Suppression of Fusarium Wilt Caused by Fusarium oxysporum f. sp. lactucae and Growth Promotion on Lettuce Using Bacterial Isolates

Identification and Surveys of Promoting Plant Growth VOCs from Biocontrol Bacteria Paenibacillus peoriae GXUN15128

The role of microbial volatile organic compounds (MVOCs) in promoting plant growth has received much attention. We isolated Paenibacillus peoriae from mangrove rhizosphere soil, which can produce VOCs to promote the growth of Arabidopsis thaliana seedlings, increase the aboveground biomass of A. thaliana, and increase the number of lateral roots of A. thaliana. The effects of different inoculation amounts and different media on the composition of MVOCs were studied by solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) and headspace sampler/GC-MS. We found that the growth medium influences the function and composition of MVOCs. To survey the growth-promoting functions, the transcriptome of the receptor A. thaliana was then determined. We also verified the inhibitory effect of the soluble compounds produced by P. peoriae on the growth of 10 pathogenic fungi. The ability of P. peoriae to produce volatile and soluble compounds to promote plant growth and disease resistance has shown great potential for application in the sustainability of agricultural production. IMPORTANCE Microbial volatile organic compounds (MVOCs) have great potential as "gas fertilizers" for agricultural applications, and it is a promising research direction for the utilization of microbial resources. This study is part of the field of interactions between microorganisms and plants. To study the function and application of microorganisms from the perspective of VOCs is helpful to break the bottleneck of traditional microbial application. At present, the study of MVOCs is lacking; there is a lack of functional strains, especially with plant-protective functions and nonpathogenic application value. The significance of this study is that it provides Paenibacillus peoriae, which produces VOCs with plant growth-promoting effects and broad-spectrum antifungal activity against plant-pathogenic fungi. Our study provides a more comprehensive, new VOC component analysis method and explains how MVOCs promote plant growth through transcriptome analysis. This will greatly increase our understanding of MVOC applications as a model for other MVOC research.

Comparative genomic and functional analyses of Paenibacillus peoriae ZBSF16 with biocontrol potential against grapevine diseases, provide insights into its genes related to plant growth-promoting and biocontrol mechanisms

Paenibacillus peoriae is a plant growth-promoting rhizobacteria (PGPR) widely distributed in various environments. P. peoriae ZBFS16 was isolated from the wheat rhizosphere and significantly suppressed grape white rot disease caused by Coniella vitis. Here, we present the complete genome sequence of P. peoriae ZBFS16, which consists of a 5.83 Mb circular chromosome with an average G + C content of 45.62%. Phylogenetic analyses showed that ZBFS16 belongs to the genus P. peoriae and was similar to P. peoriae ZF390, P. peoriae HS311 and P. peoriae HJ-2. Comparative analysis with three closely related sequenced strains of P. peoriae identified the conservation of genes involved in indole-3-acetic acid production, phosphate solubilization, nitrogen fixation, biofilm formation, flagella and chemotaxis, quorum-sensing systems, two-component systems, antimicrobial substances and resistance inducers. Meanwhile, in vitro experiments were also performed to confirm these functions. In addition, the strong colonization ability of P. peoriae ZBFS16 was observed in soil, which provides it with great potential for use in agriculture as a PGPR. This study will be helpful for further studies of P. peoriae on the mechanisms of plant growth promotion and biocontrol.