Volatile Organic Compound (VOC) Profiles of Different Trichoderma Species and Their Potential Application

Abstract

Fungi emit a broad spectrum of volatile organic compounds (VOCs), sometimes producing species-specific volatile profiles. Volatilomes have received over the last decade increasing attention in ecological, environmental and agricultural studies due to their potential to be used in the biocontrol of plant pathogens and pests and as plant growth-promoting factors. In the present study, we characterised and compared the volatilomes from four different Trichoderma species: T. asperellum B6; T. atroviride P1; T. afroharzianum T22; and T. longibrachiatum MK1. VOCs were collected from each strain grown both on PDA and in soil and analysed using proton transfer reaction quadrupole interface time-of-flight mass spectrometry (PTR-Qi-TOF-MS). Analysis of the detected volatiles highlighted a clear separation of the volatilomes of all the four species grown on PDA whereas the volatilomes of the soil-grown fungi could be only partially separated. Moreover, a limited number of species-specific peaks were found and putatively identified. In particular, each of the four Trichoderma species over-emitted somevolatiles involved in resistance induction, promotion of plant seed germination and seedling development and antimicrobial activity, as 2-pentyl-furan, 6PP, acetophenone and p-cymene by T. asperellum B6, T. atroviride P1, T. afroharzianum T22 and T. longibrachiatum MK1, respectively. Their potential role in interspecific interactions from the perspective of biological control is briefly discussed.

Trichoderma harzianum Volatile Organic Compounds Regulated by the THCTF1 Transcription Factor Are Involved in Antifungal Activity and Beneficial Plant Responses

“…As might be expected, the PTR-Qi-TOF-MS analysis showed that many VOCs were present in similar abundance in samples from the three T. harzianum strains, not showing significant differences at the two time points considered, such as those putatively identified as decanal, acetaldehyde, 2,4-dimethylfuran, furan, formaldehyde, 1,2,4-trimethylbenzene, 6,10-dimethyl-5,9-undecadien-2-one (geranylacetone), p -cymene, methanethiol, 3-methylacetophenone, 2-methoxy-4-methylphenol (=creosol), sesquiterpenes, ethanol, methanol, hexenal isomeres and cedrol, molecules all known to be normally emitted by different microbes, including Trichoderma spp. [ 18 , 38 , 50 , 72 ]. However, no significant differences in the production levels of 6-PP and its derivatives were detected among the three strains of T. harzianum under the experimental condition of the present study.…”

“…To perform VOCs analysis of Trichoderma strains, a 5 mm diameter agar plug with the fungus was placed at the center of a 1 L Erlenmeyer conical glass flask equipped with a GL45 3-valve screw cap, containing 100 mL of PDA. VOCs protonation and measurements of headspace VOC profiles accumulated in the flasks were carried out as previously described [ 38 ]. Four different biological replicates for each sample were analyzed and the measurements were taken at five (half of the agar surface was colonized by the mycelium) and nine (all the agar surface was colonized by the mycelium) days post inoculation.…”

“…Data acquisition and peak quantification were expressed as normalized parts per billion by volume (ppbv). The calibration of the PTR spectra and the elimination of peaks associated with the PTR-MS ion source were performed as previously described [ 38 ]. The m / z signals were background-corrected by subtracting the signal obtained from the glass flasks containing only PDA.…”

“…Several investigations have demonstrated the antimicrobial properties of Trichoderma VOCs [ 23 , 24 , 25 , 26 , 27 , 28 ] as well as their role in the induction of defenses and/or growth promotion in plants [ 19 , 22 , 29 , 30 , 31 , 32 , 33 , 34 ]. Production of VOCs in Trichoderma is directly dependent not only on the species, but also on the strain, and it is also affected by growth conditions, developmental stage and the abiotic or biotic cues received from the environment [ 21 , 35 , 36 , 37 , 38 ]. Moreover, depending on conditions, VOCs from the same Trichoderma isolate can either stimulate plant growth or induce toxicity [ 32 ].…”

Plant hormones mediate the interaction between oak acorn germination and rodent hoarding behaviour

“…One compound (1‐Nonen‐4‐ol) has been reported to be associated with ozone release (Li et al ., 2018). Notably, 2‐pentyl‐Furan has been reported to change significantly before and after seed germination in some species of Vicia sativa , and the production of this substance by Xylemiaceae promotes spore germination (Gualtieri et al ., 2022; Riley et al ., 2022). Unfortunately, these compounds are currently unavailable, limiting our ability to verify their ecological effect.…”