Differential recruitment of root bacterial community by inoculated inland spiny and spinless cactus in response to salinity stress

In the field of innovative challenges, it is essential to incorporate microorganisms into agricultural practices that promote and improve plant growth and health, particularly under conditions of salinity stress. This work elucidated the response of two Opuntia ficus-indica cultivars (spiny, Gialla and spineless, Rossa) inoculated inland with a coastal cactus rhizospheric soil (Opuntia littoralis) under NaCl treatment. The two cultivars reacted differently to salinity stress. The cladodes and roots of the Rossa cultivar were sensitive to salinity and accumulated both Na⁺ and Cl⁻. In contrast, the Gialla cultivar showed Na ⁺ exclusion from the cladodes and root growth was unaffected by salinity. The diversity, richness, and correlation networks of root compartments bacterial communities were mainly determined while the cactus cultivar was subjected to salinity stress. Different subsets of key soil bacteria taxa were selected by the root systems of each cultivar after exposure to salinity. Our results highlight the importance of the rhizosphere of endemic coastal plants in improving plant resistance to salinity stress, particularly in the spiny cultivar compared to the spineless cultivar. The microbiome networks provide solid evidence that each cultivar adapts its bacterial community composition and interactions in response to salinity.