Induction of phytoalexins and proteins related to pathogenesis in plants treated with extracts of cutaneous secretions of southern Amazonian Bufonidae amphibians

• Published in: PloS one Vol. 14; no. 1; p. e0211020
• Main Authors: Deice Raasch-Fernandes, Livia, Bonaldo, Solange Maria, de Jesus Rodrigues, Domingos, Magela Vieira-Junior, Gerardo, Regina Freitas Schwan-Estrada, Kátia, Rocco da Silva, Camila, Gabriela Araújo Verçosa, Ana, Lopes de Oliveira, Daiane, Wender Debiasi, Bryan
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 17.01.2019; Public Library of Science (PLoS)
• Subjects: Acids; Agricultural chemicals; Agrochemicals; Amphibia; Amphibian Proteins - chemistry; Amphibian Proteins - pharmacology; Amphibians; Animals; Bioactive compounds; Biological activity; Biology and Life Sciences; Bodily secretions; Bufonidae; Bufonids; Cane toad; Chemical properties; Cotyledons; Crop diseases; Crops; Cultivars; Disease control; Environmental science; Enzymatic activity; Enzyme activity; Enzymes; Gene expression; Genotypes; Glycine max - metabolism; Hypocotyls; Kinases; Medicine and Health Sciences; Metabolites; Natural products; Organic chemistry; Pathogenesis; Peroxidase; Pesticides; Phaseolin; Physiological aspects; Physiology; Phytoalexins; Plant Diseases; Plant extracts; Plant metabolites; Plant protection; Plants (botany); Polyphenol oxidase; Proteins; Pterocarpans - biosynthesis; Research and Analysis Methods; Rhaebo guttatus; Rhinella marina; Secretions; Sesquiterpenes - chemistry; Sesquiterpenes - pharmacology; Skin - chemistry; Skin - metabolism; Sorghum; Soybeans; Species; Synthesis; Brazil
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0211020

Cutaneous secretions produced by amphibians of the family Bufonidae are rich sources of bioactive compounds that can be useful as new chemical templates for agrochemicals. In crop protection, the use of elicitors to induce responses offers the prospect of durable, broad-spectrum disease control using the plant's own resistance. Therefore, we evaluated the potential of methanolic extracts of cutaneous secretions of two species of amphibians of the family Bufonidae found in the Amazon biome-Rhaebo guttatus (species 1) and Rhinella marina (species 2)-in the synthesis of phytoalexins in soybean cotyledons, bean hypocotyls, and sorghum mesocotyls. Additionally, changes in the enzyme activity of β-1,3-glucanase, peroxidase (POX), and polyphenol oxidase (PPO) and in the total protein content of soybean cotyledons were determined. In the soybean cultivar 'TMG 132 RR', our results indicated that the methanolic extract of R. guttatus cutaneous secretions suppressed glyceollin synthesis and β-1,3-glucanase activity and increased POX and PPO activities at higher concentrations and total protein content at a concentration of 0.2 mg/mL. On the other hand, the methanolic extract of R. marina cutaneous secretions induced glyceollin synthesis in the soybean cultivars 'TMG 132 RR' and 'Monsoy 8372 IPRO' at 0.1-0.2 mg/mL and 0.2 mg/mL, respectively. The methanolic extract of R. marina cutaneous secretions also increased the specific activity of POX and PPO in 'Monsoy 8372 IPRO' and 'TMG 132 RR', respectively, and decreased the activity of β-1,3-glucanases in 'Monsoy 8372 IPRO'. At 0.3 mg/mL, it stimulated phaseolin synthesis. The extracts did not express bioactivity in the synthesis of deoxyanthocyanidins in sorghum mesocotyls. The study in soybean suggests that the bioactivity in defense responses is influenced by cultivar genotypes. Therefore, these results provide evidence that extracts of cutaneous secretions of these amphibians species may contribute to the bioactivity of defense metabolites in plants.