Wheat aroma biomarkers induced by saline-alkali soil: based on HS-SPME-GC-MS and molecular docking

The precise volatile compounds accountable for the characteristic scent of the wheat aroma were presently unidentified. Given the prominent manifestation of "wheat aroma" in wheat cultivated in saline-alkali (SA) soil, five wheat varieties planted in saline-alkali soil and control soil (low saline-alkali soil) to create "rich-aroma" and "bland-aroma" samples, respectively.

The volatile profiles of these two groups of samples were analyzed using headspace solid-phase microextraction coupled with gas chromatographyed with gas chromathes-SPME-GC-MS), and differential characteristic volatile compounds between "rich-aroma" and "bland-aroma" samples were identified by combining paired t-tests, relative odor activity values (ROAVs), and molecular docking analysis.

A total of 75 volatile compounds were identified using HS-SPME-GC-MS. Paired t-test result revealed that a significant increase (p < 0.05) in the peak areas and relative contents of limonene (>109.74% increase), β-pinene (> 474.09% increase) contrasted with reduced butanoic acid (>38.71% reduction) and (E,E)-3,5-octadien-2-one (>16.05% reduction) in saline-alkali soil-cultivated wheats. Molecular docking demonstrated high binding energies (<-4.25 kcal/mol) of limonene, β-pinene, and (E,E)-3,5-octadien-2-one to olfactory receptors, corroborated by relative odor activity values (ROAVs. > 1).

Limonene, β-pinene and (E,E)-3,5-octadien-2-one are identified as possible saline-alkali soil-induced wheat aroma biomarkers, and offer theoretical insights for verificating wheat aroma. Identifying potential characteristic biomarkers in wheat under saline-alkali stress provides important theoretical insights for improving the flavor characteristics of wheat.