RESUMO
Promoting neglected and underutilized crop species is a possible solution to deal with the complex challenges of global food security. Chayote is a Neglected and Underutilized Cucurbit Species (NUCuS), which is recognized as a fruit vegetable in Latin America and is widely grown in Asia and Africa. However, basic biological knowledge about the crop is insufficient in scientific sources, especially outside of its center of origin. In this study, limited observations on reproductive characters were conducted, differentiating accessions from Mexico, Japan, and Myanmar. Cytological evaluation among Mexican and Japanese accessions showed that the relative nuclear DNA content is 1.55 ± 0.05 pg, the estimated genome size is 1511 at 2C/Mbp, and the observed mitotic chromosomal number is 2n = 28. The genetic diversity of 21 chayote accessions was also examined using six microsatellite markers. A global low genetic heterozygosity (Ho = 0.286 and He = 0.408) and three genetic groups were detected. The results established the basis to provide insights into chayote arrival history in Asia by looking at the crop's reproductive morphology, cytology, and genetic diversity status outside its origin center. This could help in developing sustainable utilization and conservation programs for chayote.
RESUMO
Sechium edule (Jacq.) Sw. (Cucurbitaceae) is a species native to Mexico and Central America. The collection, characterization, and evaluation of accessions maintained in genebanks is essential for the conservation of this species. However, there are no specific varietal descriptors that differ from those used in a phenetic approach and are adapted to international registration guidelines to help distinguish, improve, cluster, and protect intraspecific variants of common use and those obtained by breeding. Therefore, 65 morphological descriptors (qualitative and quantitative) were evaluated in 133 accessions obtained from Mexico, Guatemala, and Costa Rica located in the National Germplasm Bank of S. edule in Mexico. These characteristics were observed to be phenetically stable for five generations under the same agroclimatic conditions. In addition, an analysis of amplified fragment length polymorphism (AFLP) was applied to 133 samples from a set of 245 accessions. According to the multivariate analysis, 26 of the 65 descriptors evaluated (qualitative and quantitative) enabled differentiation of varieties of S. edule. The AFLP analysis showed a high level of polymorphism and genetic distance between cultivated accessions and their corresponding wild ancestor. The variations in S. edule suggest that the morphological characteristics have differentiated from an essentially derived initial edible variety (ancestral original variety), but unlike other cucurbits, there is no evidence of the ancestral edible for Sechium since the seed is unorthodox and there are no relicts.
RESUMO
Bioprospecting identifies new sources of compounds with actual or potential economic value that come from biodiversity. An analysis was performed regarding bioprospecting purposes in ten genotypes of Sechium spp., through a meta-analysis of 20 information sources considering different variables: five morphological, 19 biochemical, anti-proliferative activity of extracts on five malignant cell lines, and 188 polymorphic bands of amplified fragment length polymorphisms, were used in order to identify the most relevant variables for the design of genetic interbreeding. Significant relationships between morphological and biochemical characters and anti-proliferative activity in cell lines were obtained, with five principal components for principal component analysis (SAS/ETS); variables were identified with a statistical significance (< 0.7 and Pearson values ≥ 0.7), with 80.81% of the accumulation of genetic variation and 110 genetic bands. Thirty-nine (39) variables were recovered using NTSYSpc software where 30 showed a Pearson correlation (> 0.5) and nine variables (< 0.05), Finally, using a cladistics analysis approach highlighted 65 genetic bands, in addition to color of the fruit, presence of thorns, bitter flavor, piriform and oblong shape, and also content of chlorophylls a and b, presence of cucurbitacins, and the IC50 effect of chayote extracts on the four cell lines.
Assuntos
Bioprospecção , Cucurbitaceae , Cucurbitacinas/farmacologia , Frutas/química , Extratos Vegetais/farmacologia , Animais , Linhagem Celular , Cucurbitaceae/química , Cucurbitaceae/classificação , Cucurbitaceae/genética , Genótipo , Humanos , Camundongos , Polimorfismo GenéticoRESUMO
Natural products are in great demand because certain secondary metabolites (SMs) are sources of antioxidants, flavorings, active substances, or anticancer agents with less aggressiveness and selectivity, among which triterpenes and flavonoids are of importance because they inhibit carcinogenesis. For Sechium spp. P. Br. (chayotes), there is scientific evidence of antiproliferative activity that has occurred when cancer cell lines have been treated with this fruit. In order to compare future therapeutic designs and identify new and ancestral characteristics, triterpenes and flavonoids were determined in contrasting Sechium genotypes. The obtained data were analyzed via a cladistics approach, with the aim of identifying the characteristics and state of phytochemicals and genetic variables. The concentrations of flavonoids and triterpenes were determined, and a more complex composition of secondary metabolites was found in the wild types as compared to their domesticated genotypes. Bitter fruits contained a higher number of SMs, followed by those with a neutral and sweet flavor. A cladogram showed the differentiation of the three groups based on the flavor of the fruits. The diversity of SMs decreases in evolutionary terms, in response to domestication and environmental adaptation. Therefore, genotypes can be feasibly selected based on fruit flavor for gross-breeding, and cytotoxicity can be reduced without losing possible therapeutic effects.
RESUMO
A preliminary characterization was undertaken to describe genetic structure of mango ginger (Curcuma amada) acquired from farmers and ex situ genebank in Myanmar using neutral (rice SSR based RAPDs) and functional genomic (P450 based analog) markers. The high polymorphism (> 91 percent) depicted has displayed existence of genetic variability in the germplasm investigated. Large number of source-specific alleles (neutral-markers = 78, functional-markers = 63) was amplified which revealed that neutral regions of the mango ginger were more variable compared with the functional regions. The major fraction of the molecular variance (neutral-markers = 85 percent, functional-markers = 93 percent) was explained within germplasm acquisition sources and this tendency was also supported by the estimate of gene diversity. The genebank accessions have shown comparatively more genetic variability than farmers' accessions. The variability observed in mango ginger may possibly be associated with the long history of its cultivation under diverse ecological conditions. The two marker systems elucidated their high resolving power which detected variability even in fewer genotypes assayed. As the target sites of these markers are different, therefore, the variability detected is believed to cover diverse part of the genome together with neutral and functional regions. We found the concurrent use of the different types of molecular markers valuable to comprehend a dependable variability pattern in the germplasm assayed.