ABSTRACT
Introduction: The fiber of the Gynerium sagittatum Aubl. P. Beauv is raw material for the elaboration of several handcrafts, which are symbols of Colombian cultural identity. In the manufacture process, different genotypes are used according to the fiber quality and the type of craftsmanship, but it is believed that Gynerium is a complex species, and to date, there is no agreement on whether these genotypes belong to the same species or to different species. Objective: The aim of this study was to quickly and accurately identify wild cane plants using the nuclear ribosomal internal transcribed spacer (ITS1+ITS2), three chloroplast regions (matK, rbcL, ycf1), and their combinations. Methods: Different tests were used for discrimination: (1) inter and intraspecific distances, (2) Best Match (BM), Best Close Match (BCM), and tree-based method (3) Neighbor Joining (NJ) and (4) maximum likelihood and bayesian inference in molecular data. Results: The results showed that BM and BCM approaches revealed the low rate of correct species identification for ITS+matK (33.3 %) and ITS (28.6 %) loci, showing similarity among sequences. These results were further supported by tree-based analyses, where all individual regions and the different gene combinations had a zero discrimination rate. Conclusions: all genotypes belong to the same species of wild cane, therefore existing morphological differences can be related to phenotypic plasticity.
Introducción: La fibra de Gynerium sagittatum Aubl. P. Beauv, es materia prima esencial para la elaboración de varias artesanías, que son símbolos de la identidad cultural colombiana. En el proceso de fabricación, se utilizan diferentes genotipos de acuerdo con la calidad de la fibra y el tipo de artesanía, pero se cree que Gynerium es una especie compleja y hasta la fecha, no hay un consenso sobre si estos genotipos pertenecen a la misma especie o especies diferentes. Objetivo: Identificar de forma rápida y precisa plantas de caña silvestre utilizando el espaciador transcrito interno ribosomal nuclear (ITS1+ITS2), tres regiones de cloroplasto (matK, rbcL, ycf1) y sus combinaciones. Métodos: Se utilizaron diferentes pruebas para la discriminación: (1) distancias inter e intraespecíficas, (2) Prueba Best Match (BM), Best Close Match (BCM) y método basado en árboles (3) Neighbor Joining (NJ) y (4) Probabilidad de inferencia bayesiana mediante datos moleculares. Resultados: Los resultadosmostraron que los enfoques BM y BCM revelaron una baja tasa de identificación correcta de especies para los loci ITS+matK (33.3 %) e ITS (28.6 %), mostrando similitud entre las secuencias. Estos resultados fueron respaldados por análisis basados en árboles, donde todas las regiones individuales y las diferentes combinaciones de genes tuvieron una tasa de discriminación de cero (0 %). Conclusiones: los genotipos evaluados pertenecen a la misma especie de caña flecha y las diferencias morfológicas existentes pueden estar relacionadas con plasticidad fenotípica.
ABSTRACT
Growers appreciate Cattleya walkeriana and C. loddigesii due to striking shape and rarity. Thus, this study aimed to evaluate the feasibility of DNA barcode regions, namely ITS1, ITS2 and rpoC1, to discriminate between C. walkeriana and C. loddigesii species. DNA barcode regions were successfully amplified using primers designed to amplify plants. We also included sequences from public databases in order to test if these regions were able to discriminate C. walkeriana and C. loddigesii from other Cattleya species. These regions, and their combinations, demonstrated that the ITS1+ITS2 had the highest average interspecific distance (11.1%), followed by rpoC1 (1.06%). For species discrimination, ITS1+ITS2 provided the best results. The combined data set of ITS1+ITS2+rpoC1 also discriminated both species, but did not result in higher rates of discrimination. These results indicate that ITS region is the best option for molecular identification of these two species and from some other species of this genus.
As espécies Cattleya walkeriana e C. loddigesii são apreciadas pelos colecionadores devido às suas impressionantes forma e raridade. Este estudo teve como objetivo avaliar a viabilidade das regiões DNA barcode, ou seja, ITS1, ITS2 e rpoC1, para discriminar as espécies C. walkeriana e C. loddigesii. Regiões DNA barcode foram amplificadas com êxito utilizando os iniciadores desenhados para plantas. Nós também incluímos sequências de bases públicas de dados, a fim de testar se estas regiões foram capazes de discriminar C. walkeriana e C. loddigesii de outras espécies de Cattleya. Estas regiões e suas combinações demonstraram que o ITS1 + ITS2 teve a maior distância média interespecífica (11,1%), seguido por rpoC1 (1,06%). Para a discriminação das espécies, ITS1 + ITS2 proporcionaram os melhores resultados. Os dados combinados dos ITS1 + ITS2 + rpoC1 também discriminaram ambas as espécies, mas não resultaram em maiores taxas de discriminação. Estes resultados indicam que a região ITS é a melhor opção para a identificação molecular destas duas espécies e a partir de algumas outras espécies deste gênero.