Can the Endophytic Microbial Compositions in Tomato Roots be Reshaped by Application with Wood Vinegar Under Continuous Cropping System

Wood vinegar promotes crop growth and improves soil fertility and health. It is important to explore the mechanism by which wood vinegar promotes tomato growth under the continuous cropping system. Four wood vinegar treatments, i.e., the sterilized deionized water only (control, CK), and 300 times (A), 600 times (B) and 900 times (C) dilutions were set up, and the endophytic microbial compositions in the roots of tomatoes under the continuous cropping system using wood vinegar dilutions were analyzed. The results showed that the root morphological indices of tomatoes grown under continuous cropping systems were improved by different wood vinegar applications. In comparison with the CK, 600 times wood vinegar dilution increased the endophytic bacterial (and fungal) Shannon and ACE indices by 14.04% (19.41%) and 23.61% (18.37%), respectively. And some plant growth-promoting bacteria, such as Bacillus, Pseudolabrys, Burkholderia-Caballeronia-Paraburkholderia, colonized and grew in tomato roots after applying wood vinegar dilutions under the continuous cropping system. In addition, some pathogens, such as Acrocalymma and Dactylonectria, were missed or decreased in tomato roots after applying of wood vinegar dilution under the continuous cropping system. In particular, the best effect of wood vinegar on reducing pathogens in tomato roots under a continuous cropping system was 600 times dilution. These results suggest that not only the endophytic microbial compositions but also their functions in tomato roots under a continuous cropping system could be reshaped by wood vinegar dilution application.