Impact of genotype and soil fertility on wheat rhizosphere microbiota under the trans-gangetic plain

The effects of genotypes (HD3086 and PBW343) and soil physicochemical properties on the wheat rhizospheric bacterial communities along the trans Indo-Gangetic plains were studied. The trans-Indo-Gangetic Plains of India are one of the areas in the country where wheat is grown the most. Despite the agricultural significance of this region, extensive studies on the rhizosphere microbial abundance and community structure related to wheat cultivation in this area are still lacking. To address this knowledge gap, the present study was undertaken to characterize the rhizosphere microbiome using full-length 16 S rRNA-based metagenomic profiling, implementing universal primers, tailed with PacBio Sequel II barcode sequences, providing new insights into microbial dynamics across this major wheat-producing landscape. Statistical analysis revealed significant differences in both abundance and diversity among the different soil samples and wheat genotypes. Four phyla exhibited significant differences in relative abundance between the genotypes (p < 0.05): Proteobacteria (p = 0.002), Planctomycetes (p = 0.000), Verrucomicrobia (p = 0.000), and Firmicutes (p = 0.030). The number of genera identified in genotype HD3086 across all locations was 421, while it was 322 for genotype PBW343. There were 251 genera found common, with 170 genera exclusively present in HD3086 and 71 in PBW343. Significant differences were observed in the relative abundance of eighteen genera (p < 0.05) between the genotypes; some of them include Luteolibacter, Gemmata, Pseudomonas, Stenotrophobacter, Pseudarthrobacter, Devosia, Lacibacter, Gaiella, Luteimonas, and Nitrosospira. Correlation analysis indicated significant associations between microbial diversity and soil parameters like pH, total and available nitrogen, potassium, phosphorus, iron, and organic carbon for both varieties. Core taxa analysis revealed 27 core taxa across both genotypes. The study highlights significant genotype effects on rhizosphere microbiomes, with implications for soil health and crop management strategies.