Diversity and Distribution of Phenol Oxidase Producing Fungi from Soda Lake and Description of Curvularia lonarensis sp. nov.

Abstract

Soda lake is hyper alkaline and saline habitat located in closed craters with high evaporation rate. In current study fungal diversity from water and sediment samples of a soda lake (Lonar lake) located in Buldhana district of Maharashtra, India was investigated using extensive culturomics approach and mimicking the natural conditions of Lonar lake in culture media. A total of 104 diverse isolates of extremophilic fungi were recovered from this study and phylogenetically characterized by internal transcribed spacer (ITS) region sequencing. In addition, due to important role of phenol oxidase, and peroxidase in degradation of toxic phenol, lignin, etc., all isolated pure cultures were also screened for extracellular phenol oxidase and peroxidase production potential. Diversity analysis indicated that different groups of extremophilic fungi are present in the water and sediment samples of Lonar lake. A total of 38 species of fungi belonging to 18-different genera were recovered. Out of 104 isolates 32 showed ≤97% sequences similarity, which were morphologically different and could be potential novel isolates of extremophilic fungi. However, out of 104 isolates only 14 showed the extracellular phenol oxidase production potentials at alkaline pH. Curvularia sp. strain MEF018 showed highest phenol oxidase production at alkaline condition and had low sequence similarity with previously characterized species (96% with Curvularia pseudorobusta). Taxonomic characterization (morphological and physiological) and multi locus sequence analysis (MLSA) using combined alignment of ITS-LSU-gpd of strain MEF018 showed that it is a novel species of the genus Curvularia and hence proposed as Curvularia lonarensis sp. nov.

Cryptic species of Curvularia in the culture collection of the Queensland Plant Pathology Herbarium

“…Curvularia species have also been reported from substrates such as air (Almaguer et al 2012, Hargreaves et al 2013), aquatic environments (Verma et al 2013, Su et al 2015, Sharma et al 2016) and soil (Manamgoda et al 2011, Marin-Felix et al 2017a). …”

Oligotrophy vs. copiotrophy in an alkaline and saline habitat of Lonar Lake

“…It is the only crater formed due to the high-velocity meteoritic impact on basaltic rock. Many studies have reported the biodiversity associated with Lonar Soda Lake (Joshi et al, 2007 ; Pathak and Deshmukh, 2012 ; Tambekar and Dhundale, 2012 ; Sharma et al, 2016 ). Microbes isolated from the soda lake region manifest complex microbial food webs interconnecting various biological cycles via redox coupling.…”

Soil extracellular oxidases mediated nitrogen fertilization effects on soil organic carbon sequestration in bioenergy croplands

“…N fertilization has the potential to promote soil organic carbon (SOC) sequestration (Jian et al, 2016), although some studies show a negative or no effect of N fertilization on SOC sequestration (Aref & Wander, 1997; Brown et al, 2014; Khan et al, 2007). The contrasting effects of N fertilization on SOC stock partly lie in the differential responses of mineralization of slow turnover SOC fractions (e.g., lignin or litterfall; Dou et al, 2016), which are depolymerized by extracellular oxidative enzymes (oxidases) excreted by soil bacteria and fungi (Gallo et al, 2004; Sharma et al, 2016). As either plant inputs or indigenous SOC are chemically recalcitrant (Trumbore, 2000) and must be processed via microbial decomposition and oxidative catalyzation, the net changes of plant inputs and decomposition loss, that is, SOC accumulation, are likely represented by the dynamics of oxidases.…”