ABSTRACT Stevia rebaudiana (Bertoni) Bertoni, Asteraceae, is used as a food additive because its leaves are a source of steviol glycosides. There are examples of tissue culture based on micropropagation and phytochemical production of S. rebaudiana leaves but there are few studies on adventitious root culture of S. rebaudiana. More than 90% of the plants used in industry are harvested indiscriminately. In order to overcome this situation, the development of methodologies that employ biotechnology, such as root culture, provides suitable alternatives for the sustainable use of plants. The aim of this study was to compare morpho-anatomical transverse sections of S. rebaudiana roots grown in vitro and in vivo. The in vitro system used to maintain root cultures consisted of a gyratory shaker under dark and light conditions and a roller bottle system. Transverse sections of S. rebaudiana roots grown in vitro were structurally and morphologically different when compared to the control plant; roots artificially maintained in culture media can have their development affected by the degree of media aeration, sugar concentration, and light. GC–MS and TLC confirmed that S. rebaudiana roots grown in vitro have the ability to produce metabolites, which can be similar to those produced by wild plants.

A proposta deste estudo foi avaliar diferenças químicas, fisiológicas e genéticas em sementes de cactos do gênero Cereus (mandacaru) cultivadas nas regiões Nordeste (Picos, Estado do Piauí) e Sul (Maringá, Estado do Paraná) do Brasil. No período de oito dias, as temperaturas de 25°C e 30°C foram igualmente adequadas para a germinação de todas as sementes. O ácido oleico (C18:1) foi o ácido graxo mais comum encontrado nas sementes coletadas nas regiões Sul (41%) e Nordeste (45,5%). A análise de lipases indicou que as sementes de Maringá têm alta heterozigosidade média observada e esperada e que as sementes de Picos têm número mais alto de alelos por locos. Portanto, as sementes de mandacaru da região semiárida do Nordeste assim como as sementes do Sul (as duas regiões contrastantes do Brasil) são promissoras para a preservação da biodiversidade no genoma de mandacaru. A baixa identidade genética entre as sementes de Maringá e de Picos na análise do loco Lipase-5 (I = 0,77) sugere que as plantas de mandacaru de Maringá e de Picos podem corresponder a duas espécies: C. peruvianus e C. jamacaru, respectivamente.

The purpose of this study was to evaluate the chemical, physiological and genetic differences in seeds of cactus of the Cereus genus (mandacaru) cultivated in the Northeast (Picos, State of Piauí) and Southern (Maringá, State of Paraná) regions of Brazil. Over a period of eight days, temperatures of 25°C and 30°C were equally efficient for the germination of all the seeds. Oleic acid (C18:1) was the most common fatty acid found in the seeds collected in the Southern (41%) and Northeast (45.5%) regions. The analysis of lipases indicated that seeds from Maringá have high mean observed and expected heterozygosities and that seeds from Picos have a higher number of alleles per loci. Therefore, the seeds of mandacaru from the semiarid region of Northeast as well as the seeds from the South (the two contrasting regions of Brazil) are promising with regards to the preservation of the biodiversity in the genome of mandacaru. The low genetic identity between mandacaru seeds from Maringá and Picos at Lipase-5 locus analysis (I = 0.77) suggests that the mandacaru plants from Maringá and Picos may correspond to two species: C. peruvianus and C. jamacaru, respectively.

Em um levantamento conduzido na região noroeste do Paraná, principal região produtora de mandioca do estado, constatou-se que o CsCMV está amplamente disseminado, infectando mais de 90% das plantas de todas as cultivares. Um isolado do CsCMV foi purificado para a produção de um anti-soro policlonal de alto título (1/1000), o qual foi utilizado na indexação por meio de PTA-ELISA de plantas produzidas via cultura de meristemas. De uma produção inicial de 110 plantas da cultivar Olho Junto, 31 permaneceram infectadas como indicou o PTA-ELISA. Visando aumentar a sensibilidade de detecção do vírus, foi estabelecido um protocolo de IC-RT-PCR. A IgG purificada, específica para o vírus, combinada com um par de oligonucleotídeos universais para Potexvirus, prontamente detectou o CsCMV nos extratos obtidos de mandioca. Produtos de IC-RT-PCR de 750 pb foram amplificados a partir de seis de um total de 35 plantas previamente testadas como negativas para o CsCMV via PTA-ELISA. Os sequenciamentos confirmaram que os produtos de IC-RT-PCR são parte do gene codificador da replicase do CsCMV, indicando assim a presença do vírus mesmo após a termoterapia combinada com a cultura de meristemas. O PTA-ELISA permitiu a triagem preliminar de plantas vírus-positivas, possibilitando a redução do número de plantas a serem analisadas por IC-RT-PCR. Embora o CsCMV seja considerado de importância menor, o fato desse vírus estar disseminado na região noroeste do Paraná recomenda a adoção de medidas efetivas para o seu controle.

A virus survey conducted in the northwest region of Paraná, the main cassava-producing region of that state, showed Cassava common mosaic virus (CsCMV) to be widespread, infecting more than 90% of plants from all cassava cultivars. A CsCMV isolate was purified and used to raise a high-titer (1/1.000) polyclonal antiserum for indexing plants produced from meristem-tip culture, using PTA-ELISA. From an initial production of 110 plants of cultivar Olho Junto, 31 remained infected as indicated by PTA-ELISA. To improve the sensitivity of virus detection, an immunocapture-RT-PCR (IC-RT-PCR) protocol was established. Virus-specific IgG, purified and combined with a primer set for the genus Potexvirus, could readily detect CsCMV in cassava crude leaf extracts. IC-RT-PCR products of 750 bp were amplified from six out of 35 plants previously tested as virus-negative by PTA-ELISA. Sequence analysis of cloned IC-RT-PCR products confirmed they were part of the CsCMV replicase gene, indicating that the virus was still present after thermotherapy and meristem-tip culture. PTA-ELISA enabled initial screening of virus-positive cassava, reducing the number of plants to be further analyzed by IC-RT-PCR. Though CsCMV has been considered of minor importance, its widespread nature, as noticed in Paraná, indicates the need for adoption of effective control measures.