Assessment of soil yeasts Papiliotrema laurentii S-08 and Saitozyma podzolica S-77 for plant growth promotion and biocontrol of Fusarium wilt of brinjal.

AIM: This study aimed to determine the efficacy of the soil yeasts Papiliotrema laurentii S-08 and Saitozyma podzolica S-77 for plant growth promotion (PGP) and biocontrol of wilt disease in brinjal plants while applying yeasts individually or as a consortium in pot experiments. METHODS AND RESULTS: The yeasts were tested for various PGP characteristics and antagonistic activity against the phytopathogen Fusarium oxysporum f. sp. melongenae. Both the yeast isolates demonstrated some PGP attributes as well as inhibited the growth of the phytopathogen. A gas chromatography-mass spectrometry analysis of the yeast metabolites revealed the presence of several antifungal compounds. The pot experiment performed under nursery conditions showed that applying these yeasts, individually or in consortium, decreased the percent disease incidence in brinjal seedlings while significantly enhancing their growth parameters. CONCLUSION: Papiliotrema laurentii S-08 and S. podzolica S-77 can be used in brinjal plants as plant growth promoters and also as biocontrol agents against the brinjal wilt disease.

Diversity and Heavy Metal Tolerance of Fungi Associated with Different Coal Overburden Strata of Tikak Colliery, Assam.

Coal mine overburdens are generally highly acidic and contaminated with toxic heavy metals. Here, we studied the culturable fungal diversity associated with different coal overburden strata (OBS) of Assam, India, and assessed their heavy metal tolerance ability against five different heavy metals viz., As3+, Cd2+, Cr6+, Cu2+, and Ni2+. Among 15 distinct coal OBS considered in this study which spans a depth of ~ 35 m from the ground surface, the isolation of fungi was successful only from 11 OBS samples and the colony-forming unit (CFU) counts were highly variable among the samples. A total of 66 fungal pure cultures were isolated which belong to 18 genera (17 known and 1 unknown) under 15 families and two divisions i.e., Ascomycota (89.4%) and Basidiomycota (10.6%). Acidiella bohemica was found relatively the most abundant species followed by Rhodotorula toruloides. A good number of fungal isolates was found tolerant to the test heavy metals at concentrations ≥ 1 mM. Findings of some multi-metallotolerant fungal isolates along with a tolerance up to 5 mM concentration of As3+, and up to 10 mM each of Cu2+, Cr6+, Ni2+ and Cd2+ were noteworthy in the present study that could be useful in the management of heavy metal pollution or stress. Cultivable fungal diversity of coal mine overburden strata of Tikak colliery, Margherita, Assam, India. It shows a photograph of the coal mining site as the background, front view of the fungal colonies in the upper section, and a graphical representation of heavy metal tolerance of the isolates at different concentrations of As, Cd, Cr, Cu, and Ni in the lower section.

Beer production potentiality of some non-Saccharomyces yeast obtained from a traditional beer starter emao.

The recent realisation regarding the potentiality of the long-neglected non-Saccharomyces yeasts in improving the flavour profile and functionality of alcoholic beverages has pushed researchers to search for such potent strains in many sources. We studied the fungal diversity and the rice beer production capability of the fungal strains isolated from emao-a traditional rice beer starter culture of the Boro community. Fifty distinct colonies were picked from mixed-culture plates, of which ten representative morphotypes were selected for species identification, and simultaneous saccharification and beer fermentation (SSBF) assay. The representative isolates were identified as Hyphopichia burtonii (Hbur-FI38, Hbur-FI44, Hbur-FI47 & Hbur-FI68), Saccharomyces cerevisiae (Scer-FI51), Wickerhamomyces anomalus (Wano-FI52), Candida carpophila (Ccar-FI53), Mucor circinelloides (Mcir-FI60), and Saccharomycopsis malanga (Smal-FI77 and Smal-FI84). The non-Saccharomyces yeast strains Hbur-FI38, Hbur-FI44, Ccar-FI53, and Smal-FI77 showed SSBF capacity on rice substrate producing beer that contained 7-10% (v/v) ethanol. A scaled-up fermentation assay was performed to assess the strain-wise fermentation behaviour in large-scale production. The nutritional, functional, and sensory qualities of the SSBF strain fermented beer were compared to the beer produced by emao. All the strains produced beer with reduced alcohol and energy value while compared to the traditional starter emao. Beer produced by both the strains of H. burtonii stood out with higher ascorbic acid, phenol, and antioxidant property, and improved sensory profile in addition to reduced alcohol and energy value. Such SSBF strains are advantageous over the non-SSBF S. cerevisiae strains as the former can be used for direct beer production from rice substrates.

Heavy metal tolerance of bacterial isolates associated with overburden strata of an opencast coal mine of Assam (India).

Coal overburden strata (OBS) vary in thickness, geochemical composition, and physical properties from stratum to stratum. Here, we enumerated the cultivable bacterial diversity and their distribution in different OBS taken from the opencast mining of Tikok colliery, Assam. The pH of the coal OBS ranged from 2.46 to 7.93, but 73% of the OBS was acidic. The OBS samples were mostly of shale types except for a few that were sandstone, mudstone, and red soil. The bacterial CFUs per gram OBS samples were highly diverse ranging from 52 to 57.4×104. A total of 79 bacterial pure culture isolates belonging to 19 genera, 12 family, and 3 phyla (Actinobacteria, Firmicutes, and Proteobacteria) were recovered in nutrient agar plates. Firmicutes appeared dominant over the others. All the isolates were screened for heavy metal tolerance in broth culture augmented with five different metals (Ni2+, Cu2+, Cr6+, As3+, and Cd2+) separately. The number of isolates that showed tolerance was 95% for Cr6+, 69.6% for Ni2+, 50.6% each for As3+ and Cu2+, and 7.6% for Cd2+. The bacterial isolates with high metal tolerance, i.e., 5 to 12 mM could be promising for bioremediation of Ni2+, Cu2+, Cr6+, and As3+ from the sites contaminated with these heavy metals.

Community structure and metabolic potentials of the traditional rice beer starter 'emao'.

The emao, a traditional beer starter used in the North-East regions of India produces a high quality of beer from rice substrates; however, its microbial community structure and functional metabolic modules remain unknown. To address this gap, we have used shot-gun whole-metagenome sequencing technology; accordingly, we have detected several enzymes that are known to catalyze saccharification, lignocellulose degradation, and biofuel production indicating the presence of metabolic functionome in the emao. The abundance of eukaryotic microorganisms, specifically the members of Mucoromycota and Ascomycota, dominated over the prokaryotes in the emao compared to previous metagenomic studies on such traditional starters where the relative abundance of prokaryotes occurred higher than the eukaryotes. The family Rhizopodaceae (64.5%) and its genus Rhizopus (64%) were the most dominant ones, followed by Phaffomycetaceae (11.14%) and its genus Wickerhamomyces (10.03%). The family Leuconostocaceae (6.09%) represented by two genera (Leuconostoc and Weissella) was dominant over the other bacteria, and it was the third-highest in overall relative abundance in the emao. The comprehensive microbial species diversity, community structure, and metabolic modules found in the emao are of practical value in the formulation of mixed-microbial cultures for biofuel production from plant-based feedstocks.

Molecular differentiation of Chenopodium album complex and some related species using ISSR profiles and ITS sequences.

The present study was undertaken to understand the genetic differentiation and relationships in various components of C. album complex, C. giganteum and some related species using inter simple sequence repeats (ISSR) profiles and internal transcribed spacer (ITS) sequences. The relationships based on UPGMA dendrograms have shown the heterogenous nature of C. album complex. The 2x taxa while showing close relation among themselves are sharply segregated from 4x and 6x taxa belonging to C. album and C. giganteum. Among the three cytotypes from North Indian plains the 4x shows greater similarity to 6x than to 2x which is corroborated by the karyotypic studies. Furthermore, the 6x C. album and C. giganteum accessions of American and European origin are clearly segregated from those of Indian origin which may show their separate origin. Other related species show relationships according to their taxonomic position. The present study based on ISSR profiles and ITS sequences has therefore been very useful in explaining the relationships between various components of C. album complex and related species. However, more work needs to be done using different CpDNA loci to define correct species boundary of the taxa under C. album complex from Himalayas and North Indian Plains.