## 1 Introduction  
The aroma of grapes and wine is an important quality indicator that influences consumer preferences. It is influenced by various factors, including grape variety, vintage, climate, cultivation practices, and ripeness [1, 2]. Grape aroma compounds primarily originate from the metabolic conversion of amino acids, sugars, and fatty acids via the amino acid, isoprene, and fatty acid pathways. Among them, C6 compounds, such as C6 aldehydes, C6 alcohols, and C6 esters, are derived from the fatty acid pathway. These compounds are produced from linolenic and linoleic acids, which are catalyzed by hydroperoxide lyase (HPL), lipoxygenase (LOX), alcohol acetyltransferase (AAT), and alcohol dehydrogenase (ADH) [1]. C6 compounds contribute to the aromatic profile of grape berries and wines, imparting \"green leafy\", \"grassy\", or \"fresh plant\" odors. Additionally, these compounds serve as precursors for hexjet acetate in wines and the distinctive aroma compound 3-mercapto-1-hexanol (3 MH) found in New Zealand's Sauvignon Blanc white wine [3, 4]. Several factors have been found to influence the production and accumulation of C6 compounds in grape cultivation. These factors include the viticultural environment climate [5, 6], grape variety [7, 8], maturity stages [8, 9], cluster thinning [10, 11], light condition of the berry microclimate [11], training system [12, 13], rainfall [14], and exogenous spraying [15, 16]. Moreover, a recent study was conducted to examine the influence of the grape ripening stage and phytosanitary state on C6 compounds, revealing significant effects [17]. Among these factors, exogenous spraying of elicitor is considered a green, environmentally friendly, highly efficient, stabilized, and non-residual cultivation management strategy that is of great interest in grape cultivation. Benzothiadiazole (BTH) is a commercial chemical elicitor that activates systemic acquired resistance (SAR) in plants by mimicking the endogenous signaling molecule salicylic acid (SA). In grapes, BTH induces the plant's natural immune response; triggers local or systemic defense responses; and contributes to the increase in cell wall proteins, phenolics, and cellulose composition [18; 19], resulting in an enhanced color intensity [20; 21]. Moreover, it has been observed that BTH exhibits a diminishing effect on the levels of essential metabolites, particularly soluble sugars and amino acids, in grapes [22; 23]. Additionally, it has been found to modify the composition of soluble sugars [23]. Soluble sugars have a dual role in fruits. They not only affect the organoleptic quality of fruits but also serve as important signaling molecules. In grapes, these sugars play a crucial role in influencing the production of secondary metabolites by participating in defense responses and regulating the transcription of metabolic genes [23; 24]. In addition, the effect of BTH on grapes' soluble sugars and total acids alters grapes' ripening time [19]. BTH affects the grape anthocyanin composition, grape skin tannin, and flavonoid content [25; 26], as well as the concentration of terpenids and norisoprenoids in grapes [22]. Previous research has mostly examined the impact of BTH application on the grape cell wall composition [18; 19], phenolic compounds [15; 21; 27], color [19; 28], and hydrogen peroxide and reactive oxygen species (ROS) metabolism [18; 29; 30]. However, a limited number of studies have examined the impact of BTH on the composition of grape aroma compounds [31]. Our previous study found that BTH sprayed on Cabernet Gernischt grapes at the swelling stage resulted in higher concentrations of aroma compounds than BTH-treated grapes at the fruit-set and verasion stages [22]. Therefore, in this study, to further clarify the effects of BTH treatment on the physicochemical parameters and accumulation of C6 compounds in Cabernet Gernischt grapes, an experiment was conducted by spraying 0.37 mM BTH on Cabernet Gernischt grapes at the pre-swelling stage.