Use of Trichoderma culture filtrates as a sustainable approach to mitigate early blight disease of tomato and their influence on plant biomarkers and antioxidants production

Abstract

IntroductionAlternaria solani is a challenging pathogen in the tomato crop globally. Chemical control is a rapid approach, but emerging fungicide resistance has become a severe threat. The present study investigates the use of culture filtrates (CFs) of three species of Trichoderma spp. to control this disease.MethodsHighly virulent A. solani strain and three Trichoderma fungal strains viz., T. harzianum (Accession No: MW590687), T. atroviride (Accession No: MW590689) and T. longibrachiatum (Accession No: MW590688) previously isolated by authors were used in this study. The efficacy of culture filtrates (CFs) to mitigate early blight disease were tested under greenhouse and field conditions, experiments were conducted in different seasons of 2020 using a tomato variety “doucen”.Results and discussionThe CFs of T. harzianum, T. longibrachiatum, and T. atroviride significantly inhibited the in vitro mycelial growth of A. solani (62.5%, 48.73%, and 57.82%, respectively, followed by control 100%). In the GC–MS analysis of Trichoderma CF volatile compounds viz., harzianic acid (61.86%) in T. harzianum, linoleic acid (70.02%) in T. atroviride, and hydroxymethylfurfural (68.08%) in the CFs of T. longibrachiatum, were abundantly present. Foliar application of CFs in the greenhouse considerably reduced the disease severity (%) in all treatments, viz., T. harzianum (18.03%), T. longibrachiatum (31.91%), and T. atroviride (23.33%), followed by infected control (86.91%), and positively affected the plant biomarkers. In the greenhouse, the plants treated with CFs demonstrated higher flavonoids after 6 days of inoculation, whereas phenolic compounds increased after 2 days. The CF-treated plants demonstrated higher antioxidant enzymes, i.e., phenylalanine ammonia-lyase (PAL) and peroxidase (POD), after 4 days, whereas polyphenol oxidase (PPO) was higher after 6 days of inoculation, followed by healthy and infected controls. In open field conditions, disease severity in CF-treated plants was reduced in both seasons as compared to naturally infected plants, whereas CF-treated plants exhibited a higher fruit yield than controls. The present results conclude that CFs can be a potential biocontrol candidate and a promising alternative to the early blight pathogen for sustainable production.

Impact of Seed Inoculation with Trichoderma afroharzianum Strains on Plant Growth, Root Morphology, and Leaf Phenolic Content in Hemp (Cannabis sativa L.) at Early Growth Stages

“…Singh and coworkers [58] reported that the protection of sunflower plants afforded by T. harzianum against Rhizoctonia solani was associated with the accumulation of antioxidants including phenolic compounds that played a crucial role in counteracting the oxidative stress produced by the pathogen attack. Similarly, the accumulation of phenolic compounds and other antioxidants induced by treatment with T. harzianum reduced the severity of early blight disease in tomato plants [15] and alleviated the oxidative stress caused by the Fusarium crown rot disease in durum wheat [33].…”

“…It is generally assumed that Trichoderma spp. may induce the plant to shift from primary to secondary metabolism with the consequent accumulation of secondary metabolites of phenolic nature [13][14][15]. The buildup of these compounds may serve as an antioxidant defense mechanism that protects the plant tissues from the oxidative stress triggered by pathogen attack [16], but it also increases the nutraceutical value of treated plants [17].…”

Biocontrol Potential of Trichoderma Ghanense and Trichoderma Citrinoviride toward Pythium aphanidermatum

“…The impact of Trichoderma isolates on electrolyte leakage of P. aphanidermatum was studied as described previously [63,64]. 5 mm mycelial discs of Trichoderma isolates (3-dayold, previously grown on PDA) were transferred into 50 mL sterile conical flasks containing 5 of 16 25 mL potato dextrose broth (PDB, Sigma Aldrich, MO, USA) and, subsequently, incubated at 27 • C in a shaker for 7 days.…”

Optimization of culture conditions for the production, antifungal activity and characterization of secondary metabolites of <i>Trichoderma longibrachiatum</i>

“…In fully scan acquisition mode, the Electron Impact (EI) mass scan (m/s) range was 40-450 Da. (Muhammad et al, 2023).…”