Linking root-associated fungal communities, wheat evolutionary patterns, and productivity: overlooked roles of rare taxa

Abstract Background and Aims The intricate relationships between root-associated fungal communities and wheat plants can potentially impact plant health, crop yield, and quality. However, the interplay among various wheat varieties, fungal communities, and wheat productivity remains understudied. Methods In this study, 95 wheat varieties in China were selected. Plant and soil samples were collected during two wheat growth stages (regreening and heading). DNA extraction and genotyping were performed, and fungal ASVs were categorized based on abundance. Fungal community diversity, assembly mechanisms, and relationships were examined. Co-occurrence networks were used to identify keystone taxa. Relationships between wheat genetics, quality, yield, and fungal communities were assessed. Broad-sense heritability ( H 2 ) of root-associated ASVs was calculated. Results Abundant and core taxa significantly influenced fungal community structure, with stochastic processes mainly driving the assembly. Regreening stage's rhizosphere harbored keystone taxa, though a weak but meaningful connection existed between wheat genetic distance and rare taxa at the heading stage. Wheat quality and yield were significantly ( P < 0.05) influenced by rare rhizosphere taxa during regreening stage, while heading stage yield correlated positively with keystone taxa and Glomeromycota. Rhizosphere abundant subcommunity was more specialized in enriching taxa with low and moderate heritability, while rare subcommunity was better at recruiting high-heritability ( H 2 > 0.4) taxa. Conclusions Abundant and core taxa played a substantial role in shaping fungal communities during wheat growth, but less abundant rhizosphere species were also vital, as they attained keystone status, showed genetic ties to the host, and were related to wheat quality and yield with higher heritability.