Deciphering the salt induced morphogenesis and functional potentials of Hortaea werneckii; a black pigmented halotolerant yeast isolated from solar saltern

Abstract

An intense black pigmented halotolerant yeast GUBPC1, was obtained from the solar salterns of Nerul, Goa-India. The isolate could tolerate 0 to 20 % NaCl. FE-SEM analysis revealed its polymorphic nature, exhibiting oval cells at higher salt concentrations and filamentous spindle like shapes at lower concentrations. Initially, the cells appear oval, yeast like in shape but gradually after 15 days of incubation, it becomes elongated and undergoes budding, exhibiting various budding patterns, from single polar bud to bipolar buds with annellidic ring, to lateral buds and eventually forming filamentous hyphae. The intracellular black pigment was identified as melanin based on ultraviolet-visible spectroscopy analysis. The molecular identification of the culture showed closest similarity with Hortaea werneckii. Plant polymer-degrading enzymatic activities such as cellulase, laccase, chitinase, xylanase, pectinase, amylase and protease were exhibited by the isolate GUBPC1. To further understand and explore its biotechnological potential, we performed whole-genome sequencing and analysis. The obtained genome size was 26.93 Mb with 686 contigs and a GC content of 53.24 %. We identified 9383 protein-coding genes, and their functional annotation revealed the presence of 435 CAZyme genes and 16 functional genes involved in secondary metabolite synthesis, thus providing a basis for its potential value in various biotechnological applications.

Keywords: Black yeast; Halotolerant; Hortaea; Hydrolytic enzymes; Morphogenesis; Solar saltpans; Whole genome sequencing.