State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, P. R. China.
J Microbiol. 2021 Apr;59(4):426-434. doi: 10.1007/s12275-021-0433-0. Epub 2021 Jan 26.
The prominent protein producing workhorse Trichoderma reesei secretes a typical yellow pigment that is synthesized by a gene cluster including two polyketide synthase encoding genes sor1 and sor2. Two transcription factors (YPR1 and YPR2) that are encoded in the same cluster have been shown to regulate the expression of the sor genes. However, the physiological relevance of the yellow pigment synthesis in T. reesei is not completely clear. In this study, a yellow pigment hyper-producer OEypr1 and three yellow pigment non-producers, OEypr1-sor1, Δypr1, and OEypr2, were constructed. Their phenotypic features in mycelial growth, conidiation, cell wall integrity, stress tolerance, and cellulase production were determined. Whereas hyperproduction of the yellow pigment caused significant defects in all the physiological aspects tested, the non-producers showed similar colony growth, but improved conidiation, maintenance of cell wall integrity, and stress tolerance compared to the control strain. Moreover, in contrast to the severely compromised extracellular cellobiohydrolase production in the yellow pigment hyperproducer, loss of the yellow pigment hardly affected induced cellulase gene expression. Our results demonstrate that interfering with the yellow pigment synthesis constitutes an engineering strategy to endow T. reesei with preferred features for industrial application.
里氏木霉（Trichoderma reesei）分泌一种典型的黄色色素，这种色素由一个包含两个聚酮合酶编码基因 sor1 和 sor2 的基因簇合成。该基因簇中编码的两个转录因子（YPR1 和 YPR2）已被证明可以调节 sor 基因的表达。然而，黄色色素合成在里氏木霉中的生理相关性尚不完全清楚。在这项研究中，构建了一个黄色色素高产菌 OEypr1 和三个黄色色素非产生菌 OEypr1-sor1、Δypr1 和 OEypr2。测定了它们在菌丝生长、产孢、细胞壁完整性、应激耐受和纤维素酶生产方面的表型特征。虽然黄色色素的过度产生导致了所有测试的生理方面的显著缺陷，但非产生菌的菌落生长与对照菌株相似，但产孢、细胞壁完整性的维持和应激耐受得到了改善。此外，与黄色色素高产菌中严重受损的细胞外纤维二糖水解酶的产生相比，黄色色素的缺失几乎没有影响诱导的纤维素酶基因表达。我们的结果表明，干扰黄色色素的合成是赋予里氏木霉工业应用所需特性的一种工程策略。
