RESUMOMeloidogyne mayaguensis foi detectado pela primeira vez no estado de Goiás, em duas propriedades (Formosa e Luziânia), causando dano em pomares comerciais de goiaba (Psidium guajava) cv. Paluma de um ano de idade e de 14 anos, respectivamente. Plantas infectadas pelo nematóide mostraram redução de crescimento, clorose generalizada, deficiência nutricional e redução qualitativa e quantitativa de produção. As raízes severamente infestadas apresentaram-se pouco desenvolvidas e deformadas pela presença de múltiplas galhas de tamanho variado. Mamoeiros (Carica papaya) cv. Formosa, plantados em consórcio com as goiabeiras na propriedade de Formosa, apresentaram numerosas galhas no sistema radicular, embora, nenhum sintoma secundário de meloidoginose tenha sido observado na parte aérea. A produção de frutos dos mamoeiros foi alta, evidenciando tolerância dessa cultivar ao nematóide. O fenótipo M2 para a isoenzima esterase (Rm: 0,7, 0,9) foi detectado e M. mayaguensis identificado em ambas as culturas e propriedades. As análises com marcadores moleculares espécie-específica usando primers que amplificam regiões intergênicas do DNA ribossomal e do DNA mitocondrial também confirmaram esse diagnóstico. Levantamento realizado, em outras localidades da fazenda em Formosa mostrou a presença de Meloidogyne javanica em baixa população, corroborando a idéia de introdução de M. mayaguensis na área, através do plantio de mudas infectadas, oriundas da região de Petrolina. Na propriedade em Luziânia, o nematóide é provavelmente de ocorrência natural, considerando-se a idade das plantas e o número reduzido de goiabeiras infectadas. Palavras-chave: fenótipo de esterase, DNA ribossômico, DNA mitocondrial, identificação, nematóide das galhas. ABSTRACT Detection of Meloidogyne mayaguensis on guava and papaya in Goiás State of Brazil using molecular markersMeloidogyne mayaguensis was reported for the first time in the State of Goiás (Formosa and Luziânia), causing damage in oneyear old and 14 year-old commercial guava (Psidium guajava) cv. Paluma orchards. Plants infected by the nematode showed symptoms such as stunted growth, general chlorosis, nutrient deficiency and consequent decline in yield quality and quantity. Severely infested root systems were poorly developed, distorted by small and large multiple galls and devoid of fine roots. Plants of papaya cv. Formosa were cultivated in consortium with guava in the Formosa orchard and presented several galls in the root system, but no root-knot-nematode root-knot-nematode secondary symptoms were observed in the aerial part. The production of papaya fruits was high, evidencing tolerance of this cultivar to the symptoms were observed in the aerial part. The production of papaya fruits was high, evidencing tolerance of this cultivar to the were observed in the aerial part. The production of papaya fruits was high, evidencing tolerance of this cultivar to the nematode. The M2 phenotype (Rm: 0.7, 0.9) was detected for the isoenzyme esterase and M. mayaguensis was identified in both crops...

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Este é o primeiro assinalamento de Pratylenchus brachyurus em meloeiro (Cucumis melo) ocorrendo em condições naturais de campo no Brasil, no Pólo Açu-Mossoró, RN. São apresentados dados morfométricos da população encontrada.

The biogenesis of root-knot nematode (Meloidogyne spp.)-induced galls requires the hyperactivation of the cell cycle with controlled balance of mitotic and endocycle programs to keep its homeostasis. To better understand gall functioning and to develop new control strategies for this pest, it is essential to find out how the plant host cell cycle programs are responding and integrated during the nematode-induced gall formation. This work investigated the spatial localization of a number of gene transcripts involved in the pre-replication complex during DNA replication in galls and report their akin colocation with the cell cycle S-phase regulator Armadillo BTB Arabidopsis Protein 1 (ABAP1). ABAP1 is a negative regulator of pre-replication complex controlling DNA replication of genes involved in control of cell division and proliferation; therefore, its function has been investigated during gall ontogenesis. Functional analysis was performed upon ABAP1 knockdown and overexpression in Arabidopsis thaliana. We detected ABAP1 promoter activity and localized ABAP1 protein in galls during development, and its overexpression displayed significantly reduced gall sizes containing atypical giant cells. Profuse ABAP1 expression also impaired gall induction and hindered nematode reproduction. Remarkably, ABAP1 knockdown likewise negatively affected gall and nematode development, suggesting its involvement in the feeding site homeostasis. Microscopy analysis of cleared and nuclei-stained whole galls revealed that ABAP1 accumulation resulted in aberrant giant cells displaying interconnected nuclei filled with enlarged heterochromatic regions. Also, imbalanced ABAP1 expression caused changes in expression patterns of genes involved in the cell division control as demonstrated by qRT-PCR. CDT1a, CDT1b, CDKA;1, and CYCB1;1 mRNA levels were significantly increased in galls upon ABAP1 overexpression, possibly contributing to the structural changes in galls during nematode infection. Overall, data obtained in galls reinforced the role of ABAP1 controlling DNA replication and mitosis and, consequently, cell proliferation. ABAP1 expression might likely take part of a highly ordered mechanism balancing of cell cycle control to prevent gall expansion. ABAP1 expression might prevent galls to further expand, limiting excessive mitotic activity. Our data strongly suggest that ABAP1 as a unique plant gene is an essential component for cell cycle regulation throughout gall development during nematode infection and is required for feeding site homeostasis.