The plant-rhizobial symbiotic interactions provide benefits to the host beyond nitrogen fixation that promote plant growth and productivity


Habtewold, JZ and Goyal, RK. The plant-rhizobial symbiotic interactions provide benefits to the host beyond nitrogen fixation that promote plant growth and productivity. In: Everlon Rigobelo, Editor. Symbiosis in Nature. InTech Open Access; 2023. Pages 1-25

Plain language summary

The book chapter highlights the importance of a symbiotic interaction of legumes with Rhizobium that provides benefits to the host in addition to nitrogen fixation. The rhizobia possess the capability to synthesize plant growth hormones that boost the plant's growth. Also, the symbiotic bacteria enable the host to acquire iron and phospate nutrients from the soil, which are otherwise inaccessible to the host. Such benefits can be enhanced by selecting and modifying the symbiotic bacteria to improve the productivity of legumes. Leguminous crops are not only the drivers of economic growth in the Prairies but also enhance agriculture sustainability by reducing the carbon footprint.


Rhizobial symbiotic interactions are known for nitrogen fixation, providing
commercial crops and other plants with self-sufficiency in nitrogen requirements. An
enormous contribution from nitrogen fixation is vital to the global nitrogen cycle. The
symbiotic nitrogen reduces the carbon footprint of crop cultivation, which underlines
its importance in agricultural sustainability. Extensive research efforts have been
made to understand the symbiotic relationship at molecular, physiological, and
ecological levels. This led to the isolation and modification of symbiotic strains for
enhanced nitrogen efficiency. During the evaluation of strains for nitrogen fixation
in exchange for supporting the bacterium in terms of space and resources, it has been
observed that the accrued benefits to the host plants extend well beyond the nitrogen
fixation. The symbiotic interaction has been advantageous to the host for better
growth and development, tolerating a stressful environment, and even keeping the
pathogenic microbial enemies at bay. Additionally, it enabled the availability of the
mineral nutrients, which otherwise were inaccessible to the host. In this chapter, we
bring together the information with a focus on the role of rhizobial symbiotic interactions
that promote plant growth and productivity through phytohormone synthesis,
by facilitating the availability of mineral nutrients, and by improving the plant tolerance
to sub-optimal growth conditions.

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