Agriculture and livestock integration is a sustainable practice that improves both crop yield and pasture recuperation/formation. However, to achieve success it is important to identify crop cultivars more adapted to intercropping with grasses. Th erefore, the objective was to evaluate nutrient concentration and grain yield of soybean [Glycine max (L.) Merr.] cultivars with diff erent life cycles as aff ected by palisadegrass [Brachiaria brizantha (Hochst. ex A. Rich) Stapf] intercropped in the same furrow at diff erent depths, in a no-till system, as well as dry matter production and protein concentration of palisadegrass pasture. Experiments were performed during two growing seasons, on a Typic Haplorthox, at Botucatu, São Paulo State, Brazil. Th e experimental design was a randomized block, arranged in a 2 × 4 factorial scheme, with six replications. Treatments consisted of two cropping systems (sole cropped soybean; soybean and palisadegrass intercropped) and four soybean cultivars (super-early cycle [Monsoy 6101], early cycle [Embrapa 48], normal cycle [BRS 133], and late cycle [Emgopa 313]). Life cycle duration of the soybean had a marked eff ect, and only early cycle soybean were successful intercrops. Intercropping palisadegrass with super-early or early soybean cultivars were viable options to crop-livestock integration, because they did not aff ect both soybean or palisadegrass yield. In addition, with these cultivars, it was possible to cultivate grain and then aft erward more time for cattle (Bos taurus and Bos indicus) grazing in the same area, providing greater revenue compared to sole soybean cropped or in the intercropping with longer cycle cultivars.

Intercropping corn (Zea mays L.) with forages, such as palisadegrass {Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster [syn. Brachiaria brizantha (Hochst. ex A. Rich.) Stapf]} or guineagrass [Megathyrsus maximus (Jacq.) B. K. Simon & S. W. L. Jacobs (syn. Panicum maximum Jacq.)], provides large amounts of biomass for use as straw in no‐tillage systems or as pasture. However, it is important to evaluate what time these forages have to be sown into corn systems to avoid reductions in both corn and forage production. This study, conducted for three growing seasons at Botucatu, Brazil, evaluated nutrient concentration and yield of corn as affected by time of forage intercropped as well as forage's dry matter production. Our data showed that intercropping systems did not reduce leaf nutrient concentrations and grain yield of corn in relation to sole corn. The simultaneous intercropping of corn and guineagrass resulted in the lowest plant population (51,200 plant ha−1), number of ears per plant (1.0), and, consequently, the lowest corn grain yield (9801 kg ha−1). Guineagrass seeded at the time of corn fertilizer topdressing resulted in the highest plant population (59,400 plants ha−1), number of ears per plant (1.2), and corn grain yield (12,077 kg ha−1). Forage production was highest when intercrop was done simultaneously. Palisadegrass could be intercropped with corn both simultaneously or at topdressing fertilization stage. In contrast, it is recommended that guineagrass should only be intercropped with corn at topdressing fertilization.

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In tropical regions with dry winters, low plant biomass accumulation during the period between spring–summer crop cultivations can negatively impact soil resources and make the no‐till (NT) system unsustainable. Incorporating palisadegrass [Urochloa brizantha (Hochst. Ex A. Rich.) R.D. Webster] [syn. Brachiaria brizantha (Hochst. Ex A. Rich) Stapf] in traditional grain production areas could improve soil quality for subsequent crops and lead to positive effects on grain yield. The objective of this study was to evaluate the effects of growing palisadegrass on soil fertility, plant nutrition, and grain yield of subsequent cash crops in a tropical region. The experiment was performed in southeastern Brazil in plots that were grown for two consecutive growing seasons (2002–2003 and 2003–2004) with either monocropped corn (Zea mays L.) or corn intercropped with palisadegrass. An initial evaluation of soil fertility was performed in November 2004 when the land was either fallow (following monocropped corn) or covered by palisadegrass (intercropped areas). After the preceding treatments, the following crops were cultivated: soybean [Glycine max (L.) Merr.] during the 2004–2005 and 2005–2006 spring–summer, white oat (Avena sativa L.) during the 2005 and 2006 fall–winter, and corn during the 2006–2007 spring–summer. Intercropping palisadegrass with corn increased the soil fertility compared to monocropped corn. Soybean, white oat, and corn all had higher leaf macronutrient concentrations and grain yields in previously intercropped areas than in monocropped areas. Therefore, the periodic, short‐term incorporation of a perennial forage grass, such as palisadegrass, as a cover crop is recommended to increase grain production and to improve the soil fertility of grain‐production areas.

Phytopathogenic bacteria affect a wide range of crops worldwide and have a negative impact in agriculture due to their associated economic losses and environmental impacts. Together with other biotic and abiotic stress factors, they pose a threat to global food production. Therefore, understanding bacterial survival strategies is an essential step toward the development of new strategies to control plant diseases. One mechanism used by bacteria to survive under stress conditions is the formation of persister cells. Persisters are a small fraction of phenotypic variants within an isogenic population that exhibits multidrug tolerance without undergoing genetic changes. They are dormant cells that survive treatment with antimicrobials by inactivating the metabolic functions that are disrupted by these compounds. They are thus responsible for the recalcitrance of many human diseases, and in the same way, they are thought to contribute to the survival of bacterial phytopathogens under a range of stresses they face in the environment. It is believed that persister cells of bacterial phytopathogens may lead to the reoccurrence of disease by recovering growth and recolonizing the host plant after the end of stress. However, compared to human pathogens, little is known about persister cells in phytopathogens, especially about their genetic regulation. In this review, we describe the overall knowledge on persister cells and their regulation in bacterial phytopathogens, focusing on their ability to survive stress conditions, to recover from dormancy and to maintain virulence.

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Intercropping of maize (Zea mays L.) with perennial forage, such as palisade grass [Brachiaria brizantha (Hochst. ex A. Rich) Stapf], provides large amounts of biomass that can be used as straw for no-tillage systems or as pasture for animal grazing. In addition, the use of narrow row spacing may increase maize grain yield. However, it is important to evaluate intercrops at different row spacing to avoid reductions in both maize and forage biomass production. The objectives of this field experiment during two growing seasons in Brazil were as follows: (1) to evaluate the influence of intercropping and row spacing on maize yield, leaf nutrient concentration, and plant population and development; and (2) to assess the influence of row spacing on palisade grass herbage mass and leaf nutrient concentration. The experimental design was a randomised complete block design in a 2 × 2 factorial scheme, with eight replications. The treatments comprised two row spacing distances (0.45 and 0.90 m) and two crop management types (maize monoculture and intercropped with palisade grass). The nutrient concentrations in the leaves of the maize plants were in the ideal range for this crop under all conditions studied. Plant height, height of first ear, and number of grains per ear were higher with the narrow row spacing. Maize grain yield was similar in both crop management types (10 301 and 9745 kg ha–1 for monoculture maize and intercropped, respectively). However, maize grain yield at the narrow row spacing was higher than that obtained with the wide row spacing (9948 v. 8905 kg ha–1). In contrast, row spacing did not affect the nutrient level or quality (crude protein concentration) of palisade grass. The amount of dry matter (DM) from palisade grass was lower at maize harvesting (4.7 Mg ha–1) and 90 days after harvesting (6.9 Mg ha–1) under narrow spacing. However, the amount of DM was similar at both row spacings at 120 days after maize harvesting (9.2 Mg ha–1). When there is no problem with water and nutrient availability, the use of maize and palisade grass intercropping under both row spacing conditions (0.45 and 0.90 m) provides an option for the production of forage DM without reducing the maize grain yield.

Xanthomonas citri ssp. citri (Xac) is the causal agent of citrus canker, an economically important disease that affects citrus worldwide. To initiate the characterization of essential biological processes of Xac, we constructed integrative plasmids for the ectopic expression of green fluorescent protein (GFP)-labeled proteins within this bacterium. Here, we show that the disruption of the alpha-amylase gene (amy), the site of plasmid integration into the bacterial chromosome, does not alter its pathogenesis while abolishing completely the ability of Xac to degrade starch. Furthermore, our GFP expression system was used to characterize ORF XAC3408, a hypothetical protein encoded by Xac that shares significant homology to the FtsZ-stabilizing factor ZapA from Bacillus subtilis (ZapA(Bsu)). GFP-XAC3408 expressed in Xac exhibited a septal localization pattern typical of GFP-ZapA(Bsu), which indicates that XAC3408 is the Xac orthologue of the cell division protein ZapA(Bsu). The results demonstrate the potential of GFP labeling for protein functional characterizations in Xac, and, in addition, the Xac mutant strain labeled at the septum constitutes a biological model for the exploration of antibacterial compounds able to inhibit cell division in this plant pathogen.