Use of Bacillus velezensis SDTB022 against tobacco black shank (TBS) and the biochemical mechanism involved

Phytophthora nicotianae causes black shank, a serious soil-borne disease, in tobacco. In this study, the Bacillus strain GUMT319 was isolated from the rhizosphere of healthy tobacco plants grown in a field in Guizhou with a high incidence of tobacco black shank. Genome sequencing revealed that GUMT319 contained a single circular chromosome 3,940,023 bp in length, with 4,053 predicted genes and an average GC content of 46.6%. Based on phylogenomic analyses, GUMT319 was designated as Bacillus velezensis. The genome of GUMT319 contained more than 60 genes and 13 gene clusters that have previously been found to be active in antifungal mechanisms, biofilm formation, and chemotaxis motility. Additionally, confocal laser scanning microscopy and scanning electron microscopy showed that GUMT319 formed a spatially organized biofilm in vivo. In addition, lauric acid negatively regulated biofilm formation. This is the first study to report that nicotine in tobacco root exudates was a chemoattractant for biocontrol Bacillus strains. In this study, we identified new interactions between beneficial microorganisms and tobacco roots in the rhizosphere. Moreover, dual culture tests in vitro showed that GUMT319 inhibited the growth of P. nicotianae and also displayed inhibitory effects against eight other plant pathogens, namely, Colletotrichum scovillei, Colletotrichum capsici, Fusarium carminascens, Sclerotinia sclerotiorum, Alternaria alternata, Phomopsis sp., Phyllosticta sorghina, and Exserohilum turcicum. Furthermore, GUMT319 exhibited > 70% control efficiency against tobacco black shank in field experiments conducted in 2018–2020. Thus, GUMT319 was more effective in controlling the incidence of tobacco black shank than other treatments including fungicide application. Overall, these results suggested that GUMT319 (B. velezensis) could be used as a potential biocontrol agent against tobacco black shank.

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Management of the Tobacco Black Shank-Root-Knot Complex with Combinations of Soil Fumigants and Metalaxyl

Plant Disease ◽

10.1094/pd-78-0565 ◽

1994 ◽

Vol 78 (6) ◽

pp. 565 ◽

Cited By ~ 1

Author(s):

A. S. CSINOS

Keyword(s):

Black Shank ◽

Soil Fumigants ◽

Tobacco Black Shank

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Influence of Temperature and Rainfall on the Development of Tobacco Black Shank

Phytopathology ◽

10.1094/phyto-73-139 ◽

1983 ◽

Vol 73 (2) ◽

pp. 139 ◽

Cited By ~ 7

Author(s):

W. R. Jacobi

Keyword(s):

Black Shank ◽

Influence Of Temperature ◽

Tobacco Black Shank

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Prickly Ash Seed Kernel: A New Bio-Fumigation Material Against Tobacco Black Shank

Agronomy ◽

10.3390/agronomy10060770 ◽

2020 ◽

Vol 10 (6) ◽

pp. 770

Author(s):

Yaochen Wang ◽

Minghong Liu ◽

Xiaobin Han ◽

Yanfen Zheng ◽

Jianmin Chao ◽

...

Keyword(s):

Octadecadienoic Acid ◽

Solid Phase ◽

Vaccenic Acid ◽

Phytophthora Nicotianae ◽

Gas Chromatography Mass Spectrometry ◽

Hexadecenoic Acid ◽

Seed Kernel ◽

Higher Plant ◽

Black Shank ◽

Tobacco Black Shank

The present study evaluated the fumigant effect and potential mechanisms of Chinese prickly ash seed kernel (PSK) against tobacco black shank caused by Phytophthora nicotianae Breda de Haan. The results showed that PSK fumigant increased the soil organic matter, hydrolysable nitrogen, available potassium, and total phosphorus significantly, while the pH was decreased. Application of 2% PSK promoted plant growth, with higher plant height, root length, and dry weight compared to those in the treatment with no PSK. Both in vitro and in vivo tests indicated that PSK fumigant effectively inhibited mycelial growth of P. nicotianae, and significantly reduced the severity of tobacco black shank. Based on the analysis of volatiles in PSK by headspace solid-phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS), 28 components were identified, among which monoterpenes were the major components (accounting for 79.46% of peak area). Among the six top components, linalool, piperitone, sabinene, and limonene exhibited strong mycelial inhibition of P. nicotianae. Linalool was the most effective with an IC50 value of 18.03 μL/L. Results of GC-MS revealed that the main components of PSK extract were cis-Vaccenic acid (40.81%), n-Hexadecanoic acid (15.67%), 9,12-Octadecadienoic acid (Z,Z)- (15.25%), Ethanone-1-(2-hydroxy-4,6-dimethoxyphenyl)- (10.32%), cis-9-Hexadecenoic acid (6.21%), and Psilocin (11.75%). Among them, Ethanone-1-(2-hydroxy-4,6-dimethoxyphenyl)- and 9,12-Octadecadienoic acid (Z,Z)- have an obvious inhibitory effect on P. nicotianae. Additionally, changes in soil bacterial and fungal communities were observed. The relative abundance of some microbes, such as Pseudomonas, Azospirillum, Thermomonas, Glutamicibacter, Dyella, and Trichoderma, increased, which have many beneficial microbes in these genera, indicating that microbial community shift could be one of the important outcomes of the PSK fumigant effect. In conclusion, PSK could be a new bio-fumigation material against plant soilborne pathogens, which can function as both a fungicide and fertilizer.

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Resistance to Tobacco Black Shank in Nicotiana Species

Crop Science ◽

10.2135/cropsci2005.04-0027 ◽

2006 ◽

Vol 46 (2) ◽

pp. 554-560 ◽

Cited By ~ 8

Author(s):

B.‐C. Li ◽

W. T. Bass ◽

P. L. Cornelius

Keyword(s):

Black Shank ◽

Nicotiana Species ◽

Tobacco Black Shank

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Stem and Root Resistance to Tobacco Black Shank

Plant Disease ◽

10.1094/pdis.1999.83.8.777 ◽

1999 ◽

Vol 83 (8) ◽

pp. 777-780 ◽

Cited By ~ 24

Author(s):

A. S. Csinos

Keyword(s):

Coastal Plain ◽

Lesion Development ◽

Black Shank ◽

Root Decay ◽

Stem Resistance ◽

Race 1 ◽

Root Resistance ◽

Lower Stem ◽

Tobacco Black Shank

Stem lesion development in the absence of root decay in tobacco black shank caused by Phytophthora parasitica var. nicotianae has become common in the Coastal Plain tobacco growing area in Georgia. All aboveground symptoms of wilting, blackening of lower stem, and destruction of the pith can occur on tobacco without or with minor root decay. This type of black shank disease development occurred in 14 of 15 locations evaluated and accounted for about 30% of diseased plants. Cultivars with Florida 301—derived resistance had very low stem resistance to race 0 of the pathogen. However, root inoculations of these cultivars resulted in disease reactions typical of those expected in vivo in Georgia. Cultivars Coker 371-Gold and NC 71 and the breeding line 1071 demonstrated high resistance to inoculation with race 0 of P. parasitica var. nicotianae in both the stem and the roots, but they were susceptible when stem-inoculated with race 1 of the pathogen. Severity of root decay was isolate dependent.

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