Straw-Mediated Restructure of Arbuscular Mycorrhizal Fungal Community by Selectively Shifting Edaphic Biogeochemistry in Tea Plantations of South Henan, China

Background: Straw application (SP) is an important agronomic practice in sustainable agriculture, yet its effects on arbuscular mycorrhizal (AM) fungal communities in tea plantation soils remain poorly understood. Methods: This study investigated the responses of AM fungi to SP in tea plantations in south Henan, China, by assessing colonization characteristics, community composition, diversity, co-occurrence networks, and soil environmental drivers. Results: SP significantly increased the mycorrhizal colonization rate (MC), by 59.4%. High-throughput sequencing (26,865 sequences and 406 ASVs) revealed that SP reduced the dominance of Claroideoglomus (32.2% to 10.5%) and Glomus (51.01% to 46.7%) while enriching Paraglomus and Acaulospora. Although the α-diversity was unaffected, the β-diversity significantly shifted, indicating community homogenization under SP. Differential taxa analysis confirmed genus-specific responses, and co-occurrence networks showed a simplified topology (nodes: −18.4%; edges: −33.4%) but maintained stability, with increased module specialization (Zi and Pi). Soil properties explained 80.0% of the variation in AM fungal parameters, with pH and available phosphorus (AP) as key drivers. SP shifted environmental filters from nitrogen/carbon-related factors to metal ions (Al3+ and Ca2+), altering geochemical conditions. Conclusions: SP selectively reshapes AM fungal communities by altering soil microenvironments and selectively modulating the AM fungal community while maintaining network stability. This study provides new insights into the microbial mechanisms of SP and a basis for sustainable, AMF-based tea plantation management.