冠突曲霉Ac-nsdD基因鉴定分析及抗盐胁迫功能分析.

[Objective] The regulation of GATA transcription factor Ac-nsdD in Aspergillus cristatus of Fu brick tea was further researched.[Method] The The characteristic of Ac-NsdD protein sequence of A. cristatus was analyzed by genome sequencing and annotation and phylogenetic construction. The Ac-nsdD deletion mutant was constructed by homologous recombination via Agrobacterium tumefaciens-mediated transformation, and the phenotype of the A. cristatus mutant was analyzed. [Result] Based on the genome sequencing and annotation, A. cristatus Ac-nsdD encoded a putative transcription factor with a conserved DNA-binding domain, ZnF GATA. Phylogenetic analysis showed that A. cristatus Ac-nsdD gene was closely related to other homologs from filamentous fungal species. The Ac-nsdD gene deletion mutant strain during in vitro cultivation in M3 Y medium displayed the number of cleistothecium decreased significantly when compared with their wild type.Interestingly, during in vitro cultivation in M3 Y medium containing 5% NaCl, the mutant strain showed the amount of cleistothecium was decreased, the amount of conidiation was significantly increased, growth rate slower, pigment formation in the middle of the medium was significantly increased. Furthermore, during in vitro cultivation in M3 Y medium containing 17% NaCl, the Ac-nsdD gene mutant showed the amount of cleistothecium was reduced to nearly zero, the amount of conidiation was decreased, growth rate slower. [Conclusion]. The Ac-nsdD gene in a salt-free environment might have a positive effect on sexual development in A. cristatus. In response to low salt-induced osmotic stress, Ac-nsdD gene might positively regulate sexual reproduction, negatively regulate asexual development, maintain a developmental balance between asexual and sexual sporulation, be involved in pigment biosynthesis. The Ac-nsdD gene might negatively regulate sexual development, asexual development and vegetative growth in response to high salt-induced osmotic stress. This study provides laboratory generated data support for further study of the signaling pathways and downstream-regulated genes associated with Ac-nsdD gene, and for common and unique signal transduction pathways in sexual and asexual development in filamentous fungi. [ABSTRACT FROM AUTHOR]