Mechanism of a Volatile Organic Compound (6-Methyl-2-Heptanone) Emitted From Bacillus subtilis ZD01 Against Alternaria solani in Potato

Zhang, Dai; Qiang, Ran; Zhao, Jing; Zhang, Jinglin; Cheng, Jianing; Zhao, Dongmei; Fan, Yaning; Yang, Zhihui; Zhu, Jun‐Jie

doi:10.3389/fmicb.2021.808337

Cited by 15 publications

(10 citation statements)

References 47 publications

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“…The germination rate of the morphologically disrupted conidia was lowered to 75%, and these conidia formed irregular (shorter) germ tubes that were not able to penetrate and invade host epidermal cell junctions. This was also confirmed by the down-regulation of the expression of two genes: the slt2 gene, involved in mycelial growth, penetration, and pathogenicity [ 71 ], and the wetA gene, involved in sporulation and conidial wall formation [ 68 ]. B. safensis STJP VOCs (phenol, 2,4-bis (1,1-dimethylethyl)-, 3-hexadecanol, pyrrolo (1,2-a)pyrazine-1,4-dione, hexahydro-3-(2-methyl-propyl)-, 5,10-diethoxy-2,3,7,8-tetrahydro-1H,6H-dipyrrolo(1,2-a:10,20-d)pyrazine and hexadecanoic acid) have completely inhibited spore formation and conidia germination of Alternaria alternata [ 82 ].…”

Section: Mechanisms Of Action Of Antifungal Bacillus ...mentioning

confidence: 94%

“…Hyphae with wrinkled surface cells, surface swelling, and thinner cell walls were observed as a consequence of 6-methyl-2-heptanone (emitted by B. subtilis ZD01) treatment in Alternaria solani . As a result, the cytoplasm was shrunken, with an increased number of inclusions and larger liquid droplets, together with cytoplasmic content movement toward the ruptured cell walls or cytoplasmic membranes [ 68 ]. Hyphae of Alternaria alternata (tobacco brown spot) without any attached conidia appeared ruptured, shrunken, and twisted after being treated with 2-methylbutanoic acid and 3-methylbutanoic acid produced by B. siamensis LZ88 [ 69 ].…”

Section: Mechanisms Of Action Of Antifungal Bacillus ...mentioning

confidence: 99%

“…Damaged conidial internal structures with collapsed and shrunken small vesicles, extracellular secretions around the conidial cell-wall surface, and larger lipid droplets within the conidia were observed in Alternaria solani after treatment with 6-methyl-2-heptanone (EC 50 value of 10.88 μL) produced by B. subtilis ZD01 [ 68 ]. The germination rate of the morphologically disrupted conidia was lowered to 75%, and these conidia formed irregular (shorter) germ tubes that were not able to penetrate and invade host epidermal cell junctions.…”

Section: Mechanisms Of Action Of Antifungal Bacillus ...mentioning

confidence: 99%

“…The leading VOC with the strongest antifungal effect was 2,3-butanedione, which totally inhibited Alternaria iridiaustralis in wolfberry fruit at a concentration of 60 μL/L [ 73 ]. The VOCs produced by B. subtilis ZD01 significantly reduced lesion diameter in potato leaves, as well as the population density of Alternaria solani (early blight pathogen), with acetophenone, 2-nonanone, m -tolunitrile, 2-ethylhexanol, 2-heptanone, benzylacetone, 6-methyl-2-heptanone, benzothiazole, 5-methyl-2-hexanone, aniline, 4-methylanisole, benzoxazole, valerophenone, and 2,5-dimethylpyrazine as the major antifungal VOCs [ 68 ].…”

Section: Mechanisms Of Action Of Antifungal Bacillus ...mentioning

confidence: 99%

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Bacillus VOCs in the Context of Biological Control

2023

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A contemporary agricultural production system relying on heavy usage of agrochemicals represents a questionable outlook for sustainable food supply in the future. The visible negative environmental impacts and unforeseen consequences to human and animal health have been requiring a shift towards the novel eco-friendly alternatives for chemical pesticides for a while now. Microbial-based biocontrol agents have shown a promising potential for plant disease management. The bacteria of the genus Bacillus have been among the most exploited microbial active components due to several highly efficient mechanisms of action against plant pathogens, as well as a palette of additional plant-beneficial mechanisms, together with their suitable properties for microbial biopesticide formulations. Among other bioactive metabolites, volatile organic compounds (VOCs) have been investigated for their biocontrol applications, exhibiting the main advantage of long-distance effect without the necessity for direct contact with plants or pathogens. The aim of this study is to give an overview of the state-of-the-art in the field of Bacillus-based VOCs, especially in terms of their antibacterial, antifungal, and nematicidal action as the main segments determining their potential for biocontrol applications in sustainable agriculture.

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Section: Mechanisms Of Action Of Antifungal Bacillus ...mentioning

confidence: 94%

Section: Mechanisms Of Action Of Antifungal Bacillus ...mentioning

confidence: 99%

Section: Mechanisms Of Action Of Antifungal Bacillus ...mentioning

confidence: 99%

Section: Mechanisms Of Action Of Antifungal Bacillus ...mentioning

confidence: 99%

See 2 more Smart Citations

Bacillus VOCs in the Context of Biological Control

2023

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“…The 6-methyl-2-heptanone disrupts mycelial integrity, collapses conidial vesicles, and downregulates the conidial germination gene of pathogenic fungus [66]. The S-containing volatile compound benzothiazole inhibits cystospore germination and mycelial growth of Phythophthora parasitica var.…”

Section: Discussionmentioning

confidence: 99%

Suppressive Effects of Volatile Compounds from <em>Bacillus </em>spp. on <em>Magnaporthe oryzae Triticum</em> (MoT) Pathotype, Causal Agent of Wheat Blast

Surovy¹,

Rahman²,

Rostás³

et al. 2023

Preprint

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Magnaporthe oryzae Triticum (MoT) pathotype is the causal agent of wheat blast, which has caused significant economic losses and threatens wheat production in South America, Asia and Africa. Three bacterial strains from rice and wheat seeds (B. subtilis BTS-3, B. velezensis BTS-4, and B. velezensis BTLK6A) were used to explore the antifungal effects of volatile organic compounds (VOCs) of Bacillus spp. as a potential biocontrol mechanism against MoT. All bacterial treatments significantly inhibited both mycelial growth and sporulation of MoT in vitro. We found that this inhibition was caused by Bacillus VOCs in a dose-dependent manner. In addition, biocontrol assays using detached wheat leaves infected with MoT showed reduced leaf lesions and sporulation compared to the untreated control. VOCs from B. velezensis BTS-4 alone or a consortium (mixture of B. subtilis BTS-3, B. velezensis BTS-4, and B. velezensis BTLK6A) treatments consistently suppressed MoT in vitro and in vivo. Compared to the untreated control, VOCs from BTS-4 and Bacillus consortium reduced MoT lesions in vivo by 85% and 81.25%, respectively. A total of thirty-nine VOCs (from 9 different VOC groups) from 4 Bacillus treatments were identified by gas chromatography-mass spectrometry (GC-MS), of which 11 were produced in all Bacillus treatments. Alcohols, fatty acids, ketones, aldehydes, and S-containing compounds were detected in all four bacterial treatments. In vitro assays using pure VOCs revealed that hexanoic acid, 2-methylbutanoic acid, and phenylethyl alcohol are potential VOCs emitted by Bacillus spp. that are suppressive for MoT. The minimum inhibitory concentrations for MoT sporulation were 250 mM for phenylethyl alcohol and 500 mM for 2-methylbutanoic acid and hexanoic acid. Therefore, our results indicate that VOCs from Bacillus spp. are effective compounds to suppress the growth and sporulation of MoT. Understanding the MoT sporulation reduction mechanisms by Bacillus VOCs may provide novel options to manage the further spread of wheat blast by spores.

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