Edição dos resumos do 45º Congresso Nacional de Genética, Gramado, 1999

CARNEIRO, N. P.

GAMA, E. E. G.

GUIMARAES, C. T.

LOPES, M. A.

MEIRELLES, W. F.

PACHECO, C. A.

PAIVA, E.

PARENTONI, S. N.

SANTOS, M. X.

SOUZA, I. R. P.

VASCONCELOS, M. J. V.

Repository Open Access to Scientific Information from Embrapa

06.02 - GENÉTICA MOLECULAR VEGETAL06.02-021 CARACTERIZAÇÃO DE ESPÉCIES DA SECÇÁO EXTRANERVOSAEDO GÊNERo ARACHIS. Vrcente Euge-nio de Rosa Jwúor', José Francisco Montenegro ValIs2,Catalina Romero Lopesl, Claudio Costa', 'Dep. Defesa Fitossanitária,FCA/UNESP, C.P.237, Botucatu-SP, CEP 18603-970, 2CENARGEN{EMBRAPA. Brasília-DF, 3Dep.Genética, ffi/UNESP,Botucatu, SP. vicente@surfnet.com.br ..o gênero Arachis L. (Legurninosae) é tipicamente sul-americano, com espécies distribuídas por vários estados brasilei-ros, além de Bolívia, Paraguai, Argentina e Uruguai, e têm como principal representante A. hypogaea. O gênero édividido em 9 secções taxonômicas baseadas em morfologia, distribuição geográfica e compatibilidade. A secçãoExtranervosae é de ocorrência exclusiva do território brasileiro e é composta até o momento, de nove espécies, além deuma nova espécie anteriormente classificada como A. aff pietrarellii, porém com diversas características morfológicascontrastantes. Para se estabelecer as relações de afinidade nesta secção, foram analisados acessos de A. villosulicarpa; A.burchelli, A. lutescens, A. macedoi, A. pietrarellii, A. prostrata, A. recusa, A..setinervosa; e da espécie nova. O germoplasmafoi proveniente do Banco de Gennoplasma de Arachis do Centro Nacional de Pesquisa de Recursos Genéticos eBiotecnologia{Empresa Brasileira de Pesquisa Agropecuária (CENARGEN/EMBRAPA, Brasília, DF). Folhas jovensforam utilizadas para a extração de DNA e posterior amplificação por RAPD. Dos 80 "primers" testados, 13 apresenta-ram polimorflsmo evidente, gerando 66 bandas polimórficas, as quais foram avaliadas como caracteres binários porpresença e ausência. O grau de similaridade genética utilizou coeficientes de similaridade e de distância taxonômica emprograma NTSYS utilizando-se algorítmo UPGMA. Os fenogramas obtidos pelas análises de agrupamento revelaramalta similaridade entre os acessos de cada espécie, sendo facilitada a classificação de alguns acessos. Entre os acessos deA. villosulicarpa não houve detecção de variabilidade genética e a espécie nova pôde ser comprovada pela diferenciação. dos outros agrupamentos formados. Órgão Financiador: CNPq06.02-022 SINGLE STRAND BINDING PROTEIN ENHANCES lHE PROCESSIVITY OFlHE DEOXYNUCLEOTIDYLlRANSFERASE ACI1VTIY PROMOTED BYTIIE TIlll PROTEIN FROMArabidop.m thaliana. Luche D.D.J.Godoi P.H.Cz.Oliva G.z.Menck CF.M.!. 1- Instituto de Ciências Biomédicasll, USP; 2- Instituto de Física, USP-SC e-mail: ddluche@usp.brThe Thil gene product from Arabidopsis thaliana participares in the biosynthesis of thiamin in organels and aIso presentscharacteristics related to repair/toIerance of damaged DNA, as it complements bacteria (Escherichia colí) deficiency ineither base or nucleotide excision repair pathways. The aminoacid sequence of this protein shows homology to certaindomains of prokaryotic DNA polymerases and, in fact, previous results showed that it complements bacteria deficient inDNA Polymerase I. ln vitro experiments of DNA polymerization, using purified preparations of this protein, indicatethat THII has the ability to incorporate deoxynucleotides into acid insolubIe products, both in the presence and absenceof a DNA template, that are sensitive to DNAse L Therefore, the THII protein has an activity of deoxynucleotidyltransferase. To conflnn that tbis activity is directly promoted by THII proteín, and not by a contaminating enzyme, weperfonned the imunoprecipitation of the pratein preparation using anti-TIllI antibody. This complex showed a strongreduction in the deoxynucleotidyl transferase activity, pointing to the fact that it is really a TIllI property. Single strandbinding protein (SSB), a known important eomponent for DNA polimerization, was tested on TIllI activity. The dataindicate that SSB enhances its pracessivity, resuIting in the polimerization of DNA products of bigher molecuIar weight,either for the presence ar absence of template. This might be an important feature for the TInI repair/tolerance of ON Adamaged related aetivity and it is a strong evidence that TRII, and related homoIogous proteins, perfonn a role in themaintenance of organellar genomes. Financial support: FAPESP, PADCf-CNPq06.02-023 SSR MARKERS AS POWERFUL TOOLS FàRMAIZE ELITE GERMPLASM FINGERPRINTING. Guimarães,CT.; Souza. I.R.P.; Parentoni. S.N.; Carneiro. N.P.; t Gama. E.E.G.; Pacheco. CA.; Meirelles, w.F.; Vasconcelos,M.J.V.; Lopes, M.A.; Paiva. E. EmbrapaMilhoe Sorgo, CP.15t Sete Lagoas,MG 35701-970 claudia@cnpms.embrapa.brSimple sequence repeats (SSRs) or mierosatellites is a class of genetic markers consisting of short nucleotide sequence./ motifs tandemly repeated and evenIy distributed throughout eukaryotic genomes. SSRs show bigh levels of polymorpbismsand provide a codorninant marker system based on PCR technique. Due to the availability of high amount of SSR Ioeiwell mapped on maize genome (www.agron.missouri.edu'ssr.htm/i.this marker ean be widely used in genetic fingerprintingand erap protection. ln addition, SSR technology presents the potential advantage of reliability, reproducibility anddiscrimination. The goal of tbis work was to characterize and to follow the genetic identity of maize elite inbred lines used in288GENÉTICA MOLECULAR VEGETAL - 06.02the current Embrapa Maize and Sorghum breeding program and to develop a genetic profile for the commercial bybrids. Forthis purpose, we screened 230 SSR primer pairs (Research Genetics, Ine.) in order to choose those that generate goodamplification patterns. Selected primers were used to amplify genomic DNA of22 maize inbred lines and 24 hybrids derivedfrom those inbred lines, including commercial ones. PCR products were resolved in 8% non-denaturing polyacrylamide gelsstained with ethidium bromide. Gel images were captured by the Eagle-Eye System and the size of each allele was estimatedusing the RFLPscan Gel Analysis Software 2.1 with 100 bp ladder as size standard. Polymorphic index contents (pIC) wereestimated for each SSR locus. PIC value measures the discriminatory eower of a SSR locus, considering the number and therelative frequency of the expressed alleles. PCR patterns were also used to evaluate genetic distances among maize eliteinbred lines. Genetic distance matrix was used to construct dendrograms using the UPGMA method. Maize elite genotypeswere characterized by 74 easily scorable SSRs loci, generating a genetic profile of Embrapa 's rnaize elite germplasm, Thisstudy indicates that SSRs may be the optimum approach for the identification and characterization of maize genotypes,compared to other methods currently available. The tropical maize SSR profiles can be readily applied for measuring andmonitoring genetic diversity, forsupporting Intellectual Propeny Protection and for future strategies in molecu1ar breeding.This work was supported by grants from PRONEX, CNPq, and SEP/EMBRAPA.06.02-024 NON MENDEUAN SEGRAGATION IN TRANSGENIC PLANTS. Romano E.. Rodrigues K.. Proite K.Monte D.,Aragão F. EMBRAPA-CENARGEN, romano@cenargen.embrapa.br.IGenes transformed ínto plants are usually inherited in a regular Mendelian fashion. However, several reports havedescribed transformants in which the transgenes fails to segregate in a simple Mendelian pattem. We have generatedhundreds of transgenics beans and soybeans by the biolistic technique. About 10% of the transgenic plants do nottransmitted the exogenous genes to the progeny or transmitted in a ratio not expected by Mendelian manner. In thisstudy, we analyzed two non mendelian transgenic lines: I) The transgenic bean line 158, obtained by transformation withpMD4 vector containing the gene block Rep- TrAP-REn, from the bean golden mosaic virus (BGMV) genome in antisenseorientation and the gus gene. This plant is immune to BGMV and the progeny showed complete absence of the intro-duced DNA. Il) The transgenic soybean liue 33-3 obtained with pAGl vector, containing the ahas genes that co.ifersresistance against the herbicide imazapyr. Self-pollination of this plant showed a deficiency of transgenic plants (10AHASs: 1 AHASR). In subsequent generations, the segregation ratio stabilized at 1 AHASs: 1 AHASR .The number ofseeds per silique was reduced by 50% in this line. Such exceptional segregations ratios could result from a variety ofmechanisms. The complete absence of the introduced DNA in 158 line progeny could be result of normal segregationfrom a chimeric plant or by disruption of genes during the plasmid integration in the transformation processo To addressthis question, rnicrogametophyte gus analysis was performed. This assay showed the normal ratio expected for onetransgenic locus, (1 gus' : 1 gus-). Thus, we concluded that the distorted segregation observed is not a consequence froma chimeric transgenic plant and probably caused by disruption of genes related with gametogenesis and/or embryogen-esis. In order to isolate these genes, we have been using the plasrnid rescue approach. Three clones were obtained fromeach plant. Sequencing analysis of these clones revealed new open reading frames probably related with the non mendelianphenotype. Our results suggests that 158 and 33-3 lines contain plasmid-insertions that delete or disrupt genes relatedwith gametophytic growth and/or development. The next step in this study will be the transformarion of bean andsoybean with antisense versions of the isolated ORFs obtained in this work.06.02-025 USO DE MARCADORES MOLECULARES RFLPE AFLP NO ESTUDO DA DIVERSIDADE GENÉTICA DODENDEZEIRO (Elaeis guineensis Jacq. e E. oleifera (Kunth) Cortés). E. Barcelos; R. N. V.da Cunha; B. Nouye N. R. Sousa.Embrapa Amazônia Ocidental/Manaus - barcelos@cpaa.embrapa.brA Embrapa Amazônia Ocidental dispõe de uma ampla coleção de germoplasma de dendezeiro, compreendendo 296acessos da espécie africana E. guineensis e 182 acessos da espécie americana E. oleifera, ocupando um total de 48hectares de área experimental. A correta caracterização e avaliação da coleção é de grande importância para gestão e usoeficiente do recurso genético conservado, entretanto caracterizar coleções de espécies perenes com base em descritoresmorfológicos e agronômicos representa um trabalho longo e oneroso, além de problemas como baixa capacidade dediscriminação interpopulacional para o caso do dendezeiro. Com o objetivo de estudar a estrutura e o nível de variabili-dade genética presente na coleção, empregaram-se marcadores moleculares RFLP e AFLP como ferramentas. RFLP foideterminado pela utilização de 37 sondas cDNA em amostras representando uma ampla cobertura da área de ocorrência289

SSR markers as powerful tools for maize elite germplasm fingerprinting.

SSR markers as powerful tools for maize elite germplasm fingerprinting.

Abstract

Similar works

Full text

Available Versions

Repository Open Access to Scientific Information from Embrapa