Analysis of Rhizosphere Microbial Diversity Among Different Maize Varieties in the Hexi Corridor

Rhizosphere microorganisms have a significant impact on plant growth and development. To clarify the regulatory mechanisms underlying maize genotype effects on rhizosphere soil physicochemical factors and microbial communities in the Hexi Corridor of China, this study used seven maize varieties (Wugu 305, Xianyu 335, Zhengdan 958, Jingke 968, Yufeng 303, Dedan 1104, and Qinfeng 876) as experimental materials. Rhizosphere soil physico-chemical indicators were measured, and high-throughput sequencing was used to analyze the diversity, structure, unique bacterial communities, and metabolic functions of rhizosphere fungi and bacteria. Correlation analysis was also conducted using soil environmental factors. The results showed that the pH of the tested maize rhizosphere soil was weakly alkaline (7.96–8.10); significant varietal differences were observed in total nitrogen, available nitrogen, and available phosphorus, while no significant differences were observed in organic matter and total phosphorus among maize varieties. Dedan 1104 and Jingke 968 had the highest fungal richness, diversity, and evenness at the phylum and genus level, according to an alpha-diversity study of maize rhizosphere soil microorganisms, which revealed that variation did not affect fungal community richness. Zhengdan 958 has the highest microbial richness at the bacterial phylum level. At the bacterial genus level, Dedan 1104 had the highest microbial abundance. Ascomycota is the predominant fungal phylum, with Proteobacteria, Acidobacteria, and Chloroflexi being the core bacterial phyla. Venn analysis confirmed strong conservation of fungal community composition across various maize varieties; abundant bacterial-specific taxa and greater genotype-driven differentiation. Furthermore, significant differences were found in the enriched microbial communities in the rhizosphere among different maize genotypes, with fungal metabolic functions strongly influenced by maize genotype, and the distribution of core bacterial functional enzymes tending towards homogeneity. Available phosphorus and alkaline-available nitrogen were the core environmental factors regulating the structure of rhizosphere fungal and bacterial communities, and the dominant functional microorganisms were significantly positively correlated with these nutrients. This study provides a theoretical basis for screening high-quality seed maize varieties and regulating rhizosphere soil microecology.