Microbial network and composition changes according to tobacco varieties and interferes differently in black shank disease defense.

AIMS: The soil-borne oomycete pathogen Phytophthora parasitica can cause black shank disease in tobacco plants. The use of resistant varieties can be used to control black shank disease. The potential relationships of the composition of the rhizosphere microbiome to resistance to black shank disease are poorly understood. This work aims to compare the rhizosphere microbial community and network of the tobacco resistant variety HB202 with the susceptible variety XY3. METHODS AND RESULTS: Rhizospheric soils were collected from tobacco plants of HB202 and XY3 in the fields with same soil types and agricultural operations. The compositions of the rhizosphere microbial communities were revealed by Illumina sequencing of bacterial 16S rRNA genes and fungal spacer (ITS) sequences and analysed with molecular ecological network pipeline. The alpha diversity of fungal communities of the two varieties was significantly different. The structure and composition of bacterial and fungal communities in the resistant variety in the rhizosphere was different from the susceptible variety. Relative abundances of beneficial genera in the HB202 microbiota were higher than in the XY3. Conversely, the XY3 microbiota exhibited a higher abundance of deleterious genera compared to the HB202 microbiota. The resistant variety influences the topological properties and microbial interactions in the rhizosphere against the disease. The network of the HB202 was more complex and had higher connectivity compared to the XY3 network. CONCLUSIONS: The rhizosphere microbial communities and networks of two tobacco varieties are very different. These changes in the microbial communities and their interactions may play an important role in tobacco resistance to black shank disease.