Cultura de tecidos e monitoramento da estabilidade genética e metabólica de plantas de Petiveria alliacea L. produzidas e conservadas in vitro

Abstract

Plant tissue culture is an important tool for germplasm and metabolites production and/or storage. This study aimed at the the establishment of ttissue culture and cryopreservation systems for Petiveria alliacea, an importante medicinal species, which is widely used in folk medicine and African-Brazilian rituals. Plants from five populations from the state of Rio de Janeiro were studied. In order to control the materials produced and maintained in vitro , methodologies for assessing the genetic variability, through molecular markers, phytochemicals and the genotoxic and/or antigenotoxic effects of the extracts have been established. Among the different methods used for the production of clones, (i) the multiplication from shoot tips in response to different cytokinins, in different concentrations, provided 4-5 plants per explant, depending on the population and the type of cytokinin used; (ii) somatic embryos were induced with different growth regulators, directly and indirectly, from leaves and roots of in vitro -grown plants, displaying a high multiplication capacity and potential for conversion to plants; (iii) adventitious root cultures were obtained in response to different concentrations of auxins (IAA, NAA, IBA, 2,4-D), and long, individual roots were obtained only in the presence of 1.02 uM IBA, with the formation "skeins" and somatic embryos in response to the other types and concentrations of auxins. The assessment of phytochemical profile by chromatographic methods and molecular stability by RAPD were applied in plant materials maintained in the field or under in vitro conditions. Different polysulfides were observed by HPLC, in all evaluated materials, which were considered good biosynthetic markers for monitoring the material produced and maintained in vitro . In RAPD, primers were determined six primers able to identify genetic variations among the populations studied, furthermore were determined nine primers capable of identifying polymorphisms among clones were determined. The investigation of the toxic effects of the aqueous extracts on the plasmidial DNA showed that they were able to induce structural changes in DNA conformation, indicating the occurrence of breakages, depending on the concentration. In addition, a protective effect was observed against the oxidative damage caused by stannous chloride, also indicating a potential antigenotoxic effect. Thus, the assessment of the genetic, phytochemical and biological stability carried out in this work allowed the characterization and control of the germplasm of P. alliacea produced and maintained under in vitro conditions