Some endophytes can synthesize molecules that elicit the induction of plant resistance to infection by pathogens. The objective of this study was to demonstrate that protein fractions 42 and 75 from Bacillus amyloliquefaciens and Bacillus pumilus were capable of acting as elicitors of induced resistance in tomato plants against Xanthomonas vesicatoria, following partial resolution by gel-filtration chromatography. Tomato plants sprayed with protein fractions 42 and 75 reduced, respectively, 63.5 and 56.6% of bacterial spot, compared with control plants. Additionally, these fractions promoted the increase of peroxidase (POX) and polyphenol oxidase (PPO) enzyme activities in treated plants. In SDS-PAGE stained with silver nitrate, protein fractions 42 and 75 appeared as simple bands with estimated molecular mass of 28 and 43 kDa, respectively. We report the partial characterization of two macromolecules synthesized by endophytic bacteria that act as elicitors of systemic resistance in tomato against X. vesicatoria.

Endophytic bacteria Bacillus pumilus and Bacillus amyloliquefaciens, indigenous from tomato, were evaluated for their ability to induce resistance against bacterial speck in tomato plants. Plants grown from seeds that were bacterized with the two Bacillus species and inoculated with a green fluorescent proteinmarked Pseudomonas syringae pv. tomato NS4 displayed reduced disease severity when compared to control treatment (water). However, plants in an induced state had a slight negative effect on plant growth parameters such as plant height and plant dry weight. Under epifluorescence microscopy, on tomato phylloplane of plants grown from seeds bacterized with the bacilli, the GFP-marked strain population was drastically reduced and presented individual cells or few aggregates of the pathogen between the depressions along the junctions on the leaf surface. In addition, peroxidase (POX), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) enzyme activities were evaluated in plant extracts, and all showed increased activity. We report the ability of two Bacillus species in promoting the phenomenon of induced resistance in tomato plants by a significant increase in POX, PPO and PAL activities, which produced a protective effect in reducing disease severity in levels that reached 62%.

Dois antagonistas selecionados para o biocontrole da vassoura-de-bruxa do cacaueiro foram avaliados quanto à capacidade em ativar mecanismos de defesa de plantas contra patógenos. Para tanto, mudas seminais de cacaueiro "comum" foram cultivadas em casa-de-vegetação por 30 dias e expostas aos antagonistas aplicados a mudas de cacaueiro por atomização, individualmente e em associação. O primeiro par de folhas das mudas dos diferentes tratamentos foi coletado aos dois, quatro, 12 e 24 dias após a exposição aos antagonistas. Foi quantificada a atividade de peroxidases, polifenoloxidases, quitinases e beta-1,3-glucanases no material coletado. Observou-se um aumento na atividade de peroxidases e polifenoloxidases nos primeiros dias após a exposição das mudas, especialmente ao isolado Ac26. Não foi observado efeito aditivo ou sinergístico nas mudas expostas aos dois isolados simultaneamente.

Erwinia psidii Rodrigues Neto et al. is a plant-pathogenic bacterium that causes serious damage to eucalyptus, guava and papaya crops in tropical and subtropical conditions (Chai et al., 2017;Coutinho et al., 2011;Rodrigues Neto et al., 1983). In South America, the bacterial pathogen was reported causing dieback on eucalyptus species in Argentina, Uruguay (Coutinho et al., 2011) and Brazil (Arriel et al., 2014). In Brazil, the incidence of eucalyptus bacterial blight on susceptible genotypes can reach 30% of trees in a production field (Borges-Junior et al., 2020). Besides dieback, the pathogen can cause leaf hydrosis (i.e. water-soaking) close to midrib, stem canker and

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Endophytic bacteria Bacillus safensis RS95 and Pseudomonas hibiscicola RS121 were evaluated for their ability to promote the growth of rice seedlings and produce indole-acetic acid (IAA) and siderophores and to solubilize phosphates. 'Guri' rice seeds were immersed in bacterial endophyte cell suspensions (separated and two-strain mixed), as well as in Escherichia coli DH5α, phosphate-buffered saline (PBS) and water treatments (negative controls). Seeds were sown on agar-water in Petri plates placed vertically at an angle of 65°. The ability of plant growth-promoting endophytic bacteria (PGPEB) to produce IAA and siderophores was determined by Salkowski colorimetric and chrome azurol S (CAS) assays, respectively. Mineral phosphate solubilization activity was calculated by inoculating the endophytes onto medium containing insoluble phosphate. PGPEB showed a positive effect on the growth of rice seedlings, causing a mean growth of shoots and primary-roots of 60 and 67%, respectively. Bacterial strains also showed positive traits for IAA and siderophore production, as well as phosphate-solubilization activity.

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