Plant diseases cause losses of approximately 16% globally. Thus, management measures must be implemented to mitigate losses and guarantee food production. In addition to traditional management measures, induced resistance and biological control have gained ground in agriculture due to their enormous potential. Endophytic fungi internally colonize plant tissues and have the potential to act as control agents, such as biological agents or elicitors in the process of induced resistance and in attenuating abiotic stresses. In this review, we list the mode of action of this group of microorganisms which can act in controlling plant diseases and describe several examples in which endophytes were able to reduce the damage caused by pathogens and adverse conditions. This is due to their arsenal of molecules generated during the interaction by which they form a kind of biological shield in the plant. Furthermore, considering that endophytic fungi can be an important tool in managing for biotic and abiotic stresses due to the large amount of biologically active substances produced, bioprospecting this class of microorganisms is tending to increase and generate valuable products for agriculture.

The induction of resistance is an important strategy in integrated plant disease management. This strategy has a great potential to be adopted by farmers, motivated by the worldwide demand for a reduced pesticide use in food production. Studies have shown that resistance inducers are effective against a wide variety of pathogens, including Phakopsora pachyrhizi, the causal agent of Asian soybean rust. This review aims to synthesize current knowledge on the use of induced resistance for soybean rust management. Special emphasis is placed on commercially available products and potential resistance inducers described in the literature. Finally, perspectives and challenges regarding the use of resistance inducers for soybean rust management are highlighted.

Plant diseases cause losses of approximately 16% globally. Thus, management measures must be implemented to mitigate losses and guarantee food production. In addition to traditional management measures, resistance induction and biological control have gained ground in agriculture due to their enormous potential. Endophytic fungi colonize plant tissues internally and have the potential to act as biological control agents, as elicitors in the process of resistance induction and in attenuating abiotic stresses. In this review, we list the action of this group of microorganisms as potential agents which can act in controlling plant diseases and describe several examples in which endophytes were able to reduce the damage caused by pathogens and adverse conditions. This is due to their arsenal of molecules generated during the interaction by which they form a kind of biological shield in the plant. Studies on these microorganisms have grown due to the existing diversity and the multiple benefits they can offer. Finally, considering that endophytic fungi can be an important tool in managing diseases due to the large amount of biologically active substances produced, bioprospecting this class of microorganisms is tending to increase and generate valuable products.

Agradeço primeiramente a Deus, meu grande protetor e que me concede as graças diárias para seguir neste caminhada. Agradeço, em especial, ao Prof. Dr. Sérgio Florentino Pascholati pelo conhecimento repassado, compreensão, dedicação e por sua admirável forma de conduzir o convívio e a pesquisa com seus orientados. Ao Laboratório de Produção de Sementes (ESALQ/USP), especialmente a Prof a Dra. Ana D. L. Novembre pelas sugestões e disponibilização do espaço para a realização das análises. Aos meus pais, João Adelino de Paula e Néva Demartini de Paula, ao meu irmão, Kaciano de Paula e a minha cunhada, Adriane Reis, por apoiarem as minhas decisões incondicionalmente e por sempre me auxiliarem em tudo o que precisei. À minha namorada, Aline Fachin Martíni, por todo o auxílio, compreensão e atenção dispensados a mim. E, por entender minha ausência em muitos momentos importantes. Muito obrigado!

No abstract

No abstract

Aims Leifsonia xyli subsp. xyli (Lxx) is the most common sugarcane bacterial pathogen that affects plant development and primary metabolism. For example, cysteine and methionine are sulfur-containing essential amino acids used for bacterial growth and the title of Lxx in sugarcane plants might affect sulfur metabolism. The goal of this study were to evaluate how the increase in bacterial titers affects nutritional status and sulfur metabolism in sugarcane. Methods: The study was carried out with a susceptible sugarcane (Saccharum officinarum) genotype CB49260, with low and high Lxx titers, evaluating the mineral status and levels of primary metabolites. Results: Plants with high Lxx titers increased leaf sulfur content (S) compared to plants with low Lxx titers where plants with high Lxx titers displayed increased levels of sulfate, sucrose, maltose, raffinose, shikimic acid, malate, putrescine, glycerol, and, erythritol but decreased levels of methionine and glutathione in leaves. In the culm, plants with high Lxx titers displayed increased contents of maltose but decreased levels of threonine, ornithine, phenylalanine and myo-inositol when compared with plants with low Lxx titers. Conclusions: This study thus demonstrated that high bacterial titers increase sulfur demand in sugarcane. However, the increase in S content in the leaf did not result in higher sulfur assimilation, which was verified by increases sulfate level and decreases in methionine and glutathione levels. Therefore, our study showed that plant metabolism fails to meet the increased sulfur organic compound demand due to lower methionine and glutathione biosynthesis and methionine catabolism to putrescine biosynthesis in the leaves.