AUTHOR=Imran Muhammad , Abo-Elyousr Kamal A. M. , Mousa Magdi A. A. , Saad Maged M. 

TITLE=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

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1192818

DOI=10.3389/fpls.2023.1192818

ISSN=1664-462X

ABSTRACT=<sec><title>Introduction</title><p><italic>Alternaria solani</italic> 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 <italic>Trichoderma</italic> spp. to control this disease.</p></sec><sec><title>Methods</title><p>Highly virulent <italic>A. solani</italic> strain and three <italic>Trichoderma</italic> fungal strains viz., <italic>T. harzianum</italic> (Accession No: MW590687), <italic>T. atroviride</italic> (Accession No: MW590689) and <italic>T. longibrachiatum</italic> (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”.</p></sec><sec><title>Results and discussion</title><p>The CFs of <italic>T. harzianum</italic>, <italic>T. longibrachiatum</italic>, and <italic>T. atroviride</italic> significantly inhibited the <italic>in vitro</italic> mycelial growth of <italic>A. solani</italic> (62.5%, 48.73%, and 57.82%, respectively, followed by control 100%). In the GC–MS analysis of <italic>Trichoderma</italic> CF volatile compounds viz., harzianic acid (61.86%) in <italic>T. harzianum</italic>, linoleic acid (70.02%) in <italic>T. atroviride</italic>, and hydroxymethylfurfural (68.08%) in the CFs of <italic>T. longibrachiatum</italic>, were abundantly present. Foliar application of CFs in the greenhouse considerably reduced the disease severity (%) in all treatments, viz., <italic>T. harzianum</italic> (18.03%), <italic>T. longibrachiatum</italic> (31.91%), and <italic>T. atroviride</italic> (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.</p></sec>