Levantamento sorológico de vírus em espécies de cucurbitáceas na região do submédio São Francisco, Brasil

Abstract

Serological survey of virus in cucurbit species in the Lower Middle São Francisco River Basin, BrazilAiming to get information about the virus that most frequently infects cucurbit plants of the species Benincasa hispida, Citrullus spp., Cucurbita spp., Cucumis melo, Lagenaria sp., Momordica charantia and also some F 1 hybrids of C. lanatus with C. lanatus var. citroides in irrigated areas of Petrolina-PE and Juazeiro-BA, experimental and farming areas were surveyed in the first and second half of each year (2005 to 2007). The samples were tested by indirect enzyme-linked immunosorbent assay (ELISA) against antisera specific for Papaya ringspot virus, type watermelon (PRSV), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV) and Cucumber mosaic virus (CMV), and by Agar Double Diffusion against antiserum specific for Squash mosaic virus (SqMV) at the Plant Virus Laboratory of the Federal University of Ceará. Leaf samples from 967 plants were analyzed and 608 of them were infected. Among 125 samples from symptomless plants, 42 allow replication. PRSV-W was predominant, followed by WMV and ZYMV, and mixed infections occurred in all infected species. CMV was detected only in one sample and SqMV was not found. This is an indication that a breeding program for virus resistance in cucurbit species in the region must consider the three potyviruses. Keywords: Citrullus lanatus, Cucumis melo, Serology, Potyvirus, mixed infection.Entre as famílias de plantas utilizadas para a produção de alimentos, as cucurbitáceas ocupam lugar de destaque em importância econômica e social, em particular para o Nordeste brasileiro onde seu cultivo é praticado por pequenos produtores em regime de agricultura familiar. Por outro lado, nessa região, as cucurbitáceas são também exploradas por empresas exportadoras de frutas. Entre as cucurbitáceas de importância econômica para o Nordeste brasileiro destaca-se o melão (Cucumis melo L.), sendo a região a maior produtora nacional, com a produção concentrada nos estados do Rio Grande do Norte e Ceará, a melancia [Citrullus lanatus (Thunb.) Matsum. & Nakai] e as abóboras (Cucurbita spp.), produzidas em toda região. Nessa região, onde as empresas produtoras e exportadoras de frutas utilizam da irrigação, um grande volume dessas e outras cucurbitáceas é produzido por pequenos produtores em condições de sequeiro. Esses cultivos apresentam variabilidade genética para vários caracteres que podem ser utilizadas no melhoramento das culturas. As variedades utilizadas nos cultivos irrigados não foram desenvolvidas 123 Tropical Plant Pathology 34 (2)

Genetic variability of watermelon accessions based on microsatellite markers

“…The Watermelon Germplasm Bank (BGCIA) is a component of the BAGC for northeastern Brazil and has about 870 conserved accessions (Silva et al, 2010) including commercial cultivars, samples from traditional agriculture, and some wild watermelon relatives. Many studies on the use of watermelon genetic resources have utilized accessions preserved in the BGCIA based on morphological descriptions, which have allowed great advances in describing genetic divergence (Queiróz, 1993;Dias et al, 1996;Silveira et al, 2009). …”

Characterization of Cucurbit Production Systems and Disease Prevalence in Municipalities in Pernambuco

“…ZYMV was identified in a significant degree of intensity: it was present in 42.8%, 50% and 78.6% of the infected samples of watermelons; pumpkins and melons, respectively (Table 2). This virus has been identified and reported in various regions of Brazil, e.g., in Maranhão by Moura et al (2001); Roraima by Halfeld-Vieira et al (2004); in the Lower Basin of the São Francisco river by Silveira et al (2009) and more recently by Alencar et al (2012), who confirmed the presence of this virus in 44% of the leaf samples in a survey on cucurbits in the state of Tocantins.…”

“…However, in the State of Pernambuco, only the city of Petrolina was sampled, where the viruses PRSV-W, WMV, ZYMV, CMV and ZLCV were detected. In another work, in the Lower Basin of the São Francisco river, Silveira et al (2009) conducted an extensive collection of cucurbit samples and found that the virus that occurred in greater incidence was PRSV-W, followed by PRSV-P and ZYMV. …”

Susceptibility assessment of watermelon and pumpkin cultivars to potyvirus in Tocantins

“…The location has been associated to the virus predominance, since there are different strains of viruses in each region. Thus, in Brazil, PRSV and ZYMV were predominant in the region of São Francisco valley (SILVEIRA et al, 2009), in the state of São Paulo (REGATIER et al, 2008) and Maranhão state (MOURA et al, 2001). According to Halfeld-Vieira et al (2004), in Roraima, there are PRSV-W, WMV and ZYMV in simple and mixed infections.…”