Cloning And Disruption Of Polarized Growth Genes And The Effects On Fermentation In Shear-sensitive Marine Fungus Aspergillus Glaucus

Marine-derived filamentous fungus Aspergillus glaucus HB1-19, producing a novel anti-tumor compound aspergiolide A, is significantly sensitive to mechanical shear stress, which makes it difficult for its fermentation scale-up in bioreactor. In this study, we aim to modify the hyphal morphology by disruption of polarized growth genes and identify whether the curved hyphae can resist to shear stress to some extent.Degenerate PCR and genome walking methods were used to obtain the gene sequences of polarized growth genes AgKipA, AgTeaA and AgTeaR, followed by construction of AgKipA and AgTeaR mutants by homologous integration of double crossover with the zeocin resistance gene Sh ble as a marker. The hyphae of the two mutants both became curved and the AgKipA mutant appeared more curved than the AgTeaR one. The germination of second germ tube from conidiospores of the two mutants was different from the wild type strain as well, while the growth rate and development of the two mutants showed no difference from the wild type strain. Glass beads were added to the submerged culture to indentify the shear-resistance of the mutants, and the curved hyphae showed no remarkably resistant to shear stress, whereas the color of the fermentation broth and the hyphal clusters of the mutants were changed. And the fermentation period of△AgKipA was shortened by 24 h compared with that of the A. glaucus wild type, which can greatly reduce the cost in industrial production.