RESUMO
ABSTRACT The aim of this work was to genetically characterize 1,073 isolates of B. thuringiensis, from three Brazilian collections UNESP/Jaboticabal, ESALQ/Piracicaba and EMBRAPA/Sete Lagoas with the main emphasis on the analysis of the cry1 gene types presented by these isolates. To achieve this purpose, oligonucleotide primers were designed based on 16 conserved and 4 unconserved regions of the corresponding sequences from each one of the 16 subclasses of the cry1 set of genes and used in PCR amplification assays. These sequences were amplified and the presence of amplicons for each subclass was evaluated in terms of percentage of gene type per bacterial collection. As a result, 55.7% of the isolates reacted to the primer Gral cry1, and the subclasses cry1Aa, cry1Ab, cry1Ac, cry1Ad, cry1Ae, cry1Af, cry1Ag, cry1Bf, cry1Ca and cry1Fa were detected in high percentages among the isolates ranging from 43.4 to 54.9%. A subclass distribution was observed among the set of isolates from these collections, with the greater percentage of isolates harboring the cry1Ab (42.12%) and the lowest percentage for thecry1Db subclass (0.6%). The genetic variability of the analyzed bacterial collections seems to indicate the ESALQ/Piracicaba and the UNESP/Jaboticabal subsets as sources of promising isolates for the control of Lepidoptera pest insects. For the EMBRAPA/Sete Lagoas subset of isolates, in which the evaluated subclasses frequencies were considered low (below 20%), the cry1B was the most frequently observed gene type present in 38.5% of the isolates.
RESUMO O presente trabalho teve como objetivo caracterizar geneticamente 1.073 isolados de Bacillus thuringiensis, de três coleções brasileiras, provenientes da UNESP, Jaboticabal, da ESALQ/ Piracicaba e da EMBRAPA. Sete Lagoas, analisando os tipos de genes cry1 apresentados pelos isolados. Para isso, foram elaborados oligonucleotídeos iniciadores a partir de 16 regiões conservadas e 4 regiões não conservadas das seqüências de cada uma das 16 subclasses do gene cry1. Essas seqüências foram amplificadas por PCR e a presença de amplicons para cada subclasse foi calculada em porcentagem por gene e por coleção. Nessa análise, 55,7% dos isolados apresentaram amplificação para o gene cry1, e as subclassescry1Aa, cry1Ab, cry1Ac, cry1Ad, cry1Ae, cry1Af, cry1Ag, e cry1Bf, cry1Ca e cry1Fa estão presentes em alta proporção de isolados, variando de 43,4% a 54,9%. Verificou-se que existe uma distribuição das subclasses dentro do banco de isolados de B. thuringiensis em estudo, com maior porcentagem de isolados portadores dos genes cry1Ab (42,12%) e com menor porcentagem de representantes da subclasse cry1Db (0,6%). A variabilidade gênica, nas coleções analisadas, destaca as coleções de Jaboticabal e Piracicaba como fontes de isolados promissores para uso em programas de Controle Biológico de pragas da ordem Lepidoptera. A coleção de Sete Lagoas, na qual as freqüências das subclasses estudadas foram relativamente baixas (abaixo de 20%), destaca somente o gene cry1Ab, presente em 38,5% dos isolados desta coleção.
RESUMO
ABSTRACT Aiming to observe the existence of genetic variability in plants of tropical spiderwort (Commelina benghalensis L.), plants were collected from 10 different regions of 4 Brazilian states (SP, MG, MT and MS). Theseaccessions were analyzed by RAPD molecular markers using 35 arbitrary primers which revealed 84 polymorphic bands. The establishment of 2 main groups with genetic identity above 59% was observed. Theaccessions from Arceburgo and Taiaçú were the ones with greater genetic similarity (95%). The accession from Campo Novo do Parecis was the one with less similarity in terms of the phylogram. The genetic variability observed analyzing the RAPD markers was small among the studied tropical spiderwort accessions, with no relation to the geographic region where the accessions were collected, since the two groups formed involve accessions from different states.
RESUMO Com o objetivo de determinar a existência de variabilidade genética em plantas de trapoeraba (Commelina benghalensis L.), foram coletadas plantas em 10 diferentes regiões de quatro Estados do Brasil (SP, MG, MT e MS). Esses acessos foram submetidos a um estudo de variabilidade genética por meio de RAPD com 35 iniciadores arbitrários, os quais geraram 84 bandas polimórficas. Observou-se a formação de 2 grupos principais e o índice de identidade genética entre os acessos estudados apresentou-se acima de 59%. Os acessos de Arceburgo e Taiaçú foram os que apresentaram a maior similaridade genética (95%). Campo Novo do Parecis foi o acesso que mais se distanciou dentro do filograma. Observou-se que a variabilidade genética pela análise de dados dos marcadores RAPD foi pequena entre os acessos de trapoeraba estudados, a qual não se mostrou relacionada à distribuição geográfica, pois nos 2 grupos existem acessos coletados em diferentes Estados.
RESUMO
Xylella fastidiosa is a xylem-dwelling, insect-transmitted, gamma-proteobacterium that causes diseases in many plants, including grapevine, citrus, periwinkle, almond, oleander, and coffee. X. fastidiosa has an unusually broad host range, has an extensive geographical distribution throughout the American continent, and induces diverse disease phenotypes. Previous molecular analyses indicated three distinct groups of X. fastidiosa isolates that were expected to be genetically divergent. Here we report the genome sequence of X. fastidiosa (Temecula strain), isolated from a naturally infected grapevine with Pierce's disease (PD) in a wine-grape-growing region of California. Comparative analyses with a previously sequenced X. fastidiosa strain responsible for citrus variegated chlorosis (CVC) revealed that 98% of the PD X. fastidiosa Temecula genes are shared with the CVC X. fastidiosa strain 9a5c genes. Furthermore, the average amino acid identity of the open reading frames in the strains is 95.7%. Genomic differences are limited to phage-associated chromosomal rearrangements and deletions that also account for the strain-specific genes present in each genome. Genomic islands, one in each genome, were identified, and their presence in other X. fastidiosa strains was analyzed. We conclude that these two organisms have identical metabolic functions and are likely to use a common set of genes in plant colonization and pathogenesis, permitting convergence of functional genomic strategies.