Impacts of different ozone treatments on the growth and soil bacterial community of Pinellia ternata.

Continuous cropping causes soil microbial imbalance, which severely reduces the yield and quality of medicinal plants. Ozone, a potent oxidant, has the potential to eradicate soilborne diseases in agricultural systems. However, the application of ozone to alleviate continuous cropping problems in the medicinal plant Pinellia ternata has not been reported. This study applied four treatments to P. ternata tubers and continuous cropping soil. The control treatment (CK) was not exposed to ozone and was irrigated with distilled water. The experimental treatments included ozone-fumigated tubers irrigated with distilled water (OS), ozone-unfumigated tubers irrigated with ozonated water (WO), and ozone-fumigated tubers irrigated with ozonated water (ZO). Compared with the CK treatment, the WO treatment significantly increased the germination rate, plant height and tuber fresh weight of P. ternata by 10-30%. In contrast, the chlorophyll content in the leaves of P. ternata decreased by 10-30% under OS and ZO compared with that under CK. Soil bacterial community analysis identified Pseudomonadota and Actinomycetota as the dominant bacterial phyla. Pseudomonadota constituted 30.1% in WO and 20.8% in ZO, whereas CK and OS accounted for 28.2% and 29.3%, respectively. At the genus level, beneficial taxa such as PSRF01 and Sphingomicrobium were significantly enriched in the WO treatment. The alpha diversity showed that the Chao1 and Faith indices were highest in the WO treatment, whereas the Simpson and Shannon indices peaked in OS treatment. Beta diversity analysis revealed no significant differences in bacterial community structure among WO, CK, and ZO treatments but significant differences relative to OS treatment. Functional profiling via FAPROTAX revealed that chemoheterotrophy and aerobic chemoheterotrophy presented the highest relative abundances in WO treatment. Additionally, compared with the CK treatment, the WO treatment increased the network connectivity at both the bacterial phylum and genus levels. In summary, WO treatment promoted the growth and development of P. ternata and increased bacterial diversity, thereby mitigating continuous cropping problems. Our study presents a novel technical strategy and theoretical foundation for the ecological cultivation of the medicinal plant Pinellia ternata.