Function Analysis Of Gene AgLigD And Preliminary Identification Of Light Sensing In Marine-Derived Filamentous Fungus Aspergillus Glaucus

Filamentous fungi from the marine environment have shown great potential in the discovery of new compound, but extremely low frequency of homologous recombination brings difficulty to further molecular studies. Previous work has shown that nonhomologous end joining (NHEJ) is a predominant pathway for DNA double-strand breaks (DSB) repair of the most eukaryotic other than yeast. To develop a highly efficient gene targeting system applicable to marine-derived filamentous fungus Aspergillus glaucus(A. glaucus), we identified and deleted the A. glaucus AgLigD, which homolog of N. crassa Mus-53 is considered to play a significant role in NHEJ, and frequency of TGR exhibited dramatically increase (up to 85% vs. 0% in the wild type) as deduced from targeting AgPyrG gene, when containing 1000 bp of homologous flanking sequence. Such results strongly indicate that AgLigD is indeed involved in the repair of NHEJ in A. glaucus and function in this pathway. However, the AgLigD-defective mutant has no discernible differences with wild type regarding sensitivity to mutagens and UV, growth characteristics and transformation frequency. Light sensing is essential for organisms in all biological kingdoms to adapt to different environmental conditions and play a key role in many different physiological responses such as asexual conidiation, the circadian clock, secondary metabolism, pigmentation and sexual development, etc. To further study light sensing system, we isolated and characterized Agwc1, Agwc2, AgveA, AgFphA, encoding putative different light regulators, respectively, in marine-derived filamentous fungus Aspergillus glaucus. Several kinds of bioinformatics methods were used to analyze information of protein and nucleotide about these four light regulators. In addition, growth, development characteristics and product of secondary metabolism were further studied in different light conditions. Large numbers of conidiospores were only produced in light, suggesting an activation of sexual development. However, the number of cleistothecia was more in the dark than in light, indicating that asexual development occupies predominant status in the dark. Furthermore, product of secondary metabolism has a significantly increase in red light condition.