PT - JOURNAL ARTICLE AU - Dongsheng Guo AU - Chenhong Yuan AU - Yunyan Luo AU - YaHan Chen AU - Meihuan Lu AU - Guochan Chen AU - Guangwei Ren AU - Chuanbin Cui AU - Jiatao Zhang AU - Derong An TI - Biocontrol of PGPR strain <em>Bacillus amyloliquefaciens</em> Ba168 against <em>Phytophthora nicotianae</em> on tobacco AID - 10.1101/700757 DP - 2019 Jan 01 TA - bioRxiv PG - 700757 4099 - http://biorxiv.org/content/early/2019/07/14/700757.short 4100 - http://biorxiv.org/content/early/2019/07/14/700757.full AB - Tobacco black shank (TBS) caused by Phytophthora nicotianae is destructive to almost all kinds of tobacco cultivars and is widespread in many tobacco-planted countries. Here, an isolated plant growth-promoting rhizobacteria (PGPR) strain Ba168 is promise in biocontrol of TBS. In vitro assays disclosed a strong P. nicotianae suppression activity and the field utilization potential (FUP) by characterized the crude extract of culture filtrates of Ba168. P. nicotianae’s growth was inhibited by the crude extract at minimum inhibitory concentration (MIC) of 5μl/mL. Extracellular conductivity, pH and the wet, dry weight of P. nicotianae’s mycelia, were significantly different after treated with different concentrations of the crude extract and the deformity and perforation of treated P. nicotianae’s hyphae can be observed in scanning electron microscope (SEM) analysis. Proteome characterizations of the crude extract were used as supplementary proofs that further evaluated FUP of Ba168. We then identified strain Ba168 as B. amyloliquefaciens by its genetic and phenotypic characteristics. Field assays comparatively evaluated TBS control efficacy of these PGPRs and agrochemicals. Pooling analysis of the results showed that the biocontrol efficacy of Ba168 preparation is only lower than Mixture of Propamocarb hydrochloride and Azoxystrobin (MPA) but better than other tested subjects. Although the existence of differences in biocontrol efficacy, PGPR preparations effectively reduced the disease index of tobacco.Importance This work demonstrates the promising biocontrol potential of B. amyloliquefaciens Ba168 and highlights the positive roles of PGPR in suppression of this soil-borne disease.