Suppressive efficacy of volatile compounds produced byBacillus mycoideson damping-off pathogens of cabbage seedlings

Abstract

Rhizoctonia solani Kühn and Pythium aphanidermatum Edson cause cabbage seedling damping-off, resulting in severe yield losses. The current study demonstrates the production of toxic volatile organic compounds (VOCs) by two strains of Bacillus mycoides and the evaluation of a potential use of B. mycoides as a biocontrol agent to control cabbage damping-off. Two VOCs, dimethyl disulphide and ammonia, were found to reduce radial growth, cause hyphal deformation and result in organelle degeneration in both R. solani and P. aphanidermatum. Pathogen hyphae, after being exposed to VOCs, showed poor rigidity, shrinkage, curling and swelling. The amount of VOCs produced by B. mycoides and the antagonistic activity against plant pathogens varied, depending on the type of medium used to culture bacteria. Application of B. mycoides cell suspensions to cultivation medium promotes growth of five different plant species tested. Experiments conducted in greenhouses revealed that B. mycoides did not reduce damping-off incidence caused by R. solani. However, B. mycoides reduced damping-off incidence induced by P. aphanidermatum by as much as 45% on cabbage seedlings. The results provide valuable information on the feasibility of utilizing B. mycoides as a biocontrol agent in controlling cabbage damping-off.

Volatile Compounds From Bacillus, Serratia, and Pseudomonas Promote Growth and Alter the Transcriptional Landscape of Solanum tuberosum in a Passively Ventilated Growth System

“…The largest increases in dry biomass were observed after exposure to BVCs from LAM7 and BRP14, 2.69-and 2.57-fold greater than that of the axenic media control respectively, suggesting that the volatile blends from these isolates cultured in MR-VP are strong growth-promoters. Our analysis identified 2,3-butanediol and 3-hydroxy-2-butanone within the headspace of B. mycoides (LAM7), interestingly these were not detected in the headspace of B. mycoides strains (CHT2401) and (CHT2402) in a previous study (Huang et al, 2018). This may indicate that bacterial strains within a particular species may harbor the ability to employ strain-specific BVCs for exploitation of particular ecological niches under the correct environmental conditions as described for Bacillus subtilis (Kai, 2020), additionally, interlaboratory variation in volatile profiles cannot be discounted (Clark et al, 2021).…”

Bacterial volatile organic compounds induce adverse ultrastructural changes and DNA damage to the sugarcane pathogenic fungus Thielaviopsis ethacetica

“…Regarding the VOCs that were produced in specific culture media, LB was prominent, with 16 compounds produced exclusively in that medium, followed by DYGS with nine and ANGLE with only one compound, reinforcing that the culture medium is critical for the composition of the volatilome of antagonists, as shown in the media assay results (Fig. 2B) and as reported previously (Gotor‐Vila et al ., 2017; Huang et al ., 2018). It is worth to mention that the production of these compounds can be different during the interaction with other microorganisms (Sánchez‐Fernández et al ., 2016; Ebadzadsahrai et al ., 2020).…”

The power of the smallest: The inhibitory activity of microbial volatile organic compounds against phytopathogens

“…Guo et al, 2019b) or even the same species (Macías-Rubalcava et al, 2018;Guevara-Avendaño et al, 2019), but also some uniqueness by each one. Those conditions can be media composition (Fiddaman and Rossall, 1994;Bruce et al, 2004;Raza et al, 2015;Asari et al, 2016;Huang et al, 2018;Morita et al, 2019), media consistency (Dickschat et al, 2005;Qadri et al, 2015), period of incubation/growth stage (Weise et al, 2012;Giorgio et al, 2015;Sánchez-Fernández et al, 2016;Macías-Rubalcava et al, 2018;Misztal et al, 2018;Yang et al, 2019), humidity/water content (Jeleń, 2002;Misztal et al, 2018), temperature (Jeleń, 2002), oxygen and carbon dioxide levels (Zhang et al, 2013a), and interactions with other organisms (Sánchez-Fernández et al, 2016;Delgado et al, 2021). Such dynamicity and diversity of microbial VOCs can influence complex environmental trophic interactions (Fiedler et al, 2001;Bitas et al, 2013).…”

“…It is well known that microbial volatilomes also vary according to the producing microorganism, showing some similarities among microbes belonging to the same genus ( Choudoir et al, 2019 ; Guo et al, 2019b ) or even the same species ( Macías-Rubalcava et al, 2018 ; Guevara-Avendaño et al, 2019 ), but also some uniqueness by each one. Those conditions can be media composition ( Fiddaman and Rossall, 1994 ; Bruce et al, 2004 ; Raza et al, 2015 ; Asari et al, 2016 ; Huang et al, 2018 ; Morita et al, 2019 ), media consistency ( Dickschat et al, 2005 ; Qadri et al, 2015 ), period of incubation/growth stage ( Weise et al, 2012 ; Giorgio et al, 2015 ; Sánchez-Fernández et al, 2016 ; Macías-Rubalcava et al, 2018 ; Misztal et al, 2018 ; Yang et al, 2019 ), humidity/water content ( Jeleń, 2002 ; Misztal et al, 2018 ), temperature ( Jeleń, 2002 ), oxygen and carbon dioxide levels ( Zhang et al, 2013a ), and interactions with other organisms ( Sánchez-Fernández et al, 2016 ; Delgado et al, 2021 ).…”