Utilização de marcadores microssatélites para avaliação da diversidade genética de variedades locais de mandioca

A mandioca é cultivada pelos agricultores familiares que conservam em suas propriedades variedades locais, atuando como mantenedores desse importante recurso genético. A diversidade genética existente para a espécie pode ser estimada por meio de marcadores moleculares microssatélites. Assim, objetivou-se realizar a caracterização molecular de quatro variedades locais de mandioca (Cacau Branca, Cacau Roxa, Cacau Amarela e Mandioca Pão) cultivadas por agricultores familiares no município de Apiacás-MT, utilizando marcadores microssatélites. Foram amostradas quatro variedades locais de mandioca, totalizando 40 indivíduos. O material foliar foi utilizado para a extração do DNA total e para as amplificações via PCR (Polymerase Chain Reaction). Foram amplificados 67 alelos, sendo que os loci que amplificaram o maior e o menor número de alelos, foram SSRY126 e SSRY21, respectivamente. Dentre os alelos amplificados foram identificados 33 alelos raros (49%). Os valores médios de heterozigosidade observada (0,840) foram superiores aos valores de heterozigosidade esperada (0,643), refletindo em índices de fixação negativos. Dentre os loci testados, os que apresentaram valores de PIC acima de 0,5 foram: GA12; GA131; GA140; SSRY27; SSRY28; SSRY126. O dendrograma formado pelo método de agrupamento hierárquico UPGMA gerou cinco grupos genéticos que estão em concordância com a análise bayesiana. Sendo assim, foi observado que há diversidade genética entre as variedades locais cultivadas por agricultores familiares do município de Apiacás. Os indivíduos AP5 (Cacau Branca) e AP20 (Cacau Roxa) são os mais divergentes geneticamente entre o conjunto analisado e a variedade Mandioca pão está mais distante geneticamente das outras três variedades (Cacau Branca, Cacau Roxa, Cacau Amarela)

Genetic Diversity and Population Structure of Zingiber officinale Roscoe in Northern Mato Grosso State, Brazil

The ginger (Zingiber officinale Roscoe) was introduced in Brazil in the 16th century and is currently cultivated for commercial purposes and for own consumption, in urban and rural backyards. Although the species reproduces vegetatively, the exchange of rhizomes among gardeners contributes to the maintenance of the genetic variability of the species, since they carry out the selection of genotypes adapted to the soil and climate conditions of the cultivation areas. Studies on the variability of ginger cultivated in Brazil are scarce, therefore  this study aimed to evaluate the genetic diversity and population structure, using ISSR molecular markers, of 245 ginger specimens cultivated in rural and urban backyards of twenty municipalities (populations) in the state of Mato Grosso, Brazil. The ISSR primer set used was classified as moderately informative and it amplified a  total of 105 fragments, of which 97.60% showed polymorphism, indicating the existence of genetic variability. The genetic diversity assessment separated the 245 specimens into 30 hierarchical groups. Group 1 was the most representative (72%), containing specimens from all populations sampled. The population-level assessment allocated 18 populations in a single group, while the populations of Apiacás and Peixoto de Azevedo formed exclusive groups. The Molecular Variance Analysis revealed that the genetic variation found within populations (76.58%) is greater than that found among populations (23.42%), which indicates a process of fixing of alleles and genetic structuring. The Bayesian analysis identified only two distinct genetic groups and some populations sampled showed a predominance of one of the groups, which evidences the process of genetic structuring. According to the genetic distance of Nei (h) and the Shannon Index (I), Apiacás was the population that presented the greatest genetic diversity, while Matupá was characterized as the population with less diversity. The genetic diversity found indicates that the cultivation, handling and selection performed by gardeners, as well as the exchange of rhizomes for propagation, are important factors for the conservation of the genetic diversity of the species. We also concluded that backyards are a source of genetic resources for programs that aim to identify traits of interest and promote the cultivation of the species in Brazil

AVALIAÇÃO DE MARCADORES ISSR PARA ESTUDOS MOLECULARES DE BACUPARI

The species Garcinia brasiliensis has various scientifically proven applications in folk medicine, however, the lack of dissemination of these characteristics of the species is a current problem. Among the studies that can enhance this knowledge is the genetic diversity study, for which the use of ISSR molecular markers is recommended for being reliable, rapid, and economical. Therefore, this study aimed to select and classify dominant molecular markers for studies with the G. brasiliensis species. For this, total DNA was extracted from 40 bacupari individuals. Two individuals were selected to perform ISSR primer amplification tests via PCR. 31 primers were tested, which were classified regarding their amplification quality as good, poor, or absent. Out of the 31 tested primers, 13 showed good results regarding the presence and quality of the bands, therefore, they were indicated for use in research aiming the molecular characterization and evaluation of genetic diversity of the species Garcinia brasiliensis.A espécie Garcinia brasiliensis apresenta diversas aplicações na medicina popular comprovadas cientificamente, entretanto, a falta de divulgação sobre essas características da espécie é um problema atual. Dentre os estudos que podem alavancar esse conhecimento está o da diversidade genética, para isso, o uso de marcadores moleculares ISSR é indicado por serem confiáveis, rápidos e econômicos. Sendo assim, este trabalho teve como objetivo selecionar e classificar marcadores moleculares dominantes para estudos com a espécie G. brasiliensis. Para isso, foi extraído o DNA total de 40 indivíduos de bacupari, dos quais foram selecionados dois, que apresentassem bandas bem definidas e sem arraste, para realizar testes de amplificação de primers ISSR via PCR. Ao todo, foram testados 31 primers, os quais foram classificados quanto sua qualidade de amplificação, utilizando os padrões bom, ruim e ausente. Dos 31 primers testados, 13 apresentaram bons resultados quanto à presença e qualidade das bandas, portanto, indicados para o uso em pesquisas que visem à caracterização molecular e avaliação da diversidade genética da espécie Garcinia brasiliensis. Palavras-chave: Garcinia brasiliensis; marcador molecular; Pantanal.   Evaluation of ISSR markers for molecular studies of bacupari   ABSTRACT: The species Garcinia brasiliensis has various scientifically proven applications in folk medicine, however, the lack of dissemination of these species characteristics is a current problem. Among the studies that can enhance this knowledge is genetic diversity, for which ISSR molecular markers application is recommended as it is reliable, rapid, and economical. Therefore, this study aimed to select and classify dominant molecular markers for G. brasiliensis research. For this, total DNA was extracted from 40 bacupari individuals. Two individuals were selected to perform ISSR primer amplification tests by PCR. 31 primers were tested, which classified their amplification quality as good, poor, or absent. Out of the 31 tested primers, 13 showed good results regarding the presence and band quality, therefore, they were indicated for research use, aiming molecular characterization and Garcinia brasiliensis genetic diversity evaluation. Keywords: Garcinia brasiliensis; molecular marker; Pantanal