Plant viral diseases constitute a major contributor to agricultural production losses, significantly impacting the economies of exporting countries by more than USD 30 billion annually. Understanding and researching the biology and genomics of viruses is crucial for developing virus-resistant genetically edited or genetically modified plants. Genetic modifications can be targeted to specific regions within genes of target plants which are important or essential for the virus to establish a systemic infection, thus fostering resistance or enabling plants to effectively respond to invading agents while preserving their yield. This review provides an overview of viral incidence and diversity in tropical fruit crops and aims to examine the current state of the knowledge on recent research efforts aimed at reducing or eliminating the damage caused by viral diseases, with emphasis on genetically edited products that have reached the market in recent years.

The aim of this work was to investigate the ability of Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) of cucurbits, to colonize melon tissues. Under greenhouse conditions leaves and seeds were inoculated with a spontaneous mutant of A. citrulli (group I) resistant to rifampicin (Ac1Rif), and samples of hypocotyls, cotyledonary leaves, roots, leaves and stems were processed at three-day intervals. When the 1st pair of melon leaves had been inoculated, A. citrulli was only detected until the 10th pair of leaves (1.3 x 10³ CFU g-1 of leaf) and the consecutive stem (3.3 x 10³ CFU g-1 of stem) on the 30th day. However, after seed inoculation A. citrulli colonized the hypocotyl, roots, cotyledonary leaves, leaves and stems and was only detected until the 4th pair of leaves (1.62 x 10² CFU g-1 of leaf) and the consecutive stem (9.1 x 10¹ CFU g-1 of stem) on the 24th day post-inoculation. In conclusion, A. citrulli colonized different parts of the melon plant over time, depending on its initial location, leaves or seed. This confirms what has been observed in the field, that expanded leaves and stems are the main inoculum sources for melon blossoms and fruit, therefore providing scientific bases for developing more effective strategies for BFB management. Este trabalho investigou a habilidade de Acidovorax citrulli, agente causal da mancha-aquosa em cucurbitáceas, colonizar plantas de meloeiro. Em condições de casa de vegetação, folhas e sementes foram inoculadas com um mutante espontâneo de A. citrulli (grupo I) resistente a rifampicina (Ac1Rif) e a intervalos de três dias, amostras de hipocótilo, folhas cotiledonares, raízes, folhas ou ramos foram processadas. Após a inoculação no 1º par de folhas, A. citrulli foi detectada até o 10º par de folhas (1,3 x 10³ UFC g-1 de folha) e no ramo consecutivo (3,3 x 10³ UFC g-1 de ramo) aos 30 dias. A partir da inoculação das sementes A. citrulli colonizou efetivamente o hipocótilo, raízes, folhas cotiledonares, folhas e ramos, sendo a bactéria detectada até o 4º par de folhas (1,62 x 10² UFC g-1 de folha) e no ramo consecutivo (9,1 x 10¹ UFC g-1 e ramo) aos 24 dias após a inoculação. Pode-se concluir que A. citrulli colonizou diferentes partes do meloeiro ao longo do tempo, dependendo da localização do inóculo inicial, folhas ou sementes. Isto confirma o que tem sido observado nas condições de campo, ou seja, que folhas expandidas e ramos são fontes de inóculo para flores e frutos de melão, dando, portanto, suporte científico para o desenvolvimento de estratégias mais efetivas de manejo da mancha-aquosa do meloeiro

Guava decline is a complex disease resulting from the parasitism by Meloidogyne enterolobii (Me), which predisposes the plant to root rot caused by Fusarium sp. Three in vitro experiments were carried out with the aim of: (i) selecting the Fluensulfone dosage capable of causing Me mortality; (ii) verifying the effect of Fluensulfone on Pochonia chlamydosporia and Trichoderma harzianum; (iii) evaluating the effect of Pochonia chlamydosporia and Trichoderma harzianum in pure doses and in association with Fluensulfone on Me mortality. Fluensulfone at 2 L.ha-1 had no effect on fungi. The associated and pure doses of treatments had a significant effect on Me mortality. A field experiment was also carried out in a guava orchard where decline occurred. The following treatments were tested: Fluensulfone; P. chlamydosporia; P. chlamydosporia + Fluensulfone; T. harzianum; T. harzianum + Fluensulfone; Carbofuran, and control. All treatments reduced Me population, since relative efficiency was higher than 80%. Fluensulfone used alone or in combination with biological nematicides provided an increase in guava productivity. Maintaining Me population low in the field is an important option for increasing productivity and reducing the losses suffered by farmers.

O fósforo (P) desempenha um papel essencial no crescimento e produtividade das culturas. Tradicionalmente, a carência de P no solo foi mitigada por meio da aplicação de fertilizantes fosfatados. Contudo, sabe-se que a dinâmica do nutriente no solo é complexa, especialmente devido aos processos de adsorção, que reduzem significativamente a eficiência de adubação fosfatada, assim como a disponibilidade desse nutriente para as plantas. Nesse contexto, a aplicação de microrganismos especializados na solubilização de fosfato emerge como uma estratégia promissora para aprimorar a disponibilidade desse nutriente. Essa abordagem não apenas reduz a dependência de fertilizantes químicos, mas também contribui para sistemas agrícolas mais sustentáveis, atenuando os riscos ambientais associados. Esta revisão se concentra nos benefícios dos microrganismos solubilizadores de fosfato (MSPs), seus mecanismos subjacentes e suas contribuições para aplicações agrícolas. Os MSPs representam uma ferramenta biotecnológica de extrema importância para aumentar a produtividade agrícola, oferecendo uma ampla variedade de aplicações potenciais.

Stem canker of coffee (SCC) is caused by Fusarium solani, F. decemcellulare, and F. lateritium, which induces symptoms such as cankers, wilting, yellowing, and dieback of plagiotropic and orthotropic twigs, leading to the death of the coffee plants. The absence of a standardized inoculation method to assess the disease hampers the development and implementation of effective strategies to manage and mitigate the impact of SCC. This study evaluated the efficacy of three inoculation methods in inducing SCC, and it was carried out in both laboratory and greenhouse conditions. The conidial inoculation on leaf disks (CILD) method involved applying a spore suspension (1 × 10⁶ spores ml⁻¹) of F. solani, F. decemcellulare, and F. lateritium to foliar disks from young and fully expanded leaves. The mycelial inoculation in injured stems (MIIS) method utilized the mycelial plug of F. solani, which was inserted in longitudinal cuts of clones LB1 and CV02 seedlings. In the root immersion conidial inoculation (RICI) method, seedling roots of clones LB1 and CV02 were cut 1 cm above the root cap and immersed in a spore suspension of F. solani (1 × 10⁶ spores ml⁻¹). Each treatment was evaluated daily for disease symptoms and signs of F. solani. The CILD approach proved to be an excellent time-saving tool in this investigation, and MIIS the most efficient to induce SCC symptoms. After 8 to 11 postinoculation days, wilting, yellowing, necrosis in the inoculated region, cankers, and signs of F. solani were observed on studied clones. The RICI method induced yellowing only 180 days after inoculation.