RESUMO
The search for more environmental friendly herbicides, aiming at the control of agricultural pests, combinated with less harmfulness to human health and the environment has grown. An alternative used by researchers is the application of products of secondary plant metabolism, which are investigated due to their potential bioactivities. Thus, species belonging to the Myrtaceae family are potential in these studies, since this family is recognized for having high biological activity. A species belonging to this genus is Psidium cattleyanum, which has a medicinal effect and its fruits are used in human food. Thus, the objective of this research was to evaluate and compare the phyto-cyto-genotoxicity of aqueous and ethanolic leaf extracts of the specie P. cattleyanum, from plant bioassays, as well as to identify the main classes of compounds present in the extracts. For this, the extracts were prepared, characterized and biological tests were carried out by evaluating, in seeds and seedlings of lettuce and sorghum, the variables: percentage of germination, germination speed index, root growth and aerial growth; and in meristematic lettuce cells the variables: mitotic phases, mitotic index, nuclear alterations and chromosomal alterations. Flavones, flavonones, flavonols, flavononols, flavonoids, alkaloids, resins, xanthones and anthraquinone glycoside were characterized in the ethanolic extract. Both evaluated extracts, in the highest concentration, inhibited the initial plant development. All treatments caused alterations in the mitotic phases and inhibited mitotic index. In addition, the treatments promoted an increase in nuclear and chromosomal alterations. The mechanism of action presented was aneugenic, clastogenic and determined in epigenetic alterations. The ethanolic extract was more cytotoxic, since it had a more expressive effect at a lower concentration. Despite the cytotoxicity of the extracts under study, they promoted alterations at lower levels than the glyphosate positive control.
A busca por herbicidas mais amigáveis ââao meio ambiente, visando o controle de pragas agrícolas, aliado a uma menor nocividade à saúde humana e ao meio ambiente tem crescido. Uma alternativa utilizada pelos pesquisadores é a aplicação de produtos do metabolismo secundário de plantas, que são investigados em virtude do seu potencial bioativo. Assim, espécies pertencentes à família Myrtaceae são potenciais nestes estudos, uma vez que esta família é reconhecida por possuir alta atividade biológica. Uma espécie pertencente a este gênero é Psidium cattleyanum, que possui efeito medicinal e seus frutos são utilizados na alimentação humana. Assim, o objetivo desta pesquisa foi avaliar e comparar a fitocitogenotoxicidade de extratos foliares aquosos e etanólicos da espécie P. cattleyanum, a partir de bioensaios vegetais, bem como identificar as principais classes de compostos presentes nos extratos. Para isso, os extratos foram preparados e caracterizados e foram realizados testes biológicos avaliando, em sementes e plântulas de alface e sorgo, as variáveis: porcentagem de germinação, índice de velocidade de germinação, crescimento radicular e crescimento aéreo; em células meristemáticas de alface foram avaliadas as variáveis: fases mitóticas, índice mitótico, alterações nucleares e alterações cromossômicas. Flavonas, flavononas, flavonóis, flavononóis, flavonóides, alcalóides, resinas, xantonas e glicosídeo de antraquinona foram caracterizados no extrato etanólico. Ambos os extratos avaliados, na maior concentração, inibiram o desenvolvimento inicial da planta. Todos os tratamentos causaram alterações nas fases mitóticas e inibiram o índice mitótico. Além disso, os tratamentos promoveram aumento de alterações nucleares e cromossômicas. O mecanismo de ação apresentado foi aneugênico, clastogênico e epigenético. O extrato etanólico foi mais citotóxico, pois teve efeito mais expressivo em menor concentração. Apesar da citotoxicidade dos extratos em estudo, eles promoveram alterações em níveis inferiores ao controle positivo glifosato.
Assuntos
Controle de Pragas , Pragas da Agricultura , Myrtaceae , Citogenética , GenotoxicidadeRESUMO
Polyploidy, a numerical alteration of the karyotype, is one of the most important mechanisms in plant speciation and diversification, but could also be detected among populations, the cytotypes. For example, Psidium cattleyanum, a polyploid complex, has chromosome numbers ranging from 2n=3x=33 to 2n=12x=132. Polyploidization causes an increase in DNA content, and both modifications may cause alteration in plant growth, physiology, and epigenetics. Based on this possibility, here we aim to verify the influence of the polyploidization on the production of P. cattleyanum essential oil chemotypes. Differences in the DNA contents, as a proxy to different ploidies, were observed and three distinct chemotypes were identified through the chromatographic profile analysis. The Psidium cattleyanum DNA content and qualitative and quantitative characteristics of the essential oils presented a positive relationship. Plants with higher DNA contents presented higher levels of oil production, which was mostly composed of hydrogenated sesquiterpenes, while plants with lower DNA contents produced lower amount of oil, which was mostly composed of hydrogenated monoterpenes. Based on the importance of essential oils, polyploid plants, which present higher DNA content, are recommended as possible matrices for the propagation of new plants with the potential to produce major compounds of agronomic and pharmacological interest.
Assuntos
Óleos Voláteis , Psidium , Sesquiterpenos , DNA , Monoterpenos , Óleos Voláteis/química , Poliploidia , Psidium/químicaRESUMO
The search for more environmental friendly herbicides, aiming at the control of agricultural pests, combinated with less harmfulness to human health and the environment has grown. An alternative used by researchers is the application of products of secondary plant metabolism, which are investigated due to their potential bioactivities. Thus, species belonging to the Myrtaceae family are potential in these studies, since this family is recognized for having high biological activity. A species belonging to this genus is Psidium cattleyanum, which has a medicinal effect and its fruits are used in human food. Thus, the objective of this research was to evaluate and compare the phyto-cyto-genotoxicity of aqueous and ethanolic leaf extracts of the specie P. cattleyanum, from plant bioassays, as well as to identify the main classes of compounds present in the extracts. For this, the extracts were prepared, characterized and biological tests were carried out by evaluating, in seeds and seedlings of lettuce and sorghum, the variables: percentage of germination, germination speed index, root growth and aerial growth; and in meristematic lettuce cells the variables: mitotic phases, mitotic index, nuclear alterations and chromosomal alterations. Flavones, flavonones, flavonols, flavononols, flavonoids, alkaloids, resins, xanthones and anthraquinone glycoside were characterized in the ethanolic extract. Both evaluated extracts, in the highest concentration, inhibited the initial plant development. All treatments caused alterations in the mitotic phases and inhibited mitotic index. In addition, the treatments promoted an increase in nuclear and chromosomal alterations. The mechanism of action presented was aneugenic, clastogenic and determined in epigenetic alterations. The ethanolic extract was more cytotoxic, since it had a more expressive effect at a lower concentration. Despite the cytotoxicity of the extracts under study, they promoted alterations at lower levels than the glyphosate positive control.
Assuntos
Alcaloides , Psidium , Bioensaio , Análise Citogenética , Humanos , Extratos Vegetais/toxicidade , Folhas de PlantaRESUMO
Polyploidy, a numerical alteration of the karyotype, is one of the most important mechanisms in plant speciation and diversification, but could also be detected among populations, the cytotypes. For example, Psidium cattleyanum, a polyploid complex, has chromosome numbers ranging from 2n=3x=33 to 2n=12x=132. Polyploidization causes an increase in DNA content, and both modifications may cause alteration in plant growth, physiology, and epigenetics. Based on this possibility, here we aim to verify the influence of the polyploidization on the production of P. cattleyanum essential oil chemotypes. Differences in the DNA contents, as a proxy to different ploidies, were observed and three distinct chemotypes were identified through the chromatographic profile analysis. The Psidium cattleyanum DNA content and qualitative and quantitative characteristics of the essential oils presented a positive relationship. Plants with higher DNA contents presented higher levels of oil production, which was mostly composed of hydrogenated sesquiterpenes, while plants with lower DNA contents produced lower amount of oil, which was mostly composed of hydrogenated monoterpenes. Based on the importance of essential oils, polyploid plants, which present higher DNA content, are recommended as possible matrices for the propagation of new plants with the potential to produce major compounds of agronomic and pharmacological interest.
A poliploidia, uma alteração numérica do cariótipo, é um dos mecanismos mais importantes na especiação e diversificação das plantas, mas também pode ser detectada entre populações, os citótipos. Por exemplo, Psidium cattleyanum, um complexo poliplóide, tem números de cromossomos que variam de 2n=3x=33 a 2n=12x=132. A poliploidização causa um aumento no conteúdo de DNA, e ambas as modificações podem alterar o crescimento, a fisiologia e a epigenética da planta. Com base nessa possibilidade, objetivamos verificar a influência da poliploidização na produção de quimiotipos de óleo essencial de P. cattleyanum. Diferenças nos conteúdos de DNA, representando diferentes ploidias, foram observadas e três quimiotipos distintos foram identificados através da análise do perfil cromatográfico. O conteúdo de DNA de Psidium cattleyanum e as características qualitativas e quantitativas dos óleos essenciais apresentaram correlação positiva. Plantas com maiores conteúdos de DNA apresentaram maiores rendimentos na produção de óleo, que era majoritariamente composto por sesquiterpenos hidrogenados, enquanto plantas com menores conteúdos de DNA produziram menores quantidade de óleo, que era majoritariamente composto por monoterpenos hidrogenados. Com base na importância dos óleos essenciais, plantas poliplóides, que apresentam maiores conteúdos de DNA, são recomendadas como possíveis matrizes para a propagação de novas plantas com potencial para produzir compostos importantes de interesse agronômico e farmacológico.
Assuntos
DNA , Óleos Voláteis , PsidiumRESUMO
Guava (Psidium guajava L.) crop is severely affected by the nematode Meloidogyne enterolobii. Native Psidium species have been reported as sources of resistance against this nematode. Knowledge on the molecular relationship between Psidium species based on plant resistance gene analogs (RGA) can be useful in the genetic breeding of guava for resistance to M. enterolobii. In this study, RGA markers from conserved domains, and structural features of plant R genes, were employed to characterize Psidium species and establish genetic proximity, with a focus on nematode resistance. SSR markers were also applied owing to their neutral nature, thus differing from RGA markers. For this, species reported as sources of resistance to M. enterolobii, such as P. cattleianum and P. friedrichsthalianum, as well as species occurring in the Atlantic Rainforest and susceptible genotypes, were investigated. In 10 evaluated Psidium species, high interspecific genetic variability was verified through RGA and SSR markers, with intraspecific variation in P. guajava higher with SSR, as was expected. Resistant species were clustered by RGA markers, and differential amplicons among genotypes resistant and susceptible to M. enterolobii were identified. Knowledge on the molecular relationships between Psidium species constitutes useful information for breeding of the guava tree, providing direction for hybridization and material for rootstocks. Additionally, the genetic relationship between native species, which have been little studied, and P. guajava were estimated by RGAs, which were confirmed as important markers for genetic diversity related to pathogen resistance.
Assuntos
Resistência à Doença , Doenças das Plantas/parasitologia , Proteínas de Plantas/genética , Psidium/classificação , Tylenchoidea/patogenicidade , Animais , Sequência de Bases , Sequência Conservada , Evolução Molecular , Marcadores Genéticos/genética , Variação Genética , Genótipo , Repetições de Microssatélites , Filogenia , Doenças das Plantas/genética , Psidium/genética , Psidium/parasitologiaRESUMO
Nematodes are important pests of soybean throughout the world and cause high yield losses. As a control strategy, the identification of resistance genes is an important aim of breeding studies. Plants possess resistance genes (R), which are responsible for the recognition of pathogens and activation of the defense system. R genes and resistance gene analogs (RGAs) possess conserved domains, from which nucleotide-binding site is the most common. Using degenerate primers originating from these domains, it is possible to identify and isolate sequences of R and RGA genes. In this study, soybean genotypes resistant to the nematodes Heterodera glycines, Meloidogyne incognita, M. javanica, and M. enterolobii were compared by the use of RGAs and simple sequence repeat (SSR) markers. Forty-six soybean genotypes were studied, including plant introductions (PIs), commercial crops, and source of resistance genotypes. Thirteen combinations of RGA primers and different SSRs linked to QTLs were used to confirm resistance to soybean cyst nematodes (SCN). Fragments associated with resistance to the studied nematodes were amplified in the source of resistance and PI genotypes. RGA markers were efficient at distinguishing groups of genotypes that were resistant and susceptible to Meloidogyne spp and SCN. Combinations of specific primers were identified through their ability to amplify nucleotide sequences from possible resistance candidate genes. SSR markers contributed to the analysis of SCN race specificity, showing that the QTLs identified by these markers are distinct from those identified by RGA markers.
Assuntos
Genes de Plantas , Glycine max/genética , Interações Hospedeiro-Parasita/genética , Repetições de Microssatélites , Filogenia , Doenças das Plantas/genética , Animais , Primers do DNA/química , Marcadores Genéticos , Genótipo , Melhoramento Vegetal , Doenças das Plantas/imunologia , Doenças das Plantas/parasitologia , Imunidade Vegetal/genética , Reação em Cadeia da Polimerase , Locos de Características Quantitativas , Análise de Sequência de DNA , Glycine max/classificação , Glycine max/imunologia , Glycine max/parasitologia , Especificidade da Espécie , Tylenchoidea/crescimento & desenvolvimento , Tylenchoidea/patogenicidadeRESUMO
The family Myrtaceae is widespread in the Atlantic Forest and is well-represented in the Espírito Santo State in Brazil. In the genus Psidium of this family, guava (Psidium guajava L.) is the most economically important species. Guava is widely cultivated in tropical and subtropical countries; however, the widespread cultivation of only a small number of guava tree cultivars may cause the genetic vulnerability of this crop, making the search for promising genotypes in natural populations important for breeding programs and conservation. In this study, the genetic diversity of 66 guava trees sampled in the southern region of Espírito Santo and in Caparaó, MG, Brazil were evaluated. A total of 28 morphological descriptors (11 quantitative and 17 multicategorical) and 18 microsatellite markers were used. Principal component, discriminant and cluster analyses, descriptive analyses, and genetic diversity analyses using simple sequence repeats were performed. Discrimination of accessions using molecular markers resulted in clustering of genotypes of the same origin, which was not observed using morphological data. Genetic diversity was detected between and within the localities evaluated, regardless of the methodology used. Genetic differentiation among the populations using morphological and molecular data indicated the importance of the study area for species conservation, genetic erosion estimation, and exploitation in breeding programs.