Impact of plant pathogens on potato rhizosphere enzymes and microbial dynamics

Gaihuan Xu ¹ Linmei Deng ² Jian Dao ² Wenping Wang ² Chunjiang Liu ² Yanli Yang ^2* Jing Zhao ^2* Xia Liu ^2*

• ¹ Agricultural Environment and Resources Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, Yunnan Province, China
• ² Yunnan Agricultural University, Kunming, China

Soilborne pathogens significantly impact potato (Solanum tuberosum L.) productivity by altering rhizosphere enzymatic activities and microbial communities. Pathogen-induced changes in enzyme activities were correlated with shifts in microbial community composition, though causal relationships require further investigation. This study investigated the effects of five key pathogens, including Phytophthora infestans, Streptomyces scabies, Spongospora subterranea, Ralstonia solanacearum, and Globodera rostochiensis on soil enzyme activities and microbial community structure in potato rhizosphere soils under continuous cropping. P. infestans was studied for its indirect effects on soil dynamics following foliar infection, rather than as a primary soilborne pathogen. Each treatment was replicated three times, planting on March 22, 2023, and harvested on August 25, 2023. Enzymatic activities were measured during different growth stages, and microbial communities were analyzed using high-throughput sequencing. The results revealed pathogen-induced variations in enzymatic activities, potentially promoting disease proliferation. For example, under S. scabies stress, URE activity in the soil during the full flowering and post-flowering stages increased from 161.36 and 204.69 to 197.10 and 274.27 μg•(g•24h) -¹, representing significant increases of 22.1% and 34.0%, respectively. Conversely, CAT activity in the rhizosphere soil decreased significantly by 0.54 and 1.51 mg•(g•20min) -¹ during the seedling and full flowering stages, respectively. Under S. subterranea stress, the activities of soil urease, SUC and ALP exhibited a decreasing trend. Notably, sucrase activity declined by 1.47 and 2.78 mg•(g•24h) -¹ during the initial flowering and harvest stages, respectively. Exposure to M. nematode stress led to a decline in URE activity, with levels decreasing from 295.58 and 202.83 to 277.59 and 188.25 μg•(g•24h) -¹ at the sowing and harvest stages, respectively. Similarly, sucrase activity was reduced from 31.36, 12.67, and 13.49 to 14.01, 11.62, and 13.03 mg•(g•24h) -¹ during the sowing, seedling, and initial flowering stages, respectively. Following P. infestans infection, URE activity at the sowing stage declined by 104.57 μg•(g•24h) -¹ compared to the control. Additionally, significant correlations were observed 字体: (默认)Times New Roman,