Genome-wide identification and comparative in-silico characterization of ß-galactosidase (GH-35) in ascomycetes and its role in germ tube development of Aspergillus fumigatus via RNA-seq analysis.

ß-galactosidase (Lactase), an enzyme belonging to the glycoside hydrolase family causing the hydrolysis and trans-glycosylation of ß-D-galactosides, has a vital role in dairy industries. The current investigation emphasizes on in-silico identification and comparative analysis of different fungal lactases present in Aspergillus fumigatus, Aspergillus oryzae, Botrytis cinerea, and Fusarium fujikuroi. Prediction of motifs and domains, chromosomal positioning, gene structure, gene ontology, sub-cellular localization and protein modeling were performed using different bioinformatics tools to have an insight into the structural and functional characteristics of ß-galactosidases. Evolutionary and homology relationships were established by phylogenetic and synteny analyses. A total of 14 ß-gal genes (GH-35) were identified in these species. Identified lactases, having 5 domains, were predicted to be stable, acidic, non-polar and extracellularly localized with roles in polysaccharide catabolic process. Results showed variable exonic/intronic ratios of the gene structures which were randomly positioned on chromosomes. Moreover, synteny blocks and close evolutionary relationships were observed between Aspergillus fumigatus and Aspergillus oryzae. Structural insights allowed the prediction of best protein models based on the higher ERRAT and Q-MEAN values. And RNA-sequencing analysis, performed on A. fumigatus, elucidated the role of ß-gal in germ tube development. This study would pave the way for efficient fungal lactase production as it identified ß-gal genes and predicted their various features and also it would provide a road-way to further the understanding of A. fumigatus pathogenicity via the expression insights of ß-gal in germ tube development.

An Overview of Mycoviral Curing Strategies Used in Evaluating Fungal Host Fitness.

The number of novel mycoviruses is increasing at a high pace due to advancements in sequencing technologies. As a result, an uncountable number of mycoviral sequences are available in public sequence repositories. However, only genomic information is not sufficient to understand the impact of mycoviruses on their host biology. Biological characterization is required to determine the nature of mycoviruses (cryptic, hypervirulent, or hypovirulent) and to search for mycoviruses with biocontrol and therapeutic potential. Currently, no particular selective method is used as the gold standard against these mycoviral infections. Given the importance of curing, we present an overview of procedures used in preparation of isogenic lines, along with their benefits and drawbacks. We concluded that a combination of single-spore isolation and hyphal tipping is the best fit for preparation of isogenic lines. Furthermore, recent bioinformatic approaches should be introduced in the field of mycovirology to predict virus-specific antivirals to get robust results.