Comprehensive, classical and molecular characterization methods of Saprolegnia (Oomycota; Stramnipila), an important fungal pathogen of fish

The fish fungal pathogen (Saprolegnia) belonging to heterokonts group, causing Saprolegniosis, received considerable attention among all the fungal pathogens of fish. The pathogen is widely distributed to aquatic habitat and is an economically important member of the class Oomycetes. The genus comprises of opportunistic biotrophic or parasitic pathogens of fish and relevant aquatic organisms. The atrocities of pathogen account for few million dollar losses to the aquaculture production worldwide. It has also remained linked to the cosmopolitan decline in wild fish stocks, amphibian, and crustacean populations. In order to overcome the burden of the disease, there is a crucial need to develop strategies for the effective management of Saprolegniosis. However, in order to manage the disease burden, there is a basic requirement to understand the phylogeny, taxonomy and molecular mechanism involved in the disease progression. With the tremendous advent and escalation in the fungal genome sequencing projects which helped in understanding the novelties of many fungal taxa so far, there is still dearth in the molecular information available on Saprolegnia spp. Owing to the scarcity of the cumulative information pool, there arises a need to assemble phylogenetic, taxonomic and molecular data of Saprolegniales along with their transcriptomic data from various databases available, so that the consolidated information be made accessible to the researchers. In the above context, this review shall serve as an important information resource on the overall biological aspects of Saprolegnia spp., and a way forward to tackle this pathogen efficiently. Various genomic and transcriptomic studies discussed shall enlighten the understanding of Saprolegnia pathogenesis mechanisms and subsequently benefit in framing strategies to contain the pathogen efficiently.