Soil bacterial community recruits Sphingomonas to reduce abiotic stress in continuous tobacco

Different planting patterns alter soil bacterial communities by altering soil environmental factors, but how changes in planting pattern affect interactions between bacterial communities and soil environmental factors is poorly understood. An experiment was conducted in continuously cropped and rotated tobacco to determine how differences in planting pattern affected interactions between soil bacterial communities and soil chemical properties, enzyme activities, and phenolic acids. Compared with crop rotation, available potassium (K) and available phosphorus (P) increased, nitrate nitrogen (N) and hydrolysed N decreased, phenolic acids accumulated, and invertase activity decreased under continuous cropping. Complexity of bacterial ecological networks was lower under continuous cropping than under crop rotation. A linear discriminant analysis effect size analysis indicated that Sphingomonas was the critical genus in the soil bacterial community under continuous cropping. Pearson correlations and Mantel tests showed that soil available K, available P, hydrolysed N, available N, invertase activity, and phenolic acids were significantly correlated with Sphingomonas. Therefore, long-term continuous cropping of tobacco led to soil nutrient imbalance, phenolic acid enrichment, and reduced invertase activity, and we hypothesize those changes reduced soil bacterial community complexity and thus promoted the recruitment of Sphingomonas to improve tolerance to abiotic stresses.