Evaluation of the effectiveness of RNA silencing in the filamentous fungus Aspergillus niger using a binary vector integrated with Gateway recombination cloning technology

Abstract

The filamentous fungus Aspergillus niger is widely employed in the production of citric acid and some industrial enzymes such as phytase, glucoamylase, and glucose oxidase. Currently, several genetic modification tools have been developed and applied to this fungal species. However, the RNA silencing technique is less used for A. niger. In the present study, an RNA silencing binary vector integrated with the Gateway recombination cloning technology was evaluated in A. niger. The integration of Gateway recombination cloning technology in binary vectors for rapid generation of hairpin RNA structure allowed the assessment of inhibition of target gene expression through mRNA degradation. The RNA silencing constructs were successfully transferred into A. nigervia Agrobacterium tumefaciens. Results showed that the RNA silencing vectors were effective in downregulating the expression of the DsRed fluorescent reporter gene and the stuA regulatory gene. Interestingly, the silenced mutants of stuA exhibited a significant reduction in fungal sporulation. This finding revealed that the RNA silencing technique with the examined Gateway binary vector represents a potential genetic tool for functional studies of target genes in A. niger.