Archives

Indian Journal of Pure & Applied Biosciences (IJPAB)
Year : 2020, Volume : 8, Issue : 5
First page : (98) Last page : (114)
Article doi: : http://dx.doi.org/10.18782/2582-2845.8256

Search for the Holy Grail: Rhizobium

Harleen Kaur Talwar^1* and Anshu Sibbal Chatli^2
1Department of Biotechnology and ²Department of Microbiology
Guru Nanak Girls College, Model Town, Ludhiana
*Corresponding Author E-mail: harleenk9902@gmail.com
Received: 12.07.2020 | Revised: 19.08.2020 | Accepted: 23.08.2020 

 ABSTRACT

Legume-Rhizobia symbiosisis of the great ecological and agronomic importance, due to their ability to fix a large amount of atmospheric nitrogen (360 Kg of N per hectare per year). Enzyme nitrogenase plays an important role in fixation of nitrogen. Acetylene reduction assay is used to measure the nitrogenase activity. Rhizobium gets attached to root hair by lectin mediated hypothesis resulting in curling of root hair, formation of infection threads followed by critical cells division. Further bacteria also divides and redivides giving rise to bacteroids surrounded by leghaemoglobin. This leghaemoglobin binds with oxygen giving rise to oxyleghaemoglobin proving anaerobic conditions within for the fixation of nitrogen. The behaviour of some nitrogen fixing systems under severe environmental conditions such as salt stress, drought stress, acidity, alkalinity, nutrient deficiency, fertilizers, heavy metals and pesticides is reviewed. These major stress factors suppress the growth and symbiotic characterstic of most Rhizobia. However, several strains, distributed among various species of Rhizobia, are tolerant to stress effects. Specific strains of Rhizobia are required to make the nodules functional in order to carry out the process. This increases the yield of crops.

Keywords: Legumes, Rhizobia, Leghaemoglobin, Stress.

Full Text : PDF; Journal doi : http://dx.doi.org/10.18782

Cite this article: Talwar, H.K., & Chatli, A.S. (2020). Search for the Holy Grail: Rhizobium, Ind. J. Pure App. Biosci. 8(5), 98-114. doi: http://dx.doi.org/10.18782/2582-2845.8256