https://www.alice.cnptia.embrapa.br/alice/handle/item/214 Artigo em periódico indexado (CNPMF) 2026-08-14T04:53:56Z https://www.alice.cnptia.embrapa.br/alice/handle/doc/1189029 Título: Can an HLB-resistant interstock block the long-distance movement of ‘Candidatus Liberibacter asiaticus’ within citrus trees? Autoria: DAROLT, J. C.; RAIOL-JUNIOR, L. L.; CARVALHO, E. V.; ALVES, M. N.; WULFF, N. A.; BAGÉA, J.; GROS, O.; HUFNAGEL, B.; MORILLON, R.; PEÑA, L.; GIRARDI, E. A. Conteúdo: Abstract: Among citrus diseases, Huanglongbing (HLB) is recognized as the most destructive and economically damaging worldwide. It is mainly associated with ‘Candidatus Liberibacter asiaticus’ (CLas) being transmitted by Diaphorina citri. There are no curative treatments or commercial citrus varieties resistant to CLas. Wild Aurantioideae species have been widely screened and, recently, Oceanian genotypes graft- and sexually compatible with Citrus were identified as HLB-resistant; however, there is no information regarding their use as interstocks of commercial varieties yet. Under greenhouse conditions, six HLB-resistant genotypes were evaluated as interstocks between ‘Valencia’ sweet orange scion and ‘Rangpur’ lime rootstock, both susceptible to HLB, with ‘Valencia’ interstock as the control. Rootstocks were nucellar seedlings, and the scion was a commercial accession preimmunized with a mild CTV strain. Plants were assessed for CLas infection and titer in leaves, stem bark, and roots up to 12–24 months after graft-inoculation in the scion and compared to non-inoculated controls. Furthermore, molecular, anatomical, and biometric variables were investigated. As expected, the scion variety was colonized by CLas regardless of the genotype evaluated as interstock. Although bacteria were detected in the roots of most CLas-inoculated plants, CLas movement from the scion to the roots was blocked in 42% and 86% of composite plants when using a F1 hybrid of C. australis × C. inodora or an admixture hybrid of C. glauca, C. australis, and C. australasica as interstocks. Overall, CLas titers were similar in infected plant tissues among the evaluated genotypes, but titers were lower in interstock bark tissues compared to scion and rootstock ones. After one-two years of CLas + CTV infection (experiments I and II, respectively), the dry weight of the root system decreased by 50% in infected trees compared to control trees for most genotypes, and CLas + CTV infection was associated with changes in the sieve phloem and gene expression. These findings suggest that, despite CTV infection, interstocks derived from some hybrids of Australian citrus types have the potential to restrict the movement of CLas from the scion into the roots of infected citrus trees. Long-term evaluation of composite plants in field conditions is necessary to assess tree performance and, ultimately, the impact of CLas blockage by interstocking on HLB disease damage. 2026-01-01T00:00:00Z https://www.alice.cnptia.embrapa.br/alice/handle/doc/1188251 Título: ICTV Virus Taxonomy Profile: Rhabdoviridae 2026 Autoria: WALKER, P. J.; BEJERMAN, N.; BLASDELL, K. R.; DEBAT, H.; DIETZGEN, R. G.; FOOKS, A. R.; ASTUA, J. de F.; GARVER, K.; KONDO, H.; RAMOS-GONZÁLEZ, P. L.; SHI, M.; TESH, R. B.; TORDO, N.; VASILAKIS, N.; WHITFIELD, A. E. Conteúdo: The family Rhabdoviridae comprises viruses with unsegmented, bi-segmented or tri-segmented negative-sense (−) RNA genomes of 10–16 kb. Virions are typically enveloped, with bullet-shaped or bacilliform morphology, but can also be non-enveloped filaments. Rhabdoviruses infect plants or animals, including vertebrates or invertebrates such as arthropods, which can serve as single hosts or act as biological vectors for transmission to animals or plants. Rhabdoviruses include important pathogens of humans, livestock, fish or agricultural crops. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Rhabdoviridae, which is available at ictv.global/report/rhabdoviridae. 2026-01-01T00:00:00Z https://www.alice.cnptia.embrapa.br/alice/handle/doc/1187526 Título: Variabilidade de fosforo, potassio e materia organica no solo em relacao a sistemas de manejo. Autoria: SOUZA, L. D. S.; COGO, N. P.; VIEIRA, S. R. Conteúdo: A variabilidade espacial de fosforo, potassio e materia organica foi avaliada em diferentes solos e sistemas de manejo. Em Elaborado do Sul (RS), o trabalho foi realizado, em agosto de 1990, em um Podzolico Vermelho-Escuro, Kandiudult, amostrando-se os sistemas de prepero convencional, plantio direto, escarificacao e pastagem, na malha de amostragem de 1x1 m e nas profundidades de 0-0,05 e 0,05-0,20 m. Em Passo Fundo (RS), em novembro de 1991, foram amostrados dois tipos de solos: Latossolo Roxo, Hapludox (preparo convencional e plantio direto) e Latossolo Vermelho-Escuro, Hapludox (pastagem), na malha de amostragem de 10x10 m e nas profundidades de 0-0,10, 0,10-0,20 e 0,20-0,30 m Em Passo Fundo, nos sistemas cultivados, foi avaliada tambem a variabilidade da producao de trigo, colhendo-se areas de 1 m, As maiores variabilidades foram encontradas para fosforo e potassio, com seus valores no solo tendendo para uma distribuicao lognormal. Na maioria dos casos, houve correlacao espacial para as propriedades do solo nos sistemas de manejo avaliados, assim como para a producao de trigo. O plantio direto apresentou maiores coeficientes de variacao e menores alcances de dependencia espacial, assumindo-se ter ele determinado maior variabilidade das variaveis analisadas que os demais sistemas; na pastagem, ocorreu a menor veriabilidade do solo. No plantio direto, observou-se, ainda, correlacao esoacial cruzada positiva da producao de trigo com fosforo, com materia organica. 1998-01-01T00:00:00Z https://www.alice.cnptia.embrapa.br/alice/handle/doc/1187401 Título: Traditional and transgenic strategies for controlling tomato-infecting begomoviruses. Autoria: ASTUA, J. de F.; PURCIFULL, D. E.; POLSTON, J. E.; HIEBERT, E. Conteúdo: Viruses of to the family Geminiviridae are considered some of the most important pathogens in tropical and subtropical regions of the world. Members of one Geminiviridae genus, Begomovirus, have been causing severe losses, particularly in tomato (Lycopersicon esculentum) production in the Americas and the Caribbean. Several new begomoviruses have been reported in the region and, at least one, Tomato yellow leaf curl virus (TYLCV), has been brought in from the Old World via infected transplants. In addition, the recombination events that are playing an important role in Begomovirus diversity have increased the complexity of their control. This scenario has led to the search for control measures that go beyond traditional host genetic resistance, chemical controls and cultural practices. In this review, besides the recommended classical control measures, transgenic approaches will be discussed, as well as the mechanisms involved in their successful control of viruses. 2002-01-01T00:00:00Z