Roots of Zinnia elegans exhibiting galls were observed and collected in the city of Pacoti, CE, Brazil. Through the morphological characterization and molecular analysis of the ITS and 28S rDNA regions, the causal agent was identified as a nematode of the genus Meloidogyne species M. javanica. This is the first detection of M. javanica in Zinnia elegans in the state of Ceará in Brazil.
Roots of plants characteristic of the Brazilian caatinga showing necrosis symptoms were observed in Iguatu, CE, Brazil. To identify the species, morphological characterization was performed, through the morphometry of females, and molecular analysis of the ITS and 28S rDNA regions. The nematodes Pratylenchus zeae and P. brachyurus were identified as causal agents, confirming pathogenicity by Koch postulates. This is the first report of P. zeae and P. brachyurus in caaatinga plants in the state of Ceará, Brazil.
During a survey in 2018 for plant nematodes associated with roots and soil in cactus cultivation areas in Ceará State (3°44'48"S, 38°34'29"W), cysts were found on roots of mandacaru, Cereus jamacaru DC. This cactus is native to Brazil, can grow to 6-10 meters in height, and is widely distributed in the Northeast region (Romeiro-Brito et al. 2016) where it is used in construction, in disease remedies, as forage, and as an ornamental (Sales et al. 2014). Several cysts, second-stage juveniles (J2) and eggs extracted from the soil and roots, using sucrose centrifugation, were examined by scanning electron microscopy (SEM) and light microscopy (LM) to determine morphological and morphometric characteristics. Molecular characteristics were determined by DNA extraction from J2 and embryonated eggs using a protocol specific for Heteroderidae (Subbotin et al., 2018). The internal transcribed spacer sequence (ITS) region of the rDNA and D2-D3 regions of the 28S rDNA were amplified using the universal primers TW81 (5′-GTTTCCGTAGGTGAACCTGC-3′) and AB28 (5′-ATATGCTTAAGTTCAGCGGGT-3′), D2A(5′-ACAAGTACCGTGAGGGAAAGTTG-3′) and D3B(5′-TCGGAAGGAACCAGCTACTA-3′), respectively. To confirm that mandacaru is a host for C. cacti, six plantlets of mandacaru were inoculated with 1,800 eggs of the nematode, and kept in a greenhouse at 31 ± 3 ºC and irrigated daily. Six non inoculated mandacaru plantlets served as control treatment. Morphometric characteristics of cysts (n=35) were body length, excluding neck, 555.8 ± 87.8 (354,9 - 727,6) μm, body width 392.1 ± 63.4 (297.9 - 553.7) μm, neck length 63.5 ± 25.8 (49.8-105.0) μm, length to width ratio 1.4 ± 0.2 (1.0-1.8) μm and vulval cone length 48.4 ± 15.2 (40.7 –53.6) μm. Cysts had a rough surface, were lemon-shaped to rounded and had a zigzag cuticular pattern with a protruding vulval cone. They were circumfenestrate without underbridge and bullae, but with the presence of vulval denticles. Measurements of second-stage juveniles (n = 13) included the body length 511.2 ± 33.7 (452.7 - 551.5) μm, stylet length 28.0 ± 2.8 (25.4 - 34.0) μm, tail length 50.7 ± 5.1 (40.6 - 57.4) μm, tail hyaline region 22.7 ± 2.2 (18.9 – 27.1), with a = 20.9 ± 2.2 (17.7-24.3) μm, b = 5.4 ± 0.4 (5.1-5.8) μm, b'= 3.4 ± 0.4 (3.1-3.9) μm, c = 10.2 ± 1.3 (8.9-13.3) μm and c' = 3.8 ± 0.4 (3.0-4.5) μm. The observations of essential morphological characteristics for identification indicated that the species found on C. jamacaru was Cactodera cacti (Filipjev & Schuurmans-Stekhoven, 1941) Krall & Krall, 1978. The sequences of the studied rDNA regions were submitted to GenBank (ITS: MW562829 and D2–D3 regions of 28S: MW562830). The samples used for molecular analysis showed a high degree of sequence identity (99.59%) with C. cacti, from China, Iran and USA for the ITS region. The identity of the D2-D3 regions of 28S sequence was 99.54% with C. cacti isolates from Germany and 99.41% with isolates from USA. Phylogenetic analyses were performed using Maximum likelihood (ML) method for both individual loci, confirming the species as Cactodera cacti. All inoculated mandacaru plantlets showed C. cacti cysts on the roots after 60 days, confirming that mandacaru is a host for C. cacti. This species was reported in São Paulo State, in 2001, associated with ornamental cactus cultivated in pots, but plant species were not identified (Santos et al., 2001). The second report in Brazil was to Schlumbergera sp., an ornamental plant (Oliveira et al. 2007). In both studies, the nematode was not morphologically nor molecularly characterized. Cactodera cacti has been commonly associated with cactus worldwide (Esser, 1992). It has been reported in association with C. jamacaru was first reported in 2011 in China (Duan et al. 2012). This is the first report of the occurrence of C. cacti on C. jamacaru in field conditions in Brazil, and its presence in cactus cultivation areas with agricultural importance represents a threat to cactus production in the country.
Weed reaction to parasitism by the guava root-knot nematode, Meloidogyne enterolobiiReação de plantas daninhas ao parasitismo pelo nematoide das galhas da goiabeira, Meloidogyne enterolobii MOTA, Erika Araújo (1) ; SOUZA JUNIOR, Francisco Jorge Carlos (2) ; SANTOS, Carmem Dolores Gonzaga (3)
<p>O tomateiro (<em>Solanum lycopersicum</em> L.) é uma das olerícolas mais cultivadas no mundo. Há diversas doenças que afetam a cultura, destacam-se fitonematoides do gênero <em>Meloidogyne</em>. O presente trabalho teve como objetivo realizar avaliação do efeito da influência da temperatura e exsudatos radiculares de tomate 'Santa Clara' e <em>Datura metel</em> na eclosão de juvenis de <em>M. javanica</em> raça 1 e na infestação de mudas de tomateiro. Todas as análises foram realizadas no Laboratório de Fitopatologia da Universidade Federal do Ceará, no período de outubro de 2018 a janeiro de 2019. Como resultados, foram observados que os exsudatos radiculares do tomateiro foram os que mais favoreceram a eclosão dos juvenis, a temperatura influencia diretamente a infectividade. <em>D. metel</em> mesmo sendo considerada uma má hospedeira, seus exsudatos radiculares não afetam a capacidade de parasitismo de <em>M. javanica </em>raça 1.</p>
<p>A fruticultura é uma importante atividade agrícola para o estado do Ceará, principalmente nas exportações, o que gera um aumento na participação na balança comercial cearense. As exportações de frutas frescas do Ceará em 2019 movimentaram mais de U$ 62 milhões, com produção de 1.319.140 toneladas, em uma área de 371.900 hectares. Entre as frutas cultivadas no Ceará, destaca-se o cultivo de uva, sendo o estado o quarto maior produtor da região Nordeste. Um dos principais entraves à viticultura são as doenças, pois provocam perdas na produtividade. Visto que o estado do Ceará é considerado área com presença de <em>Xanthomonas campestri </em>pv<em>. viticola</em>, que é uma praga quarentenária, o objetivo deste estudo foi avaliar a situação e as ações fitossanitárias na sanidade vegetal relacionadas a essa praga no estado. Foi observado que há uma política fitossanitária estadual de combate à praga quarentenária bem detalhada, além de uma estrutura montada para executar as ações de gestão das pragas pela Agência de Defesa Agropecuária do Ceará (ADAGRI). O programa estadual de prevenção, controle e erradicação do cancro bacteriano da videira do estado do Ceará foi eficiente para reduzir a ocorrência de <em>Xanthomonas campestri</em> pv. <em>viticola</em> em áreas de cultivo de <em>Vitis</em> spp.</p>
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