<i>Muscodor coffeanum</i> Enhances Tomato Yield and Fruit Quality Under <i>Xanthomonas vesicatoria</i> Infection

ABSTRACT Tomatoes are an economically significant crop in Brazil. However, their cultivation is often hindered by diseases, including bacterial black spot caused by Xanthomonas vesicatoria , which leads to significant yield losses. Endophytic fungi in the genus Muscodor are promising biological control agents because they produce antimicrobial volatile organic compounds and modulate plant metabolite biosynthesis, promoting growth and inducing disease resistance. This study evaluated the potential of M. coffeanum (CML 4009, CML 4011, CML 4014 and CML 4019), applied individually or in mixture via seed inoculation or foliar spray, to induce tolerance to X. vesicatoria and improve tomato yield and fruit quality. None of the M. coffeanum treatments significantly reduced disease severity compared with the positive control; however, foliar application of isolate CML 4009 resulted in a lower AUDPC among fungal treatments. Seed inoculation with the same isolate significantly increased total dry biomass and total fruit weight, as well as fruit length and width. Plants inoculated with M. coffeanum (CML 4009), either alone or in combination with other isolates, showed improved antioxidant properties, with lower IC 50 values in DPPH radical scavenging, higher total antioxidant capacity (TAC), and increased phenolic content. Fruit firmness was also enhanced in inoculated plants. The results confirm that M. coffeanum (CML 4009) enhances tomato vigour and fruit quality under pathogen pressure, primarily through improved plant performance rather than disease suppression.