Trichoderma spp. Genes Involved in the Biocontrol Activity Against Rhizoctonia solani

Abstract

Rhizoctonia solani is a pathogen that causes considerable harm to plants worldwide. In the absence of hosts, R. solani survives in the soil by forming sclerotia, and management methods, such as cultivar breeding, crop rotations, and fungicide sprays, are insufficient and/or inefficient in controlling R. solani. One of the most challenging problems facing agriculture in the twenty-first century besides with the impact of global warming. Environmentally friendly techniques of crop production and improved agricultural practices are essential for long-term food security. Trichoderma spp. could serve as an excellent example of a model fungus to enhance crop productivity in a sustainable way. Among biocontrol mechanisms, mycoparasitism, competition, and antibiosis are the fundamental mechanisms by which Trichoderma spp. defend against R. solani, thereby preventing or obstructing its proliferation. Additionally, Trichoderma spp. induce a mixed induced systemic resistance (ISR) or systemic acquired resistance (SAR) in plants against R. solani, known as Trichoderma-ISR. Stimulation of every biocontrol mechanism involves Trichoderma spp. genes responsible for encoding secondary metabolites, siderophores, signaling molecules, enzymes for cell wall degradation, and plant growth regulators. Rhizoctonia solani biological control through genes of Trichoderma spp. is summarized in this paper. It also gives information on the Trichoderma-ISR in plants against R. solani. Nonetheless, fast-paced current research on Trichoderma spp. is required to properly utilize their true potential against diseases caused by R. solani.

Trichoderma- from lab bench to field application: Looking back over 50 years

“…MAPkinase TVK1 characterized in T. asperellum, T. atroviride, and T. virens mediated the transfer of information from sensors, regulate signaling mechanisms, cellular responses in plant roots, and increased biocontrol effectively against R. solani Contreras-Cornejo et al, 2016). Similarly, in another study, root inoculation of A. thaliana with T. asperelloidesT203 triggered rapid increase in the expression of transcription factors, that is, WRKY18, WRKY40, WRKy60, and WRKY33 exerted positive role in JA-mediated defense (Brotman et al, 2013;Abbas et al, 2022).…”

“…Survivability of Trichoderma species in soil after application is basically mediated by hyphae, aggregate, or mycelial fragments, resting structure such as chlamydospores and conidia (Papavizas et al, 1984). Persistence of conidia lasted up to 110-113 days without any amendments or decreased initially, then stabilized up to 1/10 th of original population in soil for 24 months (Papavizas and Lumsden, 1982;Abbas et al, 2022).…”

Global distribution, traditional and modern detection, diagnostic, and management approaches of Rhizoctonia solani associated with legume crops

“…Rhizoctonia solani causes severe diseases such as blights (web and foliar), damping-off, and rots (seed, stem, root, crown, collar, and hypocotyl) in alfalfa, soybean, chickpea, pea, common beans, and peanuts ( Basbagci and Dolar, 2020 ). The geographical distribution and disease severity of R. solani associated with legume crops are shown in Figure 1 ( Abbas et al, 2022b ). R. solani is causing severe yield losses and various diseases in legume crops in different countries, as shown in Table 1 .…”

“…Likewise, each anastomosis group (AGs) of R. solani requires a certain temperature to cause legume disease. R. solani also infects legumes at cold temperatures (15–18°C), which slows down the growth of their seedlings ( Abbas et al, 2022b ). It is common for fields to need to be replanted if there are missing stands due to seed decay or pre-emergence damping off.…”

“…Seeds infected with R. solani are unlikely to germinate; even if they do, the resulting seedlings will likely die shortly after or shortly after emergence. Recurring sclerotia arises, completing the disease cycle as shown in Figure 3 , and may survive for years under extreme environments such as extreme heat or cold, prolonged periods without food or water, the presence of harsh chemicals, or high levels of radiation ( Abbas et al, 2022b ).…”