Marcos Góes Oliveira

Marcadores moleculares RAPD e descritores morfológicos na avaliação da diversidade genética de goiabeiras (Psidium guajava L.)

The knowledge of the genetic and phenotypic variability among different accessions of guava is important for supporting improvement programs of this specie in northern Rio de Janeiro state, which needs new cultivars able to generate income for local farmers. This work aimed to evaluate the genetic divergence among six cultivars and 19 accessions of guava via RAPD molecular markers and morphological characteristics. One hundred and seventeen polymorphic markers were obtained from 28 primers. The results showed a partial agreement between the methods of studied groupings, with the formation of 12 groups. The accessions ‘Vita 3’and ‘6’ were the most divergent, showing genetic distance of 0.663. The comparative analysis of groupings showed that RAPD markers and morphological descriptors were effective in discriminating the accessions and to show potential genetic variability useful in genetic improvement programs.

Involvement of brassinosteroids and ethylene in the control of mitochondrial electron transport chain in postharvest papaya fruit

The plant hormones brassinosteroids (BR) and ethylene (ET) act together to regulate plant metabolism. We used BR and 1-methylcyclopropene (1-MCP, an ET action inhibitor) to elucidate the interactions between both hormones for the regulation of mitochondrial respiratory pathways in papaya fruit. The exogenous application of the 24-epibrassinolide (epiBR) enhanced the alternative oxidase (AOX) capacity. While treatment with Brz2001 (Brz is a specific inhibitor of the BR synthesis) also enhanced AOX capacity, these effects lacked in fruit treated simultaneously with epiBR and Brz. Changing the BR level had no effect on ET emission rate in the first 24 h, but a reduction in ET emission was observed in Brz-treated fruit on the fifth day. Together with Brz, epiBR increased the ET production on the fifth day, following the day in which the treatment was carried out. When the ET sensitivity of fruit was inhibited by the application of 1-MCP, the effects of epiBR and Brz were opposite to those obtained without 1-MCP. AOX capacity was slightly inhibited by epiBR in fruit pre-treated with 1-MCP. Data suggest that BR and ET act antagonistically, therefore regulating, directly or indirectly, AOX capacity during papaya fruit ripening.

RAPD molecular markers and morphological descriptors in the evaluation of genetic diversity of guava (Psidium guajava L.).

The knowledge of the genetic and phenotypic variability among different accessions of guava is important for supporting improvement programs of this specie in northern Rio de Janeiro state, which needs new cultivars able to generate income for local farmers. This work aimed to evaluate the genetic divergence among six cultivars and 19 accessions of guava via RAPD molecular markers and morphological characteristics. One hundred and seventeen polymorphic markers were obtained from 28 primers. The results showed a partial agreement between the methods of studied groupings, with the formation of 12 groups. The accessions ‘Vita 3’and ‘6’ were the most divergent, showing genetic distance of 0.663. The comparative analysis of groupings showed that RAPD markers and morphological descriptors were effective in discriminating the accessions and to show potential genetic variability useful in genetic improvement programs.

Genetic diversity of barbados cherry (Malphigia emarginata D. C.), with RAPD molecular markers and morpho-agronomical characteristics

The knowledge on genetic variability and the relationship among different Barbados cherry accesses is important to maximize the resources for the future genetic breeding. The objective of this work was to determine the genetic variability among 48 accessions of Barbados cherry evaluated using RAPD as DNA markers and morpho-agronomical characteristics. It was used 25 primers, making it possible to obtain 108 markers and to generate 92 different polymorphic products. The obtained markers were of analyzed by the method of Tocher and UPGMA what generated a dendrogram using the Jaccard index. There was a concordance among the studied methods with the formation of 14 groups. The accessions ACE 023 and ACE 033 were the most distinct, presenting a genetic dissimilarity of 0.58. The results allowed to us to conclude that RAPD marker associated with morpho-agronomical characteristics were efficient to discriminate the genetic relationship among the accessions of Barbados cherry and the divergent accessions should be useful in the use of genetic breeding and six of them were recommended for future clonal evaluation as varieties and clonal propagation.

Procedures of Mitochondria Purification and Gene Expression to Study Alternative Respiratory and Uncoupling Pathways in Fruits.

We describe detailed procedures to get intact and well-coupled mitochondria from a variety of fruit species such as papaya (Carica papaya), guava (Psidium guajava), tomato (Solanum lycopersicum), and strawberry (Fragaria x ananassa) as well as the protocols to assess the capacities of AOX and UCP pathways in intact fruit mitochondria. The procedures presented here were tested for the species mentioned above; their use with other types of fruits must be tested for yield of intact and active mitochondria. This is possible from individual adjustments. Strict care during extraction, including the use of osmotic protectants (i.e., mannitol/sucrose) and antioxidants (i.e., cysteine, ascorbate) at defined concentrations, are critical factors to ensure mitochondrial integrity and to obtain higher yields. The mitochondria purified using the discontinuous Percoll gradients described here can be used for the analysis of the capacity of alternative respiration and uncoupling pathways in fruits. In addition, protocols for quantitative and semiquantitative PCR applicable for the analysis of AOX and UCP gene expression in fruits are shown. Microarray and RNA-seq data from public databases are also valuable for the analysis of AOX and UCP genes. In both cases having the sequences of genes or cDNAs to be used in primer design or probe identification is necessary.

Marcadores moleculares RAPD e descritores morfológicos na avaliação da diversidade genética de goiabeiras ( Psidium guajava L.) - doi: 10.4025/actasciagron.v32i4.4720

The knowledge of the genetic and phenotypic variability among different accessions of guava is important for supporting improvement programs of this specie in northern Rio de Janeiro state, which needs new cultivars able to generate income for local farmers. This work aimed to evaluate the genetic divergence among six cultivars and 19 accessions of guava via RAPD molecular markers and morphological characteristics. One hundred and seventeen polymorphic markers were obtained from 28 primers. The results showed a partial agreement between the methods of studied groupings, with the formation of 12 groups. The accessions ‘Vita 3’and ‘6’ were the most divergent, showing genetic distance of 0.663. The comparative analysis of groupings showed that RAPD markers and morphological descriptors were effective in discriminating the accessions and to show potential genetic variability useful in genetic improvement programs.