Gilvan Ferreira da Silva

Sclerotium rot, caused by Agroathelia rolfsii, is one of the main soil-borne diseases that limit tomato production. This study evaluates the efficacy of Amazonian Trichoderma species in controlling Sclerotium rot and stimulating plant development under field conditions in Manaus, Brazil. We used six Trichoderma isolates based on their previously evaluated performance under greenhouse conditions. The incidence of Sclerotium rot, tomato fruit production, and functional attributes of the isolates were evaluated. The isolates reduced the incidence of Sclerotium rot by up to 75 percentage points and also increased fruit production. T. rugulosum showed the best performance as it significantly reduced the incidence of Sclerotium rot and improved fruit yield. Although no differences were found in biomass allocation to plant organs, T. endophyticum, T. agriamazonicum, and T. asperelloides showed production of indolic compounds in vitro. The results highlight the potential of Amazonian Trichoderma isolates as biofungicides for use in sustainable tomato cultivation. In addition, we demonstrated the potential of Amazonian Trichoderma species both to reduce the incidence of Sclerotium rot and to increase fruit production. By reducing the use of synthetic agrochemicals, the use of Trichoderma promotes healthier and more sustainable agricultural practices.

Biosurfactants are amphiphilic microbial metabolites with potential to reduce surface and interfacial tension and to promote emulsification. This study investigated the biosynthetic potential, emulsifying activity, and metabolomic profile of Bacillus subtilis subsp. subtilis INPA R296 cultivated in media supplemented with residual soybean oil. Phylogenomic analyses supported the taxonomic placement of the strain close to Bacillus subtilis subsp. subtilis 168 ^T . Genome mining predicted 11 biosynthetic gene clusters (BGCs), including NRPS clusters related to surfactin and fengycin biosynthesis. Synteny analyses indicated conservation of these clusters among phylogenetically related Bacillus strains. Functional assays showed that culture-medium composition influenced cell growth, emulsification indices, and emulsifying activity. UHPLC-HRMS/MS combined with molecular networking enabled the putative annotation of metabolites belonging to several chemical classes, including cyclic lipopeptides, N -acyl amino acids, and oxylipins. The main contribution of this study is the integrated evaluation of genomic biosynthetic potential, emulsifying activity, and putative metabolite annotations in strain INPA R296 cultivated with a low-cost agro-industrial residue. Because no biosurfactant yield, surface/interfacial tension, authentic-standard validation, or structural isolation was performed, the results demonstrate emulsifying potential and the occurrence of putatively annotated amphiphilic metabolites rather than confirmed biosurfactant production. These findings identify INPA R296 as a target for further investigation of amphiphilic metabolites with potential biotechnological applications.

Sclerotium rot, caused by Agroathelia rolfsii, is one of the main soilborne diseases that limit plant growth and tomato yield. This study evaluated the efficacy of Amazonian Trichoderma species to control sclerotium rot, and promote plant growth under field conditions, in Manaus, Brazil. We used six species (isolates) of Trichoderma based on their previously assessed performance in field trials. The incidence of sclerotium rot, tomato fruit yield and the production of indoleacetic acid (IAA) and siderophores were evaluated. The isolates reduced the incidence of sclerotium rot by up to 75% and also increased fruit yield. T. rugulosum had the best performance, as it greatly reduced sclerotium rot incidence and improved fruit yield. Although no differences were found in biomass allocation to plant organs, T. endophyticum, T. agriamazonicum, and T. asperelloides showed high production of IAA. The results highlight the potential of Amazonian Trichoderma isolates as bio fungicides to be used in sustainable cultivation of tomato. Furthermore, we show the potential of Amazonian species of Trichoderma to both reduce the incidence of sclerotium rot, and to increase the production of bioactive compounds that stimulate plant growth. By reducing the use of synthetic agrochemicals, the use of Trichoderma promotes healthier and more sustainable agricultural practices.

Trichoderma is a cosmopolitan genus widely used in agriculture due to its beneficial traits that promote plant growth and provide sustainable crop protection. Over 450 valid Trichoderma species have been described, with increasing whole-genome data showing extensive enzymatic repertoires and biosynthetic potential. However, the Amazonian biome remains underexplored for Trichoderma diversity despite its megadiversity. In this study, 44 Trichoderma strains were isolated from sediments collected during a systematic expedition along three major white-water Amazonian rivers (Juruá, Madeira, and Purus). Initial molecular barcoding using tef1-α sequences identified 14 species, with Trichoderma lentiforme being ubiquitously distributed across all three river systems. Isolates exhibiting 95% mycelial growth inhibition against multiple Colletotrichum species. Comparative genomic analyses revealed diverse CAZyme arsenals enriched in glycoside hydrolases associated with mycoparasitism (GH16, GH18, GH72) and lignocellulose degradation, with T. labreaense TM26 exhibiting particularly high chitinase content and T. juburiaense TM67 showing elevated β-glucanase levels. Genome mining identified biosynthetic gene clusters encoding bioactive secondary metabolites, including verticillins, ilicicolins, chaetoglobosins, harzianopyridone, and brefeldin A, compounds with established antifungal, antibacterial, and cytotoxic activities. This study provides a taxonomic and genomic survey of Trichoderma from Amazonian white-water river sediments, describing five novel species and highlighting this frontier ecosystem as an important but undersampled source of fungal biodiversity.

The genus Streptomyces is recognized as a source of secondary metabolites (SMs) with applications in medicine, industry, and agriculture. This study presents the description and characterization of a new Streptomyces species, isolated from sediments of the Madeira River in the Brazilian Amazon. Four strains (CPAA MAD 27, CPAA MAD 39, CPAA MAD 42, and CPAA MAD 51) were obtained from sampling sites distributed along the river. The strains were analyzed for morphological, phenotypic, and biochemical characteristics, as well as their potential for SM production using genome mining. Phylogenetic and phylogenomic analyses indicated that Streptomyces murinus is the most closely related species; however, the dDDH value of 55% and ANI of 94%, combined with biochemical analysis, support the proposal of the isolates as a new species, herein named Streptomyces amazonensis . This species exhibits adaptability to diverse environmental conditions, growing across a wide range of pH values (4–11) and temperatures (15–40 °C), with optimal growth at 35 °C and pH 8, and utilizing various carbon sources, including L-arabinose, unlike S. murinus . Genomic analysis revealed 39 to 46 biosynthetic gene clusters (BGCs) per strain, related to polyketides, nonribosomal peptides, and ribosomally synthesized and post-translationally modified peptides (RiPPs). Notably, BGCs showed high similarity to thioligamide (antitumor) and tetracenomycin (antibiotic) metabolites. Additionally, numerous BGCs with matches in the MIBiG database were identified, suggesting genomic potential related to the biosynthesis of molecules of scientific interest. This discovery expands our understanding of Amazonian microbial diversity and offers new prospects for the bioprospecting of natural products, highlighted by the unexplored biosynthetic potential of S. amazonensis for the development of new natural compounds.

Postharvest diseases represent a critical challenge for global agriculture, resulting in substantial economic losses and threatening worldwide food security. Species of the genus Colletotrichum stand out among the main phytopathogens for being responsible for up to 40% of postharvest losses in various crops, including Capsicum species. This study evaluated the antifungal activity of two Streptomyces strains isolated from Amazonian sediments against different Colletotrichum species, with a focus on C. scovillei, the causal agent of anthracnose in Capsicum chinense fruits. Multilocus phylogenetic analyses indicated that strain APUR 32.5 possibly represents a new species, while MPUR 40.3 was identified as Streptomyces murinus. Both strains exhibited in vitro antifungal activity against seven Colletotrichum species, with inhibition percentages ranging from 56.3% to 88.6%. In fruit bioassays, S. murinus MPUR 40.3 reduced the incidence of anthracnose by 95%, while Streptomyces sp. APUR 32.5 achieved a 39.25% reduction. Scanning electron microscopy revealed complementary mechanisms of antifungal action, with MPUR 40.3 acting during the early infection stages through germination tube lysis, while APUR 32.5 targeted established mycelial structures through hyphal degradation. Additionally, both strains demonstrated plant growth-promoting capacity and exhibited biotechnologically relevant characteristics, including production of hydrolytic enzymes, siderophores, and phosphate solubilization ability. These results highlight the biotechnological promise of these Amazonian isolates as multifunctional agents for the sustainable management of anthracnose in Capsicum peppers.

Camu-camu (Myrciaria dubia (Kunth) McVaugh) is an Amazonian fruit with high economic potential due to its reported health-promoting properties, including elevated antioxidant and anti-inflammatory compound levels. Since 2018, anthracnose-like lesions, starting as small dark spots and coalescing into large irregular or circular lesions, were observed in up to 60% of camu-camu plants in an experimental field located in the city of Boa Vista, Roraima, Brazil (2°52'20.7″ N; 60°42'44.2″ W) and in a natural population in Rorainópolis, Roraima, Brazil (0°54'128″ N,60°36'226″ W). Fifty symptomatic leaves were collected from 10 plants. Small (5×5 mm) lesion tissue fragments were surface disinfected in 70% ethanol (1 min), 2.5% sodium hypochlorite (1 min), rinsed in sterile water, and placed on water agar. After 4 days at 25°C, mycelium was transferred to potato dextrose agar (PDA). After 7 days, 10 morphologically similar isolates were obtained, showing grayish-white colonies with orange spore masses. Conidia were hyaline, unicellular, cylindrical, smooth-walled, straight with rounded apices, measuring 15.3 ± 0.8 × 6.95 ± 1.4 μm (n = 30). Appressoria were brown, irregular or ovoid, measuring 6.4 ± 1.5 × 4.9 ± 1.2 μm (n = 30). Single-spore cultures were deposited in the EMBRAPA Roraima Microorganism Culture Collection. Four representative isolates (MTG07, MTG08 from Boa Vista; DXV01, DXV02 from Rorainópolis) were selected for phylogenetic and pathogenicity analysis. Total DNA was extracted and portions of actin (ACT), calmodulin (CAL), chitin synthase 1 (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and β-tubulin 2 (TUB2) genes were amplified (Weir et al. 2012) and Sanger sequenced (GenBank accession numbers ACT: PV463490-PV463493; CAL: PV463498-PV463501; CHS-1: PV055675-PV055678; GAPDH: PV430301-PV430304; TUB2: PV463494-PV463497). Sequences showed 96 to 99% identity with sequences of Colletotrichum siamense published in GenBank. Phylogenetic Bayesian inference analysis based on a combined data set showed that the isolates clustered with the ex-holotype specimen of C. siamense (ICMP 18578) with high support (posterior probability = 0.98). To confirm pathogenicity, five seedlings of camu-camu per isolate were sprayed with 106 conidia/mL spore suspension (15 mL/plant). Control seedlings were sprayed with sterile water. All seedlings were covered with plastic bags 24 h after inoculation and maintained at 27°C in a greenhouse with a 12-h photoperiod. After 6 days, inoculated leaves exhibited small dark brown spots with yellow halo, which enlarged and coalesced into regular or irregular brown necrotic lesions. The control plants showed no symptoms. The pathogenicity test was performed twice with similar results. The fungus was successfully reisolated from the inoculated leaves and its identify was confirmed by cultural morphology and DNA sequence. C. siamense is a known anthracnose agent on diverse hosts (Weir et al. 2012), but in camu-camu, only C. gloeosporioides, C. aeschynomenes, C. tropicale, and C. theobromicola (Perez et al., 2006; Matos et al., 2020; Sachet et al., 2024) have been reported. To our knowledge, this is the first report of C. siamense causing anthracnose in camu-camu. The identification of the pathogen enables future research on management strategies, as this pathogen can cause serious damage to camu-camu production in the region.

Background/Objectives: Lipoprotein lipase (LPL) is a key enzyme in lipid metabolism, crucial for the hydrolysis of triglycerides in lipoproteins and maintaining lipid homeostasis in vertebrates. This study aims to characterize the lipoprotein lipase genes in the tambaqui (Colossoma macropomum) genome, investigating their evolutionary history from a phylogenomic perspective. Methods: Phylogenetic and syntenic analyses were used to identify the lpl gene copies in the tambaqui genome and expression patterns were examined across different tissues. A comparative analysis with lpl genes from other vertebrates was also conducted to assess evolutionary relationships and functional diversification. Results: We identified three lpl gene copies in the tambaqui genome: lpl1a, lpl1b, and the lesser-known member of the lipoprotein lipase subfamily, lpl2a. These proteins possess conserved sites essential for lipoprotein lipase function, with variations that may affect their physicochemical properties and lipolytic activity. Key amino acid variations, such as in the lid region and glycosylation sites, were observed among orthologs. Gene expression analysis showed high lpl1a and lpl2a expression in the liver, and lpl1b expression in the gonads, suggesting tissue-specific roles. Comparative analysis revealed distinct expression patterns among teleost fish, with tambaqui exhibiting a unique profile consistent with its migratory lifestyle and varied diet. Conclusions: This study offers new insights into the evolution and functional diversification of lipoprotein lipases in vertebrates, highlighting the complexity of lipid metabolism in fish. These findings contribute to understanding the adaptability of teleost fish to diverse environments and lay the foundation for future research in lipid metabolism regulation, including Neotropical species, with potential applications in aquaculture and conservation.