Citrate synthase gene comparison and use of RAPD genomic fingerprinting to study relatedness among different Aspergillus sp (912.1)

Abstract

In the present study, we studied polymorphism in two strains of Aspergillus niger for the expression of citrate synthase (CS) gene. To elucidate the positions of mutations and to study sequence comparison, the CS gene from both wild and mutant strains was cloned and sequenced. On the basis of these partial sequences, a dendogram was made to assess homology among different strains of A. niger. Random amplified polymorphic DNA (RAPD‐PCR) analysis was also employed to study genetic variation between wild and mutant strains of A. niger and in total 31 decamer random primers were surveyed. A mutation was induced in the fungus using ethidium bromide resulted in enhanced expression of citric acid by three folds. RAPD‐PCR was executed which confirmed a significant change in the genetic makeup of mutant strain related with genotypic variability. Out of 31 decamer random primers, 15 showed polymorphism by amplifying polymorphic fragments units of total 98 and only 71.43% similarity was found between both the genomes. Keeping in view the importance of citric acid as a necessary constituent of various food preparations, synthetic biodegradable detergents and pharmaceuticals the enhanced production of citric acid by mutant derivative might provide significant boost in commercial scale viability of this useful product.Grant Funding Source: Supported by Higher Education Commission, Government of Pakistan