Figure 2

Hypothetical mechanism of action of biofertilizers in the root cell. Bioactive ligands called Myc factors and Nod factors secreted by mycorrhiza and Rhizobium were perceived by host roots to trigger the signal transduction pathway [106, 107], which initiates further signal transduction pathway through unknown receptors (SYMRK and NORK) [101] which trigger release of Ca²⁺ in the cytosol [108]. The whole pathway involves receptor like kinases or other kinase related proteins like DMI and SYM71 to phosphorylate their substrates [123, 124]. Nuclear pore complex (NPC) and some of its proteins (NUP) play role in calcium spiking. DM1 proteins play role in maintaining periodic oscillation of calcium ions inside and outside the nucleus. Several channels proteins (Ca²⁺channel proteins) also facilitate this process with the help of various transporters [108]. CCaMK is a calcium calmodulin-dependent protein kinase, which phosphorylate the product of CYCLOPS protein thus initiating activation of various genes involving formation of structures like nodule and (PPA) pre-penetration apparatus [124].