Root-knot nematodes (RKN) are important plant pathogens affecting rice in South-East Asia and southern Brazil in irrigated rice fields. In order to investigate the specific diversity of RKN associated with irrigated rice in southern Brazil, Meloidogyne spp. from Rio Grande do Sul (RS) and Santa Catarina (SC) States were characterised biochemically by esterase (Est) and malate dehydrogenase (Mdh) phenotypes. Fifty-six Meloidogyne spp. populations were detected in 48% of rice samples, and a total of fiveesterase phenotypes were identified, four of which presented as drawn-out bands in different positions. In RS State, M. graminicola (Est VS1), Meloidogyne sp. 2 (Est R2) and Meloidogyne sp. 3 (Est R3) were identified, which corresponded to ca 80, 40 and 10% of samples, respectively. In SC State, M. graminicola, M. javanica (Est J3), Meloidogyne sp. 1 (Est R1), Meloidogyne sp. 2 and Meloidogyne sp.3 accounted for ca 93.75, 12.50, 62.50, 12.25 and 6.25% of samples, respectively. The esterase phenotypes R1, R2 and R3 are new, never having been detected on rice before. Meloidogyne javanica showed a N1 Mdh phenotype (Rm: 1.0), while four other populations exhibited a N1a (Rm: 1.4) phenotype. All populations were tested with two SCAR markers specific to M. graminicola, which confirmed that, but no specificity was obtained with both markers in relation to the atypical populations analysed. Sequencing and phylogenetic analyses of internal transcribed spacer-rRNA (ITS) were performed to infer the phylogenetic relationship of these atypical Meloidogyne spp. populations. Meloidogyne sp. 1 grouped with the mitotic parthenogenetic species, while the two others (Meloidogyne sp. 2 and sp. 3) clustered with M. graminicola and other meiotic parthenogenetic species. Taken together, these data highlight the unprecedented specific diversity of RKN associated with irrigated rice in southern Brazil. Further morphological and phylogenetic studies involvingthese atypical isolates will be carried out to identify this complex of species
RESUMOQuarenta e quatro populações de Meloidogyne spp. provenientes de amostras de raízes de quivi, coletadas em pomares e viveiros do Estado do Rio Grande do Sul, Brasil, foram caracterizadas bioquimicamente utilizando-se a isoenzima esterase (Est). Meloidogyne arenaria Est A2 (Rm: 1,20, 1,28) foi a espécie mais frequente e ocorreu em 66,65% das amostras. M. ethiopica com fenótipo Est E3 (Rm: 0,92, 1,10, 1,30) foi detectada em 16,66% das amostras, ocorrendo sempre em associação com outras espécies do gênero. Também foram identificadas M. javanica Est J3 (Rm: 1,00, 1,21, 1,35), M. hapla Est H1(Rm: 1,17), M. incognita Est I1 (Rm: 1,03) e Est I2 (Rm: 1,03, 1,10) em 29,9%, 16,66%, 3,33% e 9,79% das amostras, respectivamente. Uma única população atípica de Meloidogyne sp. (3,33%) com o fenótipo Est L3 (Rm: 1,00, 1,10, 1,30) foi detectada, porém nesse caso, não foi possível identificar a espécie com segurança, mesmo quando se recorreu a analise da configuração perineal das fêmeas. Palavras-chave: Actinidia deliciosa, isoenzima esterase, nematoide das galhas. ABSTRACT Survey and characterization of root-knot nematode species in kiwi in Rio Grande do Sul State, BrazilForty-four populations of Meloidogyne spp. obtained from a root-knot nematode survey on kiwi (Actinidia deliciosa) orchards and nurseries in Rio Grande do Sul State were characterized biochemically using esterase isoenzyme (Est). Meloiodgyne arenaria Est A2 (Rm: 1.20, 1.28) was the most frequent species detected in this survey, occurring in 66.65% of the samples. Meloiodgyne ethiopica, with the phenotype E3 (Rm: 0.92, 1.10, 1.30) was detected in 16.66% of the samples in association with other Meloidogyne species. Other species found were M. javanica Est J3 (Rm: 1.00, 1.21, 1.35), M. hapla Est H1 (Rm: 1.17), M. incognita I1 (Rm: 1.03) and I2 (Rm: 1.03, 1.10) identified in 29.9%, 16.66%, 3.33% and 9.79% of the samples, respectively. Only one atypical population presenting the phenotype L3 (Rm: 1.00, 1.10, 1.30) occurred in one orchard (3.33%) but its identification was not possible even through the examination of the perineal patterns of females.
RESUMO -Relata-se a ocorrência de Meloidogyne incognita (Est. i2) em pomar de videira na cidade de Petrolina, Pernambuco. Plantas da cultivar Festival enxertadas sobre 'iAC 766-Campinas', atacadas por Meloidogyne incognita, apresentavam sintomas de menor vigor, folhas amarelecidas e folhagem mais esparsa, e raízes com numerosas galhas em meio ao cultivo de feijão-de-porco (Canavalia ensiformis), também atacado pelo nematoide. Com o objetivo de avaliar a resistência de quatro porta-enxertos tropicais, oito de clima temperado, e as cultivares Niágara Rosada e Chardonnay quanto à reação a M. incognita e M. arenaria, em casa de vegetação, realizou-se este trabalho. Mudas das videiras, mantidas em vaso com solo esterilizado, foram inoculadas com 10.000 ovos + J2 de M. incognita ou M. arenaria por planta. Decorridos oito meses da inoculação, cada planta foi avaliada quanto ao número de galhas e número de ovos por planta, determinandose, a seguir, o fator de reprodução de cada espécie do nematoide (FR=população inicial/população final) nos diferentes materiais testados. Entre os porta-enxertos avaliados, 'Harmony', 'Salt Creek', '1103 Paulsen', 'iAC 572-Jales', 'iAC 313-Tropical', 'K5BB Kober' e 'So4', foram resistentes (FR<1,00) e 'Solferino', imune (FR=0,00) a M. incognita, sendo os demais suscetíveis ao nematoide. Quando se avaliou a reação da videira a M. arenaria, exceto '106-Traviú', '420 A', 'Rupestris du Lot' e '1103 Paulsen', os demais portaenxertos foram resistentes (FR>1,00) ao nematoide. No entanto, ambas as cultivares copa foram suscetíveis às duas espécies de Meloidogyne testadas. Termos para indexação: ocorrência, resistência, nematoide das galhas, Vitis spp. Meloidogyne incognita REPORT ON 'IAC 766-CAMPINAS' ROOTSTOCK IN THE STATE OF PERNAMBUCO AND REACTION OF GRAPE ROOTSTOCKS AND CULTIVARS TO Meloidogyne spp.ABSTRACT -The occurrence of root-knot nematode Meloidogyne incognita (Est. i2) is reported in grapevine in Petrolina municipality, State of Pernambuco. Grape plants of Festival cultivar grafted on the 'iAC 766 -Campinas' rootstock attacked by M. incognita exhibited symptoms of less vigorous growth, yellowing and sparse leaves and multiple galls in the root system in an area cultivated with jack-bean (Canavalia ensiformis) also infected by the same nematode. in order to evaluate resistance of four tropical rootstocks, eight temperate and two cultivars Chardonnay and Niagara Rosada in reaction to M. incognita and M. arenaria, this study was carried out. Seedlings of the investigated grapevine genotypes were maintained in pots with sterilized soil and subsequently inoculated with 10,000 eggs + J2 of M. incognita or M. arenaria per plant in a six replicate design. Eight months after nematode inoculation, each plant was evaluated by counting gall and eggs. The final number of eggs (FP) of each Meloidogyne specie was calculated and the reproductive factor (RF = FP/ iP), determined. Among the tested rootstocks, 'Harmony', 'Salt Creek', '1103 Paulsen', 'iAC 572-Jales', 'iAC 313-Tropical', 'K5BB Kober', 'So...
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