Fungal disease suppression and growth promotion potential of endophytic bacteria from ethnomedicinal plants.

103 bacterial isolates obtained from 8 ethnomedicinal plants in Manipur, India were studied for antifungal and plant growth promoting (PGP) activities. Forty-six (46), out of 62 antifungal isolates, showed potent activities against R. solani. Since R. solani (RS), a sheath blight pathogen, threatens rice yields worldwide, the present study was aimed at discovering promising bioinoculants with anti-RS and PGP potential on rice. Twenty-nine (29) endophytic isolates exhibiting promising anti-RS and PGP activities were subjected to seed vigor assays on rice (var. Jatra) and 16 were found to enhance rice seedling vigour by 70% or more over the control. Four (4) strains, Streptomyces sp. (AcRz21), Alkalihalobacillus sp. (PtL11), Bacillus sp. (TgIb5), and Priestia sp. (TgIb12) with the highest vigor indices were studied for growth promotion of rice in field conditions under pathogen-challenged and pathogen-free conditions. These bioactive strains were able to significantly enhance root and shoot biomass and reduce lesion heights caused by R. solani.

Feather degradation by keratinolytic bacteria and biofertilizing potential for sustainable agricultural production.

Feathers account for 5-7% of the total weight of chicken have become one of the major pollutants due to their recalcitrant nature. Feather which is constituted of 90% keratin can be a good source of peptides, amino acids, and minerals for use as organic fertilizer. Traditional feather degradation methods consume large amount of energy and reduces the overall quality of the proteins. However, degradation of keratin by keratinolytic bacteria may represent as an alternative for the development of cheap, cost effective, eco-friendly, and easily available nitrogen (N) and minerals rich source as potential organic fertilizers. Keratinase enzymes from bacteria are serine-type proteases showing optimal activity at pH 6 to 9 and 30 to 50 °C. Mechanism of degradation includes, sulfitolysis, proteolysis, followed by deamination. Keratinolytic bacteria showing antagonism against important plant pathogens may act as biocontrol agent. Feather hydrolyzate can also be employed as nitrogenous fertilizers for plant growth. Tryptophan release from the feather degradation can act as precursor for plant phytohormone, indole-3-acetic acid (IAA). Solubilization of inorganic phosphate (P) by keratinolytic bacteria may further elevate the growth of plant. Application of hydrolyzate increases the water holding capacity, N, carbon (C) and mineral content of the soil. It elevates protein, amino acids, and chlorophyll content of plant. Feather hydrolyzate enhances seed germination and growth of plant. Soil application further increases the population of beneficial bacteria. The use of keratinolytic bacteria having antagonistic and plant growth promoting activities, and feather hydrolyzate can emerge as sustainable and alternative tools to promote and improve organic farming, agro-ecosystem, environment, human health, and soil biological activities.