Non-targeted screening and trimethylamine determination in Tilletia foetida-infected wheat using HS-SPME-GC-MS

Abstract

Common bunt disease of wheat in China is caused mainly by Tilletia foetida. However, reliable approaches for determining disease-associated biochemical markers are rarely reported. Here, a headspace-solid-phase microextraction coupled with headspace GC-tandem mass spectrometry (HS-SPME-GC-MS) was used to screen volatile substances in infected wheat, and an optimal chemical marker was selected to establish analytical methods for disease determination. Non-targeted screening of 13 volatile compounds unique to diseased wheat allowed a metabolite with rotten fish-like smell, trimethylamine (TMA), to be selected as the inspection marker. Subsequently, two analytical methodologies, HS-SPME-GC-MS and headspace gas chromatography with flame ionization detection (HS-GC-FID), were established to determinate the TMA content in wheat. The linear relationship, recovery and reproducibility of the methods were validated. The limit of detection (LOD) was 0.02 µg/kg for the former method, 5000-fold lower than that for the latter. When analysing samples, HS-SPME-GC-MS showed excellent sensitivity and allowed for the determination of 0.05% infected kernels among whole wheat grains. Therefore, TMA determination using HS-SPME-GC-MS is an effective alternative method to detect wheat common bunt disease occurring at extremely low infection rate.

Graphical abstract

Keywords:

• Wheat
• Tilletia foetida
• volatile compounds
• solid-phase micro-extraction (SPME)
• gas chromatograph-tandem mass spectrometry (GC-MS)
• trimethylamine (TMA)

Acknowledgements

We thank Liwen Bianji (Edanz) (https://www.liwenbianji.cn) for editing the language of drafts of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Science and Technology Project of Jiangsu Market Supervision Administration [No. KJ21125051, KJ2022069, KJ2022070]; Science and Technology Project of Jiangsu Science and Technology Department [No. BE2020627]; National Key Research and Development Program of China [No. 2021YFF0600805]; Science and Technology Program of State Administration for Market Regulation [No. 2022MK159, 2022MK160].