The effects of soil acidification on the phoD-harboring microbial community and the fractions of soil phosphorus in tea plantation soils are still unclear. In this study, tea plantations with different soil pH were used as the research object to analyze changes in soil phosphorus fractions, phoD gene abundance, phoD-harboring microbial community composition, and their relationship with tea yield and quality. The results showed that the content of tea polyphenols, caffeine, free amino acids, theanine, and tea yield decreased significantly after acidification. Moreover, the content of total phosphorus in the acidified soil also decreased significantly. Further analysis of soil phosphorus fractions showed that the acidification of the tea plantation soil resulted in a significant decrease in the content of different types of labile and moderately labile phosphorus, whereas the content of non-labile phosphorus exhibited the opposite trend. As the content of soil NaHCO₃-Po, NaOH-Po, Resin-Pi, NaHCO₃-Pi, NaOH-Pi, and HCl-Pi decreased significantly after acidification, its organic and inorganic phosphorus content also decreased significantly. Its phosphorus activation capacity decreased by 4.75% after soil acidification. Soil acidification significantly reduced the diversity of phoD-harboring microbial communities by 61.89%. Analysis of the phoD-harboring microbial community composition suggested that the microbial abundance of Acidobacteria and Proteobacteria showed a decreasing trend in acidified soils, while for Nitrospirae, Verrucomicrobia, Actinobacteria, and Planctomycetes, it showed an increasing trend. Correlation analysis showed that microorganisms with significantly decreasing abundance in tea plantation soils were significantly and positively correlated with soil pH, labile phosphorus, moderately labile phosphorus, phosphorus activation coefficients, and tea yield and quality after soil acidification. It is evident that soil acidification inhibited soil phosphorus availability by shifting phoD-harboring microbial community composition in tea plantation soils, thus affecting the yield and quality of above-ground tea leaves.

Space-induced mutation is a novel approach in tea plant breeding, but its effect on processing-induced aroma formation remains unclear. This study analyzed the dynamic changes in VOCs during the processing of space-induced mutants of Dahongpao tea. The results showed that processing significantly reshaped the VOC profile, with the fermentation stage exerting the greatest impact and terpenoids serving as the major contributors. Seven characteristic VOCs (α-phellandrene, β-phellandrene, d-sylvestrene, iso-geraniol, seudenone, hexyl benzene, and nerol) were identified and a transformation network linking floral, green, woody, almond, and fruity attributes was constructed. Molecular docking revealed that VOCs exhibiting green, woody and almond characteristics could form strong binding interactions with more than 100 olfactory receptors, whereas those with floral and fruity characteristics bound to fewer receptors. This finding indicates that during the processing, the first three odor characteristics may be perceived more prominently. Overall, this study provided a theoretical basis for the aroma evaluation of space-induced mutant tea.