Department of Biotechnology, Pillai College of Arts, Commerce and Science-Autonomous, 10, Sector-16, New Panvel, Navi Mumbai, Maharashtra, India
*Corresponding author: pillai_gopakumar@yahoo.co.in (ORCID ID: 0000-0003-0060-6523)
Online published on 3 September, 2022.
Indian mustard (Brassica juncea) is one of the important oilseeds produced in India. It is used as an ingredient in the preparation of various cuisines and used as a green manure by vegetable growers. Overuse of chemical fertilizers, poor irrigation facilities, and other anthropogenic activities has led to increased salt concentrations in the soil. Salt stress has been found to decline the growth and yield of Indian mustard. Salinity negatively affects seed germination, which is the first stage of the plant’s life cycle. Excessive salt has a huge impact on plant physiology. Mangrove soil provides shelter to various halotolerant plant growth-promoting bacteria like Azotobacter, which may provide a tool for sustainable crop improvement due to their multifarious features. Two fast-growing efficient isolates of halotolerant Azotobacter spp viz., AI, and AII were isolated from mangrove rhizospheric soil. Microscopic and biochemical characteristics of the isolates were studied. Both isolates showed PGP activities like phosphate solubilization, IAA, and ammonia production. A1 isolates tolerated salt concentration up to 0.5% and A2 till 2%. Seed germination parameters of uninoculated and isolate inoculated seeds under salt stress (0%, 0.1%, 0.2%, 0.3% and 0.4% of NaCl) were recorded. Salt stress significantly affected the germination traits. However, inoculation favored germination of mustard seeds in comparison to uninoculated ones under salt stress.
• Azotobacter isolates A1 and A2 exhibited plant growth-promoting features like Ammonia production, Phosphate solubilization, and Indole acetic acid production.
• Isolates A1 and A2 tolerated salt concentrations up to 0.5% and 2%.
• Germination of seeds not inoculated with Azotobacter isolates reduced significantly with increasing concentrations of salt.
• Bioinoculation with isolates A1 and A2 boosted germination of seeds under salt stress.
Indian mustard, Salt stress, Sustainable, Halotolerant, Azotobacter, Seed germination
