Symbiotic Rhizobia, Nitrogen Fixation, and Fenugreek

Abstract

Leguminous fenugreek (Trigonella foenum-graecum L.) has enormous economic and medicinal value. It is widely cultivated in South Asia, North Africa, and the Mediterranean region for its seeds, leaves, and roots used in cooking, herbal medicine, and cosmetics. Fenugreek grows well in soils deficient in nitrogen, making it a prime candidate for research into the potential advantages of rhizobia inoculation. The conversion of atmospheric nitrogen into forms that plants can use can significantly increase plant yield and growth. The symbiotic relationship between fenugreek and rhizobia carries out this process. Rhizobia is a group of soil bacteria that can fix atmospheric nitrogen and transform it into a usable form for the plant. Rhizobia can thrive and perform nitrogen fixation in a specialized environment that legume plants offer in the form of root nodules. Significant effects on sustainable agriculture and food security result from the rise in soil fertility and plant productivity. Also, rhizobia inoculants can further improve fenugreek plant growth, yield, and nitrogen fixation, according to recent studies. The most suitable inoculant strain must be chosen, and the inoculation procedure must be optimized, for the inoculation to be successful. For symbiosis to develop, rhizobia and leguminous plants must be compatible with one another. Flavonoid-like, specific signals from the plant draw rhizobia to the root system. Rhizobia produces nodulation factors in response to these signals, which encourage the development of root nodules. Rhizobia undergoes morphological and physiological changes once they are inside the nodules, turning into nitrogen-fixing bacteroids. The bacteroids then convert atmospheric nitrogen into ammonia. The plant can use the ammonia the bacteroids produce to grow and synthesize proteins. Establishing rhizobial inoculation in fenugreek depends heavily on the inoculant strains used. The capacity of an inoculant strain to outcompete local rhizobia in the soil and its compatibility with the plant determine its efficacy. Rhizobia strains that can improve nitrogen fixation and plant growth in fenugreek have been identified and characterized. The ability of these strains to boost plant biomass, seed yield, and nitrogen content has been demonstrated. The effectiveness of rhizobial inoculation in fenugreek is also greatly influenced by the timing and technique of the inoculation. The sowing or transplanting period is the ideal time to inoculate fenugreek. The inoculation method can change depending on the type of inoculant and the planting technique. The three methods of vaccination used presently are seed coating, soil inoculation, and foliar spray. The cost, effectiveness, and efficiency of the method are a few variables influencing which inoculation method is most suitable. Environmental factors like soil pH, temperature, moisture, and salinity can also influence the effectiveness of rhizobial inoculation in fenugreek. Moisture and temperature significantly impact the growth and survival of rhizobia. Low temperatures and high moisture can increase the risk of disease, while high temperatures and low moisture can reduce the survival of rhizobia. © 2026 by Apple Academic Press, Inc.