Trichoderma Isolates Inhibit Fusarium virguliforme Growth, Reduce Root Rot, and Induce Defense-Related Genes on Soybean Seedlings

Abstract

<jats:p> Sudden death syndrome (SDS) caused by Fusarium virguliforme is among the most important diseases affecting soybean in the United States. The use of biological control agents (BCAs) such as Trichoderma spp. can be a valuable resource to suppress F. virguliforme populations. Therefore, this research focused on screening possible BCAs against F. virguliforme and evaluating mycoparasitism and the induction of systemic resistance as mechanisms underlying the antagonistic activity of selected BCAs against F. virguliforme. In total, 47 potential BCAs, including 41 Trichoderma isolates and 6 Mortierella isolates, were screened in a dual-plate assay. The most effective isolates belonged to the Trichoderma harzianum species and were able to inhibit F. virguliforme radial growth by up to 92%. Selected Trichoderma isolates were tested in the greenhouse and in a microplot study. They reduced root rot caused by F. virguliforme when the plants were coinoculated with the pathogen and the BCA. The tested BCA’s ability to reduce F. virguliforme growth may be related to several mechanisms of action, including mycoparasitism and induction of defense-related genes in plants, as revealed by monitoring the expression of defense-related genes in soybean. Our results highlight the potential of native Trichoderma isolates to inhibit F. virguliforme growth and reduce SDS severity, providing the basis for future implementation of biological control in soybean production. More efforts are needed to implement the use of these approaches in production fields, and to deepen the current knowledge on the biology of these highly antagonistic isolates. </jats:p>

Microbial Communities Associated With Long-Term Tillage and Fertility Treatments in a Corn-Soybean Cropping System

“…Notably, ecological guilds belonging to the “pathotrophic mode” differed in abundance between tillage treatments; the abundance of “mycoparasites,” and “animal pathogens” increased, whereas that of “plant pathogens” declined in no-till soils. The turnover caused by tillage is in line with other studies indicating a positive correlation between the occurrence of AMF and mycoparasites often favored in carbon rich soil ( Veach et al, 2018 ; Pimentel et al, 2020 ). However, the relatively high abundance of plant pathogens in tilled soils is not consistent with other studies ( Steinkellner and Langer, 2004 ; Degrune et al, 2016 ).…”

Antagonistic Activity of Trichoderma spp. Against Fusarium oxysporum in Rhizosphere of Radix pseudostellariae Triggers the Expression of Host Defense Genes and Improves Its Growth Under Long-Term Monoculture System

“…Trichoderma spp. have been studied commonly because of its ability to inhibit soil-borne pathogens and have good plant defense responses (Papavizas, 1985;Hermosa et al, 2012;Pimentel et al, 2020). In this study, PCR-DGGE results showed significant shifts in Trichoderma community in the rhizosphere of R. pseudostellariae after extended monoculture ( Supplementary Figure 2 and Figure 2).…”

“…This symbiotic relationship can effectively protect the plant from pathogens (Mukherjee et al, 2018;Galletti et al, 2020). When Trichoderma interacts with plants, it induces the expression of genes involved in the defense responses of plants (Brotman et al, 2013;Mayo et al, 2016;Manganiello et al, 2018;De Palma et al, 2019;Pimentel et al, 2020) and promotes plant growth and root development (Hermosa et al, 2012). However, the role of root-associated mutualistic plant symbiont, Trichoderma spp., in activation of R. pseudostellariae immunity by triggering the expression of defense-related genes is never explored.…”

Current recommendations and novel strategies for sustainable management of soybean sudden death syndrome

“…Because of these properties, various investigations have evaluated the use of BCAs and their mode of action for the control of SDS. For example, Trichoderma harzianum and two arbuscular mycorrhizal fungus (AMF), Rhizophagus irregularis and R. intraradices , reduced SDS severity caused by F.v 78‐80 . On the other hand, plant growth‐promoting bacteria (PGPB) also proved to be effective in controlling SDS‐causing Fusarium species.…”

“…Regarding the mode of action, both T. harzianum and Lysobacter enzymogenes strain C3 directly suppress F.v . mycelial growth 78,82 . Additionally, T. harzianum induces the activation of defense responses in soybean plants, increasing the expression of defense‐related genes associated with the salicylic acid (SA) and jasmonic acid/ethylene (JA/ET) pathways.…”