Trichoderma pubescens Elicit Induced Systemic Resistance in Tomato Challenged by Rhizoctonia solani.

Rhizoctonia solani causes severe diseases in many plant species, particularly root rot in tomato plants. For the first time, Trichoderma pubescens effectively controls R. solani in vitro and in vivo. R. solani strain R11 was identified using the ITS region (OP456527); meanwhile, T. pubescens strain Tp21 was characterized by the ITS region (OP456528) and two genes (tef-1 and rpb2). The antagonistic dual culture method revealed that T. pubescens had a high activity of 76.93% in vitro. A substantial increase in root length, plant height, shoot fresh and dry, and root fresh and dry weight was indicated after applying T. pubescens to tomato plants in vivo. Additionally, it significantly increased the chlorophyll content and total phenolic compounds. The treatment with T. pubescens exhibited a low disease index (DI, 16.00%) without significant differences with Uniform® fungicide at a concentration of 1 ppm (14.67%), while the R. solani-infected plants showed a DI of 78.67%. At 15 days after inoculation, promising increases in the relative expression levels of three defense-related genes (PAL, CHS, and HQT) were observed in all T. pubescens treated plants compared with the non-treated plants. Plants treated with T. pubescens alone showed the highest expression value, with relative transcriptional levels of PAL, CHS, and HQT that were 2.72-, 4.44-, and 3.72-fold higher in comparison with control plants, respectively. The two treatments of T. pubescens exhibited increasing antioxidant enzyme production (POX, SOD, PPO, and CAT), while high MDA and H2O2 levels were observed in the infected plants. The HPLC results of the leaf extract showed a fluctuation in polyphenolic compound content. T. pubescens application alone or for treating plant pathogen infection showed elevated phenolic acids such as chlorogenic and coumaric acids. Therefore, the ability of T. pubescens to inhibit the growth of R. solani, enhance the development of tomato plants, and induce systemic resistance supports the application of T. pubescens as a potential bioagent for managing root rot disease and productivity increase of crops.

Plantago lagopus extract as a green fungicide induces systemic resistance against Rhizoctonia root rot disease in tomato plants.

Extensive use of chemical control agents and fungicides typically leads to numerous risks to human health and the environment. Using plant extracts as natural substances represents a dual key for the environment and sustainable food production, as it reduces the input of synthetic pesticides into the environment and/or controls plant pathogens. For the first time, a Plantago lagopus ethanolic extract has been characterized and evaluated for its protective and curative effects against Rhizoctonia solani in tomato plants. The results showed that P. lagopus extract (10 µg/ml) completely inhibited R. solani mycelial growth in vitro. At 20 days of post fungal inoculation, the results demonstrated that using P. lagopus extract (100 µg/ml) in vivo enhanced tomato plant growth by significantly increasing shoot and root parameters in protective and curative treatments. Furthermore, the protective and curative treatments significantly reduced the disease index by 18.66 and 38.66%, respectively. Induction of systemic resistance with upregulation of PR-1 and PR-2 and a significant increase in the transcriptional levels of PR-3 and CHS in all P. lagopus extract-treated tomato plants were reported compared to untreated plants. HPLC analysis showed that the most common polyphenolic components detected in P. lagopus extract were rutin (74206.3 mg/kg), naringenin (2388.74 mg/kg), quercetin (1249.13 mg/kg), and p-hydroxybenzoic acid (1035.87 mg/kg). In addition, the ellagic acid (798.47 mg/kg), vanillic acid (752.55 mg/kg), catechol (648.89 mg/kg), cinnamic acid (332.51 mg/kg), ferulic acid (296.32 mg/kg), benzoic acid (295.95 mg/kg), and chlorogenic acid (116.63 mg/kg) were also reported. Our study is the first to show that P. lagopus extract can help plants fight off R. solani fungal infection. Furthermore, the findings imply that using the P. lagopus extract as a natural biocontrol agent could be a sustainable strategy to manage plant fungal diseases.

Biochemical Characterization, Antifungal Activity, and Relative Gene Expression of Two Mentha Essential Oils Controlling Fusarium oxysporum, the Causal Agent of Lycopersicon esculentum Root Rot.

Tomato (Lycopersicon esculentum Mill.) is important food in daily human diets. Root rot disease by Fusarium oxysporum caused huge losses in tomato quality and yield annually. The extensive use of synthetic and chemical fungicides has environmental risks and health problems. Recent studies have pointed out the use of medicinal plant essential oils (EOs) and extracts for controlling fungal diseases. In the current research, Mentha spicata and Mentha longifolia EOs were used in different concentrations to control F. oxysporum. Many active compounds are present in these two EOs such as: thymol, adapic acid, menthol and menthyl acetate. These compounds possess antifungal effect through malformation and degradation of the fungal cell wall. The relative expression levels of distinctly upregulated defense-related WRKY genes (WRKY1, WRKY4, WRKY33 and WRKY53) in seedling root were evaluated as a plant-specific transcription factor (TF) group in different response pathways of abiotic stress. Results showed significant expression levels of WRKY, WRKY53, WRKY33, WRKY1 and WRKY4 genes. An upregulation was observed in defense-related genes such as chitinase and defensin in roots by application EOs under pathogen condition. In conclusion, M. spicata and M. longifolia EOs can be used effectively to control this plant pathogen as sustainable and eco-friendly botanical fungicides.