, Márcia Vanusa da Silva RESUMOA diversidade genética de catorze cultivares de cana-de-açúcar (Saccharum oficinarum) foi acessada por meio de marcadores moleculares ISSR. Objetivou-se caracterizar molecularmente as cultivares estudadas. Foram utilizados trinta e sete primers de ISSR, dos quais, oito foram eficientes na amplificação do DNA das amostras analisadas, sendo sete primers suficientes para distinguir todas as cultivares de cana-de-açúcar envolvidas nas análises. A faixa de amplicons variou de 300 a 2000 pb. As cultivares RB 92579 e RB 863129 apresentaram maiores coeficientes de similaridade (77%) enquanto as cultivares RB 961 e RB 931611 formaram o grupo com menor similaridade (22%). Os resultados indicam que os marcadores ISSR foram úteis na análise da diversidade genética e geração de padrões genéticos (fingerprint), em germoplasma de cana-de-açúcar. Marcadores ISSR cultivar-específico foram obtidos com o primer UBC 817 para as 14 cultivares testadas. Num próximo trabalho, mais primers ISSR serão utilizados para buscar mais polimorfismos dessas e de outras cultivares de cana-de-açúcar. Termos para indexação:Saccharum oficinarum, marcadores moleculares ISSR, diversidade genética. ABSTRACTGenetic diversity of fourteen sugarcane cultivars was accessed by ISSR molecular markers. With the aim to characterizing and validating the efficiency of these markers in the fingerprint of studied cultivars, thirty seven ISSR primers were used, from which, eight were efficient for the DNA amplification. Seven primers were efficient to discriminate the fourteen studied sugarcane cultivars. The amplicons varied from 300 to 2000 bp. The cultivars RB 92579 and RB 863129 presented higher similarity coefficient (77%) while the cultivars RB 961 and RB 93611 formed the group with lower similarity (22%). The results suggested that ISSR markers were useful in the analysis of the genetic diversity and in the fingerprint in sugarcane germosplasm. In the next step more ISSR primers will be used in order to obtain more polymorphism from these varieties and to analyze more sugarcane cultivars.Index terms: Saccharum oficinarum, molecular markers, genetic diversity. A cana-de-açúcar (Saccharum officinarum) é uma cultura de grande importância econômica para alguns países da América, especialmente para o Brasil. O agronegócio da cana-de-açúcar, que reúne 6% dos empregos agroindustriais brasileiros, é responsável por 35% do PIB do estado de São Paulo, maior produtor do país, e 10% do PIB de Pernambuco, segundo maior produtor do Nordeste (SINDAÇÚCAR, 2005). Assim, a atividade canavieira do Brasil é responsável por cerca de um milhão de empregos diretos, o que destaca o seu potencial socioeconômico.A busca constante de novas cultivares através do melhoramento genético tem possibilitado a seleção de genótipos mais promissores e adaptados às diversas condições edafoclimáticas do país (SIMÕES NETO et al.,
Spondias tuberosa Arruda (umbuzeiro), a Brazilian semiarid plant, is a species of great economic, social, and ecological importance. In folk medicine, the leaves have been used in the treatment of diabetes, inflammation, stomach and uterine pains, and constipation. In this study, the antioxidant properties of ethyl acetate and methanol leaves extracts were evaluated in vitro using different methods: free radicals elimination by DPPH and ABTS assays, and transition metal reduction by phosphomolybdenium assay. In addition, a phytochemical study was also carried out. The methanolic leaves extracts showed the strongest antioxidant activity and the higher values for total phenolic and flavonoids. The results showed that S. tuberosa leaves have antioxidant activity and this seems to be related to the phenolic content.
ABSTRACT. Fusarium wilt caused by Fusarium oxysporum f. sp lycopersici (Fol) is one of the main diseases affecting tomatoes. The BHRS 2,3 genotype of tomato is, however, resistant to this disease. A proteomic approach was used to understand the defense mechanisms of this genotype using the tomato root, the first tissue that interacts with the fungus, as a target. Protein was extracted and separated by two-dimensional electrophoresis followed by staining with Coomassie brilliant blue. The proteins were identified by MALDI-TOF/TOF mass spectrometry. A total of 22 proteins were identified, 21 of which showed differential expression with 12 proteins being upregulated and nine being downregulated. Plants responded to the pathogen with increased expression of pathogenesis-related proteins. We noted the induction of proteins involved in hypersensitivity reaction and other defense mechanisms. The expression of proteins of primary metabolism related to energy production, however, decreased, as did the expression of two proteins related to defense against abiotic stress. These results demonstrate the presence of important mechanisms for defense against Fol in the tomato genotype BHRS 2,3.
Chitinases are important component of plant defence in response to attack by pathogens. To identify specific chitinase, we constructed a cDNA library using total RNA from a genotype-resistant tomato inoculated with conidia of isolates race 2 of Fusarium oxysporum f.sp. lycopersici (Fol). One chitinase (SolChi) clone was isolated and sequence analysis shows that the cDNA clone SolChi encodes an acidic isoform of class III chitinase. Southern blotting indicated that SolChi was present only once in the tomato genome. Real-time quantitative RT-PCR assay show that the expression of this gene is induced upon infection with Fol, and the accumulation of transcripts for this R protein was rapid in the resistant genotype during the first 24 h. A putative role for chitinase in tomato is defence against fungal pathogens.
Cowpea crops have the highest social and economic relevance to Brazil, being the food base of families mainly in the semi-arid areas of the country. Charcoal rot caused by Macrophomina phaseolina is an economically important disease of cowpea that can cause significant reductions in bean yield. This study aimed to access the genetic diversity of M. phaseolina isolates obtained from cowpea grown in the Pernambuco semi-arid region, by molecular analysis. Fifty-one isolates, collected from municipality of Belém do São Francisco from cowpea plants and displaying typical symptoms and signs of charcoal rot, were studied using inter-simple sequence repeat (ISSR) markers. Unweighted pair-group method using arithmetic means (UPGMA) clustering of data showed that isolates clearly differentiate into two groups. The group 1 comprises the majority of isolates and the group 2 contains two isolates, isol46 and isol47. The highest similarity index (0.9) was observed between the isolates isol22 and isol35 and the lowest similarity index (0.2) was observed between isol37 and isol46 isolates. Our results revealed that the ISSR-PCR fingerprinting patterns were useful for differentiating M. phaseolina isolates from V. unguiculata plants sampled. Therefore, genetic characterization of this fungus is of importance for the effective disease management.
Endophytic bacteria may influence agricultural production in several ways, including promoting plant growth. Two experiments were conducted in order to evaluate the combination of endophytic bacteria from the Brazilian Northeast region aims at the commercial introduction of the inoculation of these bacteria in micropropagated sugarcane plants using a temporary immersion bioreactor. One experiment was done in tubes with sterile commercial substrate, and the other was done in pots with soil; both were installed in a greenhouse. A mixed inoculation was performed in six inoculated endophytic diazotrophic bacteria in micropropagated sugarcane plants, variety RB92579. In the experiment with soil, the mixed inoculation significantly increased the shoot dry matter of plants without the addition of nitrogen fertilizer. However, the accumulation of total-N in the tissues showed no significant differences between treatments with and without nitrogen fertilization. The evaluation of micropropagated seedlings showed no increases in the parameters tested. The results showed that the response of inoculation in temporary immersion bioreactor micropropagation is possible, and that the application of homologous strains may have contributed to a better response by the interaction of endophytic bacteria with sugarcane RB92579. Further studies should be conducted to improve the methodology, which indicates a great potential to optimize this process on a commercial scale.
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