The beetle Anthonomus grandis Boheman, 1843, is the main cotton pest, causing enormous losses in cotton. The breeding of genetically modified plants with A. grandis resistance is seen as an important control strategy. However, the identification of molecules with high toxicity to this insect remains a challenge. The susceptibility of A. grandis larvae to proteins (Cry1Ba, Cry7Ab, and Mpp23Aa/Xpp37Aa) from Bacillus thuringiensis Berliner, 1915, with toxicity reported against Coleopteran, has been evaluated. The ingestion of different protein concentrations (which were incorporated into an artificial diet) by the larvae was tested in the laboratory, and mortality was evaluated after one week. All Cry proteins tested exhibited higher toxicity than that the untreated artificial diet. These Cry proteins showed similar results to the control Cry1Ac, with low toxicity to A. grandis, since it killed less than 50% of larvae, even at the highest concentration applied (100 μg·g⁻¹). Mpp/Xpp proteins provided the highest toxicity with a 0.18 μg·g⁻¹ value for the 50% lethal concentration. Importantly, this parameter is the lowest ever reported for this insect species tested with B. thuringiensis proteins. This result highlights the potential of Mpp23Aa/Xpp37Aa for the development of a biotechnological tool aiming at the field control of A. grandis.

Plant growth-promoting rhizobacteria (PGPR) can ensure the sustainability of agricultural growth. The objectives of this study were to characterize and determine the effects of Bacillus subtilis, isolate IMA Bs/170005, applied as co-inoculant in the soybean planting furrow. In all treatments, the seeds had been pre-inoculated with Bradyrhizobium japonicum. The experiments were carried out in a greenhouse, and in the field. Different doses of formulated (8.10⁸ spores mL^-1) product with B. subtilis (0; 0.2; 0.4; 0.8; 1.2; 1.6 and 2.0 L ha^-1) were tested. The isolate proved efficient for in vitro auxin production. Under greenhouse conditions, the response to B. subtilis co-inoculation consisted of an increase of up to 26% in length of the root system. In the field, co-inoculation in the furrow proved beneficial for crop growth and yield and can be recommended. The best response rate was 0.4 L ha^-1. At this dose, averaged over 20 and 40 days after sowing and compared to the control with Bradyrhizobium inoculation alone, increases of 5.3% were observed for plant height, 14.8% for shoot fresh weight, 14.1% for shoot dry weight, 8.5% for root dry weight and 6.5% for soybean yield, demonstrating the efficiency of this B. subtilis isolate as a PGPR.

As bactérias solubilizadoras de fosfato (BSF) possuem capacidade para liberar o fósforo (P) que está adsorvido no solo, convertendo fosfato insolúvel em formas solúveis, tornando-o disponível para a absorção pelas plantas. Estas bactérias podem ser encontradas naturalmente no ambiente, tendo o solo como maior reservatório. Além de serem consideradas benéficas e seguras, as BSF representam uma alternativa viável para uso agrícola, pois podem ser multiplicadas e devolvidas à rizosfera (inoculantes, bioestimulantes, biofertilizantes, biopesticidas) para estimular o crescimento das plantas por meio de mecanismos diretos e/ou indiretos. No entanto, encontrar isolados eficientes e adaptados às diversas culturas e sistemas de cultivo permanece um grande desafio. Esta pesquisa teve por objetivo prospectar BSF a partir do solo de diferentes áreas e selecionar, por meio de ensaios in vitro, cepas eficientes e com maior potencial para uso agrícola, bem como, avaliar os efeitos da inoculação em sementes de arroz de terras altas. A partir de amostras de solo coletadas em área conservada do bioma Amazônia, área agrícola produtiva do bioma Cerrado e área degradada com subsolo exposto do bioma Cerrado, foram obtidos 32 isolados solubilizadores. Destes, três foram selecionados pela capacidade de solubilização in vitro para fosfato de cálcio e/ou fosfato de ferro, e com início de solubilização precoce. Identificados como Pantoea sp., Enterobacter sp. e Klebsiella sp., os mesmos não apresentaram danos à sanidade das sementes de arroz, ou à germinação e emergência das plântulas, além de promoverem aumento do comprimento das raízes.

Rice is an important cereal in the basic diet of approximately one-third of the world’s population. The inoculation of seeds with solubilizing bacteria provides a source of P, thereby reducing the need for added inputs to the crop. Soil bacteria with the potential to solubilize phosphates were evaluated in greenhouse and field trials in a 4 × 3 factorial scheme for treatments, with 4 replications. The treatments consisted of a combination of four doses of P (0, 23.3, 46.6, and 70 kg ha?1), based on the use of 0, one-third, two-thirds, and full dose for upland rice, with the inoculation of three isolates of phosphate-solubilizing bacteria (AAC01 – Pantoea sp.; AAC02 – Enterobacter sp.; and AAC04 – Klebsiella sp.). In the greenhouse experiment, AAC02, together with a dose of 46.6 kg ha?1 of P, increased soil basal respiration (SBR) and shoot fresh mass. AAC01 increased soil basal respiration linearly up to 70 kg ha?1 of P and increased root fresh mass by 46.6 kg ha?1. In the field experiment, the P doses increased the P content of rice grains, roots, shoot dry mass, and plant height. AAC04 associated with 46.6 kg ha?1 provided equivalent levels of P in the soil and leaves, and P levels in the grains were higher than those in non-inoculated plants fertilized with 70 kg ha?1 of P. The AAC04 treatment yielded significant gains in both greenhouse and field experiments, with an approximately 33% reduction in phosphate fertilization, resulting in a greater number of panicles per square meter and full grains per panicle. Based on these findings, we recommend AAC04 as a biofertilizer to ensure environmentally healthier rice production in the future.