Currently, the tropics harbor a wide variety of crops to feed the global population. Rapid population expansion and the consequent major demand for food and agriculture-based products generate initiatives for tropical forest deforestation, which contributes to land degradation and the loss of macro and micronative biodiversity of ecosystems. Likewise, the entire dependence on fertilizers and pesticides also contributes to negative impacts on environmental and human health. To guarantee current and future food safety, as well as natural resource preservation, systems for sustainable crops in the tropics have attracted substantial attention worldwide. Therefore, the use of beneficial plant-associated microorganisms is a promising sustainable way to solve issues concerning modern agriculture and the environment. Efficient strains of bacteria and fungi are a rich source of natural products that might improve crop yield in numerous biological ways, such as nitrogen fixation, hormone production, mobilization of insoluble nutrients, and mechanisms related to plant biotic and abiotic stress alleviation. Additionally, these microorganisms also exhibit great potential for the biocontrol of phytopathogens and pest insects. This review addresses research regarding endophytic and rhizospheric microorganisms associated with tropical plants as a sustainable alternative to control diseases and enhance food production to minimize ecological damage in tropical ecosystems.

The growing antimicrobial resistance and persistence of pathogenic microorganisms in infections–particularly in nosocomial infections–have become a major problem for public health worldwide. One of the main causes of these issues is the formation of biofilms, which are microbial communities associated with extracellular polymeric substances (EPS) that form a slimy extracellular matrix, causing the bacteria to become more tolerant to usual drugs in these structures. Thus, the search for new antibiofilm compounds is part of a strategy to deal with this problem. Endophytic microorganisms such as bacteria and fungi, mutualistically associated with plants, are sources of compounds with biological properties, including antimicrobials, and can be important allies in the synthesis of antibiofilm. These secondary metabolites can interfere with cell-to-cell communication and cell adhesion ability, promoting the dispersal of bacterial colonies and affecting biofilm. Since endophytes are cultivable in laboratory conditions, these microorganisms are environmentally friendly, as they do not contribute to pollution, are easy to handle and are produced on a large scale. Furthermore, metabolites from endophytes are of natural origin and may contribute to the reduced use of synthetic drugs. Considering these aspects, this chapter will focus on the characterization of endophytic microorganisms as potential active sources of antibiofilm and antimicrobial compounds with applications in medicine.

Promoção de crescimento de tangerina sunki via inoculação no substrato 2.4 Análise de características funcionais envolvidas na promoção de crescimento

O mangue é um ecossistema de transição entre o ambiente terrestre e o marinho, típico de regiões tropicais e subtropicais. O cerrado é um ecossistema caracterizado principalmente pelo bioma savana, que são zonas de transição entre prados e bosques e são ínsitos de regiões tropicais de estação seca. Nesses dois sistemas, diversos microrganismos já foram isolados, entre eles, os fungos endofíticos, capazes de produzir substâncias com atividades antimicrobianas e leishmanicidas. Com base nessas informações, esse trabalho teve como objetivo avaliar o potencial biotecnológico dos extratos brutos (EB) obtidos dos fungos endofíticos Diaporthe sp. e Pseudofusicoccum sp., isolados de mangue e cerrado brasileiros, respectivamente. Foram realizados in vitro ensaios antimicrobianos com patógenos humanos, ensaios leishmanicidas e ensaios citotóxicos. Nos ensaios antimicrobianos foi encontrada a concentração inibitória mínima de 50% (CIM50) entre 756 µg.mL-1 e 949 µg.mL-1 e a concentração inibitória mínima de 90% (CIM90) entre 3.940 e 3.980 µg.mL-1 para o EB do isolado do mangue. Para o EB isolado do cerrado foi encontrada CIM50 entre 4.228 µg.mL-1 e 29.630 µg.mL-1 e CIM90 entre 9.24 µg.mL-1 e 38.250 µg.mL-1. A concentração bactericida mínima (CBM) foi encontrada para o microrganismo Bacillus subtillis, na concentração de 10.000 µg.mL-1. Nos ensaios leishmanicidas, os resultados apresentam morte celular de 90% nas concentrações de 6.000 e 10.000 µg.mL-1 e de 80% na concentração de 4.000 µg.mL-1 para o EB do isolado do mangue. No EB do isolado do cerrado, os ensaios leishmanicidas apresentaram viabilidade celular acima de 90% nas concentrações de 20.000 e 40.000 µg.mL-1.  Para os ensaios de citotoxicidade no EB do isolado do mangue, foram apresentados viabilidade celular entre 55 e 73%. Para o isolado do cerrado foram apresentadas viabilidade celular entre 5,41 a 16,84%. Esses resultados reforçam o potencial biotecnológico dos microrganismos isolados de manguezais e cerrados, representado pelos isolados testados nesse trabalho.