Microorganisms regulate soil phosphorus fractions in response to low nocturnal temperature by altering the abundance and composition of the pqqC gene rather than that of the phoD gene

Low nocturnal temperature (LNT) is a primary limitation in the greenhouse cultivation of vegetables during winter and spring, because it limits the availability of soil phosphorus (P), causing P-deficient symptoms. However, how LNT affects the P-cycling-related bacterial community composition and the turnover of soil P fractions is unknown. To address this issue, a 40-day indoor incubation experiment was used to investigate the effects of four nocturnal temperatures (15 °C, 12 °C, 9 °C, and 6 °C) on soil P fractions, alkaline phosphomonoesterase (ALP) activity, and the absolute abundance and composition of phoD - and pqqC -harboring microbial community. The low temperature decreased labile inorganic P (LPi) and increased labile organic P (LPo) and moderately labile Pi and Po (MLPi, MLPo). Low temperature decreased phoD and pqqC gene absolute abundance while increasing pqqC -harboring bacterial richness. The classes Actinobacteria , Alphaproteobacteria , and Betaproteobacteria dominated the phoD - and pqqC -harboring taxa in response to low temperature, despite low temperature, which decreased the absolute abundance of the phoD gene, potentially decreasing NaHCO 3 -Po and NaOH-Po mineralization. Moreover, low temperature influenced pqqC gene absolute abundance and pqqC -harboring bacterial community composition, likely decreasing NaOH-Pi solubilization. However, the soil LP and MLP fractions were only significantly correlated by pqqC gene absolute abundance and pqqC -harboring community composition.