## 3 Discussion  
The PUCV-VBL biocontrol was shown to produce a wide range of VOCs. Desirable for their volatile characteristics and diffusibility in the air [31; 32], VOCs are typically smaller than other BCAs secondary metabolites (up to C20) with low molecular mass (100-500 Daltons), high vapor pressure, low boiling point, and lipophilia [33]. These properties facilitate evaporation and diffusion through water- and gas-filled pores in soil and rhizosphere environments [34; 35]. The present work shows that PUCV-VBL biocontrol VOCs limited the mycelial growth of fungal pathogens in table grapes. For in vitro, _B. cinerea_ was most inhibited, at 86%. Next, VOCs emitted by component BCA _H. osmophila_ were shown to inhibit sporulation of _A. tubingensis_ and _P. expansum_ (Figure 1). This is similar to the results obtained by [PERSON] et al., [36] for _Bacillus licheniformis_ VOCs, who indicated that, among them, 3-methyl-1-butanol was most responsible for inhibiting mycelial growth and sporulation. Our results also showed 3-methyl-1-butanol as the predominant VOC molecule produced by _H. osmophila_. Interestingly, some _Bacillus_ spp.--including _B. subtilis_, _B. amyloliquefaciens_, and _B. cereus_--have been reported to produce 3-methyl-1-butanol and act as a robust antifungal compound [37]. SPME-GC-MS was used to identify VOCs from the PUCV-VBL biocontrol and its BCAs components, _G. cerinus_ and _H. osmophila_. VOCs were detected after 72 h of bioantagonist incubation. Principal component analysis (PCA) of SPME-GC-MS VOC data revealed heterogeneity in component contribution to VOCs (Figures 4 and 5). VOCs were similar between control and _G. cerinus_ and between _H. osmophila_ and the PUCV-VBL biocontrol. A Euclidean distance heat map based on the Ward algorithm for each treatment's replicas provides an intuitive visualization of all compounds (Figure 6). Both component BCAs produced the same compounds but with different relative peak areas, and they are present in different concentrations. There are two distinguishable VOC clusters: that of the PUCV  
Figure 7: Heat map with significant VOCs ANOVA (FDR = 0.05) FDR = False Discovery Rate. Control, grape without biocontrol, red; _G. cerinus_, grape with biocontrol _G. cerinus_, green; _H. osmophila_, grape with biocontrol _H. osmophila_ blue; PUCV-VBL, grape with PUCV-VBL consortium, light blue. Blue to reddish in the color code indicates down- to up-regulation of the compounds. VBL biocontrol and _H. osmophila_, in which VOC are overexpressed; and that of _G. cerinus_ and the control, with lesser concentrations. The VOCs significantly more present in _H. osmophila_ and the PUCV-VBL biocontrol were 1-butanol 3-methyl, propanoic acid ethyl ester, ethyl acetate, phenylethyl alcohol, isobutyl acetate, and hexanoic acid ethyl ester (Figure 7). It is almost certain that their antipathogenic effects are due to this overexpression. In total, the PUCV-VBL biocontrol VOCs were identified as ethyl acetate, propanoic acid ethyl ester, 1-butanol 3-methyl, 1-butanol, 2-methyl, propanoic acid 2-methyl ethyl ester, isobutyl acetate, butanoic acid ethyl ester, 2-butenoic acid ethyl ester (Z), butanoic acid 3-methyl ethyl ester, 1-butanol 3-methyl acetate, 1-butanol 2-methyl acetate, 1-butanol 2-methyl acetate, furan 2-pentyl, hexanoic acid ethyl ester, undecane, phenyl ethyl alcohol, octanoic acid ethyl ester, acetic acid 2-phenylethyl ester, tetradecane, and diethyl phthalate (Supplementary Material, Table S2). These compounds--mostly esters (65%), and to a lesser extent, alcohols (15%), alkanes (15%), and furan (5%)--have all been previously shown to have antifungal activity [28; 29; 30; 31; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51]. The low proportion of furan is concordant with other studies of, e.g., _Streptomyces albulus_ NJZJSA2 against _S. scleroorum_ and _Fusarium oxysporum_[43]. Mainly, [PERSON] et al., [52] reported that ethyl acetate might be involved in antimicrobial activity against _B. cinerea_[53].