The authors have investigated the effects of different doses of mineral fertilizers combined with co-inoculation of Bacillus subtilis and Trichoderma asperellum to promote plant growth and use efficient nutrients in a plant Urochloa (Syn. Brachiaria) brizantha cv. Marandu. Individual experiments with doses of the nutrients nitrogen (N), phosphorus (P), and potassium (K) were carried out. The experiment was conducted in a completely randomized design, factorial 35. With the treatments: control noninoculation, inoculation with Bacillus subtilisUFRA-92, and coinoculation (MIX) with T. asperellum (UFRA-06, UFRA-09, UFRA-12, and UFRA-52)+B. subtilis x nutrient omissions (0, 25, 50, 75, and 100). Each treatment had five replications. Biometric parameters, nutrient content, and nutrient use efficiency were evaluated. The results showed that the inoculants promoted growth in Marandu grass. The use of inoculants promoted growth and increased N, P, and K uptake by Marandu grass. Co-inoculation changed leaf area, shoot length, elongation rate, and leaf appearance for N and K and root dry mass for P. In addition, the co-inoculation combined with doses of 75 of N, 50 of P, and 50 of K increased the nutritional content of the leaves by 256 of N, 280 of P, and 29 of K and provided greater agronomic efficiency, with increments of 462 of N, 544 of P, and 177 of K, compared to the control treatment. We present the potential of co-inoculation of B. subtilis and T. asperellum to promote the growth of Urochloa under reduced fertilizer application. There was an improvement in plant growth and nutrient use efficiency.

Lateritic duricrusts cover iron ore deposits and form spatially restricted, unique canga ecosystems endangered by mining. Iron cycling, i.e., the dissolution and subsequent precipitation of iron, is able to restitute canga duricrusts, generating new habitats for endangered biota in post-mining landscapes. As iron-reducing bacteria can accelerate this iron cycling, we aim to retrieve microbial enrichment cultures suitable to mediate the large-scale restoration of cangas. For that, we collected water and sediment samples from the Carajás National Forest and cultivated the iron-reducing microorganisms therein using a specific medium. We measured the potential to reduce iron using ferrozine assays, growth rate and metabolic activity. Six out of seven enrichment cultures effectively reduced iron, showing that different environments harbor iron-reducing bacteria. The most promising enrichment cultures were obtained from environments with repeated flooding and drying cycles, i.e., periodically inundated grasslands and a plateau of an iron mining waste pile characterized by frequent soaking. Selected enrichment cultures contained iron-reducing and fermenting bacteria, such as Serratia and Enterobacter. We found higher iron-reducing potential in enrichment cultures with a higher cell density and microorganism diversity. The obtained enrichment cultures should be tested for canga restoration to generate benefits for biodiversity and contribute to more sustainable iron mining in the region.

Carajasia cangae (Rubiaceae) is a narrow endemic species from the canga ecosystems of the Carajás National Forest that is facing extinction due to a limited range and habitat disturbance from hydroclimatological changes and mining activities. This study examines the influence of rhizospheric and endophytic bacteria on C. cangae seed germination to support conservation efforts. Soil samples, both rhizospheric and non-rhizospheric, as well as plant root tissues, were collected. Bacteria from these samples were subsequently isolated, cultured, and identified. DNA sequencing revealed the presence of 16 isolates (9 rhizospheric and 7 endophytic), representing 19 genera and 6 phyla: Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes, Bacteroidetes, and Chloroflexi. The endophytic isolates of Bacillus and the rhizospheric isolates of Planococcus and Lysinibacillus reduced the median germination time and initiation time, while the rhizospheric isolates Serratia and Comamonas increased the germination time and decreased the germination percentage in comparison to the control sample. These findings emphasize the crucial role of endophytic bacteria in the germination of C. cangae and highlight isolates that could have beneficial effects in the following stages of plant growth. Understanding the impact of endophytic and rhizospheric bacterial isolates on seed germination can enhance conservation efforts by shortening the germination period of this species and thereby improving seedling production. Additionally, this knowledge will pave the way for future research on the role of bacteria in the establishment of C. cangae.

Physiology and nutritional contents of lettuce (Lactuca sativa L.) plants induced by Pseudomonas fluorescens / Fisiologia e conteúdo nutricional de plantas de alface (Lactuca sativa L.) induzidas por Pseudomonas fluorescensv

Cave microbiomes represent a rich yet understudied source of chemical diversity with biotechnological properties. Microorganisms in these environments thrive under extreme conditions such as darkness, oligotrophy, and high concentrations of inorganic matter like iron ore. In this study, sediment samples were collected from the aphotic zone of a ferruginous cave in the National Forest of Carajás (Brazilian Amazon). Eight bacterial strains were isolated and taxonomically classified using 16S rRNA gene sequencing, revealing five genera: Serratia , Bacillus , Enterococcus , Aneurinibacillus , and Comamonas . Crude extracts from liquid cultures were analyzed using untargeted LC–MS/MS and processed through feature‐based molecular networking on the GNPS platform. The resulting network highlighted the production of structurally similar compound classes across different genera, including cyclopeptides, cholic acid derivatives, and indole alkaloids. Crude extracts were tested for cytotoxicity against HCT‐116 and 501mel tumor cell lines, with significant inhibition observed for extracts from Aneurinibacillus , Comamonas , and Enterococcus . Multivariate analysis linked cyclopeptide derivatives to cytotoxic activity. This study offers one of the first insights into the chemical potential of cave‐dwelling bacteria in Brazil and underscores their promise for future biotechnological exploration.