novel strategies for exploiting polar microbial resources and reducing industrial production costs.