Bacillus velezensis SYL-3 suppresses Alternaria alternata and tobacco mosaic virus infecting Nicotiana tabacum by regulating the phyllosphere microbial community

• Published in: Frontiers in microbiology Vol. 13; p. 840318
• Main Authors: Liu, He, Jiang, Jun, An, Mengnan, Li, Bin, Xie, Yunbo, Xu, Chuantao, Jiang, Lianqiang, Yan, Fangfang, Wang, Zhiping, Wu, Yuanhua
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 28-07-2022
• Subjects: Alternaria alternata; Bacillus velezensis SYL-3; Microbiology; Nicotiana tabacum; phyllosphere microbial community; tobacco mosaic virus
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2022.840318

The occurrence of plant diseases is closely associated with the imbalance of plant tissue microecological environment. The regulation of the phyllosphere microbial communities has become a new and alternative approach to the biological control of foliar diseases. In this study,
Bacillus velezensis
SYL-3 isolated from Luzhou exhibited an effective inhibitory effect against
Alternaria alternata
and tobacco mosaic virus (TMV). The analysis of phyllosphere microbiome by PacBio sequencing indicated that SYL-3 treatment significantly altered fungal and bacterial communities on the leaves of
Nicotiana tabacum
plants and reduced the disease index caused by
A. alternata
and TMV. Specifically, the abundance of
P. seudomo
,
Sphingomonas
,
Massilia
, and
Cladosporium
in the SYL-3 treatment group increased by 19.00, 9.49, 3.34, and 12.29%, respectively, while the abundances of
Pantoea
,
Enterobacter
,
Sampaiozyma
, and
Rachicladosporium
were reduced. Moreover, the abundance of beneficial bacteria, such as
Pseudomonas
and
Sphingomonas
, was negatively correlated with the disease indexes of
A. alternata
and TMV. The PICRUSt data also predicted the composition of functional genes, with significant differences being apparent between SYL-3 and the control treatment group. Further functional analysis of the microbiome also showed that SYL-3 may induce host disease resistance by motivating host defense-related pathways. These results collectively indicate that SYL-3 may suppress disease progression caused by
A. alternata
or TMV by improving the microbial community composition on tobacco leaves.