Legume Root Nodules- evolutionary Adaptation for Improved Survival Mechanism
Roshni Vijayan *
College of Agriculture, Kerala Agricultural University, Vellanikkara, Kerala, India.
Jiji Joseph
College of Agriculture, Kerala Agricultural University, Vellanikkara, Kerala, India.
*Author to whom correspondence should be addressed.
Abstract
Root nodule symbiosis in leguminous plant belonging to Fabaceae family, represents a pivotal evolutionary innovation enabling a mutualistic relationship with nitrogen fixing bacteria. This trait vital for plant growth in nitrogen deficient soils, evolved within the Nitrogen Fixing Clade (NFC), particularly among subfamilies like Papilionoideae and Mimosoideae-Caesalpinieae-Cassieae clade, indicating multiple independent origins. Genetic studies emphasizing repeated evolutionary losses of nodulation across lineages. The development of root nodule symbiosis has been profoundly influenced by intricate mechanisms including horizontal gene transfer, reciprocal co-evolutionary dynamics between legumes and rhizobia and selective pressures exerted through the domestication of leguminous species. The translational potential of this research is exemplified through strategic achievements such as enhancing nitrogen use efficiency via genotype driven selection in leguminous crops like cowpea and soyabean and pioneering efforts to engineer root nodule symbiosis in non-leguminous crops like cereals. These applications are pivotal in fostering sustainable agricultural systems, particularly in nitrogen deficient soils. This review emphasis on a comprehensive understanding of the evolutionary and functional dynamics underpinning legume rhizobia symbiosis to guide future innovations aimed at promoting sustainable agriculture and ensuring long term food and nutritional security.
Keywords: Biological nitrogen fixation, co-evolution, horizontal gene transfer, nodulation, root nodule symbiosis (RNS)