Emergência e análise ultraestrutural de plântulas de soja inoculadas com Sclerotinia sclerotiorum sob efeito da aplicação de Trichoderma harzianum

Abstract

A elevada susceptibilidade da soja ao mofo-branco tem impactado negativamente a sua produtividade. Atualmente métodos de controle biológico como o uso de Trichoderma spp. têm proporcionado alternativas ao controle químico, com menor impacto ambiental e favorecimento do desenvolvimento vegetal. Objetivou-se avaliar os efeitos de T. harzianum sobre a emergência de sementes de soja inoculadas com Sclerotinia sclerotiorum; além de verificar a interação entre os fungos e com a soja, por meio da microscopia eletrônica de varredura (MEV ABSTRACTThe high susceptibility of soybean to white mold has negatively impacted its productivity. Currently, biological control methods, such as the use of Trichoderma spp., have provided alternatives to chemical control, as they promote less environmental impact and favor the plant growth. The aim of this study was to evaluate the effects of T. harzianum on the emergence of soybean seeds inoculated with Sclerotinia sclerotiorum, besides identifying the interaction between fungi and soybeans by means of scanning electron microscopy (SEM). Soybean seeds were subjected to the following treatments: 1. Without S. sclerotiorum, in PDA+Mannitol; 2. With S. sclerotiorum, in PDA+Mannitol; 3. With Ecotrich ® WP and without S. sclerotiorum, in PDA+Mannitol; 4. Silva, F.F.; Castro, E.M.; Moreira, S.I.; Ferreira, T.C.; Lima, A.E.; Alves, E. Emergence and ultrastructural analysis of soybean seedlings inoculated with Sclerotinia sclerotiorum under the effect of Trichoderma harzianum application. Summa Phytopathologica, v.43, n.1, p.41-45, 2017. With S. sclerotiorum and Ecotrich ® WP, in PDA+Mannitol. The emergence test was conducted on trays with sterile sand at 25 °C for 8 days. Then, the vegetative organs of emerged seedlings were sectioned to evaluate, by scanning electron microscopy (SEM), T. harzianum potential to parasitize and inhibit S. sclerotiorum. In fact, the white mold is capable of colonizing and deteriorating all soybean seeds. T. harzianum is effective in colonizing the root system of soybeans but does not contribute to emergence, compared to control. Based on the ultrastructural analysis, mycoparasitism of T. harzianum and S. Sclerotiorum was evidenced, but the control of the causal agent of white mold was not as effective as shown in other studies.

Combined Effects of Biological and Chemical Treatment on Rice Seed Physiological and Sanitary Quality

“…P. fluorescens produces 2,4-diacetylphloroglucinol, a prominent antimicrobial that inhibits the growth of several phytopathogenic bacteria, oomycetes, and fungi (Couillerot et al, 2011). T. harzianum secrets hydrolytic enzymes, produces fungistatic compounds (Contreras-Cornejo, Macías-Rodriguez, Del-Val, & Larsen, 2016), and parasitizes other fungi (Silva et al, 2017). All these data support our findings regarding fungi control on rice seeds using biological control (Table 3).…”

Chemical composition and in vitro inhibitory effects of essential oils from fruit peel of three Citrus species and limonene on mycelial growth of Sclerotinia sclerotiorum

“…White mold development is favored by certain conditions, such as high humidity and low/moderate temperatures. It may be controlled, mainly by fungicide application, which depends on several factors, such as soil inoculum density, phases of the epidemic, fungicide coverage of plants, number of pulverization steps, fungitoxicity doses, application time, volume and equipment, plant spacing, besides disease incidence and severity (Silva et al, 2017).…”

Production of Tamarindus indica L. seedlings submitted to substrates and pre-germination methods

“…The behavior observed in the water-imbibed seeds containing the Trichodermas on the production of biomass may be associated to its effect on the plant, which, when colonizing the roots, the epidermis and the cortex cells, stimulates the growth and development of plants, due to the solubilization of phosphate, micronutrients and also by the production of auxin analogues (Carvalho et al 2011, Silva et al 2017. In addition, the seedling germination and emergence correspond to the stages of the life cycle of a plant in which it is most vulnerable to environmental stresses and pest and disease attacks.…”