## 5 Conclusions  
Based on the data shown in this study, the following model was proposed linking the release of VOCs by BF06 to activation of Fe and Se uptake in plants (Figure 12). BF06 VOCs triggered the accumulation of NO in roots, thereby stimulating Fe acquisition systems. Moreover, BF06 VOCs exposure also induced a great increase of Se accumulation in plants via the activation of some sulfate transporters. This research provides evidence that the production of VOCs by BF06 can regulate plant uptake of Fe and increase its bioavailability under alkaline conditions, and also demonstrates its potential roles in promoting Se assimilation in plants.  
Figure 12: A proposed model of BF06 VOCs-induced Fe and Se absorption in plants. The release of VOCs by BF06 can induce root NO accumulation, thereby increasing the availability of cell wall Fe and activating FIT1-mediated Fe acquisition. Moreover, BF06 VOCs has been shown to improve plant uptake of Se through the regulation of some important sulfate transporters.  
**Supplementary Materials:** The following are available online at [[http://www.mdpi.com/2076-3417/7/1/85/s1](http://www.mdpi.com/2076-3417/7/1/85/s1)]([http://www.mdpi.com/2076-3417/7/1/85/s1](http://www.mdpi.com/2076-3417/7/1/85/s1)), Table S1: Primers used in this study; Table S2: Volatile profile of _Bacillus amyloligaciens_ BP60, using headspace solid-phase micro extraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). Different letters represent a significant difference between the control and VOCs-exposed plants at \(p<0.05\); Table S3: Uregulated and downregulated genes (more than 2-fold) differentially expressed in the VOCs-exposed plants; Table S4: Uregulated or downregulated differentially expressed genes (DEGs) including some amino acid transport-, Fe acquisition-, and sulfate transport-related genes in the VOCs-exposed plants; Figure S1: List of the top 10 significant GO terms in biological process (BP) domain for downregulated differentially expressed genes (DEGs) in the VOCs-exposed plants based on GO classifications. The \(p\) value indicates a significant difference between the control and VOCs-exposed plants.  
**Acknowledgments:** This work was supported by the National Natural Science Foundation of China (31600210), the Research Foundation of the Ministry of Agriculture (BOFC2015 KB02), the National Sparking Plan Project (2015 GA710013, 2015 GA710014), the Key Research Project of the Anhui Science and Technology Committee (1301032151, 15 CZZ03102), the Natural Science Foundation of Anhui Province (1508085 QD74, 1608085 MC59), the Public Technological Application Project of the Anhui Science and Technology Committee (1604f0704045), and the Research Foundation of Anhui Science and Technology University (ZRC2014403).  
**Author Contributions:** [PERSON] and [PERSON] conceived and designed the experiment; [PERSON] and [PERSON] performed the experiment; [PERSON], [PERSON], [PERSON], and [PERSON] analyzed the data; [PERSON] wrote the paper.  
**Conflicts of Interest:** The authors declare no conflict of interest. The funding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.