Diversity and Functional Potential of Rhizosphere Microorganisms Across Tea Cultivars, with a Focus on Their Heavy Metal Resistance and Aluminum Tolerance

Abstract

Rhizosphere microbes play a critical role in plant stress adaptation; however, the diversity and functional potential across different tea cultivars remain poorly understood. Here, we employed high-throughput sequencing and fungal isolation across five distinct tea cultivars (cv. A–E). Our results reveal significant divergence among the sampled tea populations: Mucoromycota-dominated communities with higher diversity were observed in cultivars A, B, and C, whereas Ascomycota-dominated communities with lower diversity characterized cultivars D and E. Concomitantly, bacterial heavy MRGs profiles exhibited a parallel dichotomy, with Cd/Zn/Co/As/Mn-related resistance functions enriched in cultivars A, B, and C and Ni/W/Mo-related functions enriched in cultivars D and E. Spearman correlation analysis demonstrated that these divergent MRGs profiles were significantly associated with soil characteristics, such as Ex Al and OM, but not with pH, indicating that edaphic filtering independently shapes bacterial functional potential in the tea rhizosphere. Furthermore, four fungal isolates (L3, L4, L5, and L19) exhibited robust Al tolerance and multiple in vitro plant growth-promoting traits. These findings highlight the tea rhizosphere as a complex environment that drives parallel differentiation in fungal community structure and bacterial resistance gene profiles, providing a foundation for the development of microbial strategies to enhance stress adaptation in acidic tea agroecosystems.