Biological control of bacterial wilt in tomato through the metabolites produced by the biocontrol fungus, Trichoderma harzianum

Abstract

Background Ralstonia solanacearum causes bacterial wilt disease in tomato and other crops resulting in huge economic losses worldwide. Several measures have been explored for the control of R. solanacearum, but the desired control level of the disease through sustainable and ecofriendly way is still awaited. Main body In this study, fungal metabolites produced by Trichoderma harzianum were investigated in the form of crude extract for the management of R. solanacearum both in vitro and in planta in tomato plants. In in vitro investigation, fungal metabolites were checked for their antibacterial potential at different concentrations (30, 60, 90, 120, 150, and 180 mg ml−1) and bacterial cell morphology was observed under scanning electron microscopy (SEM). In a greenhouse experiment, different application times (0, 3, and 6 days before transplantation DBT) and doses (0, 3, 6, and 9%) of the fungal metabolites were tested for their effects on soil bacterial population, disease severity and plant growth of tomato plants. The in vitro evaluation showed a strong antibacterial activity of fungal metabolites in concentration dependent manner. The highest concentration 180 mg ml−1 produced maximum inhibition zone (20.2 mm) having non-significant difference with the inhibition zone (20.5 mm) produced by the standard antibiotic streptomycin. The SEM analysis revealed severe morphological destructions of bacterial cells. In case of greenhouse experiment, the highest decrease in soil bacterial population, lowest disease severity, and maximum increase in plant growth parameters were obtained by highest dose (9%) and longest application time (6 DBT). Conclusion The fungal metabolites produced by T. harzianum could be used as low-cost, environment-friendly, and sustainable management strategy for the control of R. solanacearum in tomato plants.

Effects of Abiotic Stress on Soil Microbiome

“…Other than that, fungi also are known as biological controllers which helps to control diseases caused by phytopathogenic fungi. For example, Aureobasidium pullulans is a yeast-like fungus that has potential to control disease caused by fungal pathogens in apple, strawberry and grape, Rhizofagus irregularis and Talaromyces assiutensis can be used to control disease in olives, and Trichoderma harzianum is a well-studied fungus that can be used to control many diseases including Fusarium wilt, root rot and bacterial wilt [43][44][45]. Fungal communities in soil are important in P solubilization and N 2 uptake for host [46,47].…”

Network Analysis Reveals Different Cellulose Degradation Strategies across Trichoderma harzianum Strains Associated with XYR1 and CRE1

“…Although T. harzianum strains have shown high cellulolytic activity (Horta et al, 2018;Li et al, 2020b), most studies investigating this species have focused on biological control (Maruyama et al, 2020;Yan and Khan, 2021). Thus, the regulatory mechanisms underlying hydrolytic enzyme production by these fungi are still poorly explored at the transcriptional level (Delabona et al, 2017(Delabona et al, , 2020(Delabona et al, , 2021.…”

Plant Triterpenoids Regulate Endophyte Community to Promote Medicinal Plant Schisandra sphenanthera Growth and Metabolites Accumulation

“…Some endophytic Bacillus sp., Xanthomonas sp., Pantoea sp., Trichoderma sp., and Fusarium sp. were treated as an effective bio-control agent against phytopathogenic fungi [20,[54][55][56][62][63][64][65][66][67][68]. As a consortium, the microbes promoted by triterpenoids are beneficial to the plant, as they can unite the inter-kingdom and the outer-kingdom microbial consortia, and also promote plant growth.…”