Abstract
A strain of Rhodococcus ruber was isolated from the rhizosphere of Spartina alterniflora. The VOCs released by this strain effectively promote the growth of Arabidopsis thaliana and inhibit several plant pathogenic fungi, including Bipolaris sorokiniana, Cryphonectria parasitica, Fusarium oxysporum, Fusarium pseudograminearum, and Plectosphaerella cucumerina. SPME/GC-MS analysis revealed that the strain produces dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS), with DMDS being the predominant component of the volatile organic compounds (VOCs). It was observed that the growth of A. thaliana was enhanced under fumigation with DMDS and DMTS. Furthermore, these compounds effectively inhibited the aforementioned plant pathogenic fungi, with DMTS demonstrating a lethal effect on plant pathogenic fungi. Previous studies have confirmed that DMDS and DMTS promote the growth of A. thaliana. In this study, we found that DMTS could significantly enhance plant growth and inhibit plant pathogenic fungi even at low dosages. Transcriptome analysis indicated that the growth-related genes of A. thaliana were significantly upregulated in response to treatment with VOCs from R. ruber. Additionally, VOCs induced changes in multiple plant defense response genes and promoted the C4 pathway.