iTRAQ-Based Proteomic Analysis Reveals the Role of the Biological Control Agent, Sinorhizobium fredii Strain Sneb183, in Enhancing Soybean Resistance Against the Soybean Cyst Nematode

Abstract

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, poses a serious threat to soybean production worldwide. Biological control agents have become eco-friendly candidates to control pathogens. Our previous study indicated that the biocontrol agent, Sinorhizobium fredii strain Sneb183, may induce soybean resistance to SCN. To study the mechanisms underlying induced disease resistance in the plant by Sneb183, an iTRAQ (isobaric tag for relative and absolute quantitation)-based proteomics approach was used to identify proteomic changes in SCN-infected soybean roots derived from seeds coated with the Sneb183 fermentation broth or water. Among a total of 456 identified differentially expressed proteins, 212 and 244 proteins were upregulated and downregulated, respectively, in Sneb183 treated samples in comparison to control samples. Some identified differentially expressed proteins are likely to be involved in the biosynthesis of phenylpropanoid, flavone, flavanol, and isoflavonoid and have a role in disease resistance and adaptation to environmental stresses. We used quantitative real-time PCR (qRT-PCR) to analyze key genes, including GmPAL (phenylalanine ammonia-lyase), GmCHR (chalcone reductase), GmCHS (chalcone synthase), and GmIFS (isoflavone synthase), that are involved in isoflavonoid biosynthesis in Sneb183-treated and control samples. The results showed that these targeted genes have higher expression levels in Sneb183-treated than in control samples. High performance liquid chromatography (HPLC) analysis further showed that the contents of daidzein in Sneb183-treated samples were 7.24 times higher than those in control samples. These results suggested that the Sinorhizobium fredii strain Sneb183 may have a role in inducing isoflavonoid biosynthesis, thereby resulting in enhanced resistance to SCN infection in soybean.

Exogenously applied melatonin alleviates the damage in cucumber plants caused by Aphis goosypii through altering the insect behavior and inducing host plant resistance

“…When pathogens attacked plants, C4H has been confirmed to participate in the accumulation of flavonoids and isoflavones, and to enhance cell wall lignification and soybean resistance. 77 The stability of flavonols can be improved by catalytic glycosylation of flavonols through UDP-sugar-dependent glycosyltransferases (UGTs). 73,78 Furthermore, PPO dominates the conversions of flavonols glycosides and reduces their content.…”

Biocontrol of Three Severe Diseases in Soybean

“…Sinorhizobium fredii is another important biocontrol agent against H. glycines. Suspension of isolate Sneb183 was inoculated to soybean plants and reduced the numbers of juveniles and cysts and inhibited the egg hatching of H. glycines [117,118]. Another isolate, L396, also inhibited egg hatching and improved the mortality rate of H. glycines [119].…”

Evaluation of Scopoletin from Penicillium janthinellum Snef1650 for the Control of Heterodera glycines in Soybean

“…Soybean seeds of susceptible cultivars treated with the Snef1650 fermentation liquid demonstrated increased SCN tolerance and a boost in growth and yield. Studies have demonstrated that microorganismtreated seeds produce nematicides during root development and resist infection due to different parasitic nematodes through systemic or local induction of endogenous hormones and plant defense-related proteins in the plant immune system [32][33][34][35][36][37].…”