Background

Plant-associated microorganisms can enhance crop growthresilience to environmental stressors. Maize (Zea mays L.) selectively recruits beneficial microbes under saline–alkali stress; however, the interplay between maize genotypic variationmicrobial community dynamics remains poorly understood. Here, we compared the structure, diversity,functional potential of root-associated microbial communities across eight maize inbred lines differing in saline–alkali tolerance.

Results

Compared with the saline–alkali-sensitive lines, the saline–alkali-tolerant lines exhibited significantly higher plant biomassless leafroot damage. Microbial communities in tolerant lines exhibited greater diversitymore complex co-occurrence networks, showing inferred functional enrichment in energy metabolismantioxidant pathways. Genotype-specific recruitment of the beneficial bacteria (Luteolibacter, Agromyces,Luteimonas)selective enrichment of Ascomycotaputative endomycorrhizal fungi across the rhizosphere–root interface could collectively enhance host tolerance through improving nutrient mobilization, pathogen resistance,stress mitigation. Moreover, we uncovered significant cross-compartmental co-occurrence patterns withinbetween bacterialfungal communities,revealed that saline–alkali-tolerant maize genotypes recruit functionally complementary microbiomes along the soil–root continuum. Aboveground traits appeared to shape community structure, whereas root endophytic bacteria were predicted to be linked to soil salinity,fungi were associated with host plant stress tolerance.

Conclusions

These findings advance our understanding of genotype-dependent plant–microbe interactions under saline–alkali stressprovide actionable targets for the development of microbial inoculants for sustainable agriculture.