ABSTRACT
Introducción: la capacidad antioxidante presente en las plantas ha despertado gran interés debido al potencial aprovechamiento en la alimentación para la prevención de enfermedades asociadas a estrés oxidativo. Objetivo: evaluar el efecto de la inducción con CuCl2 y Paraquat® (dicloruro de 1,1'-dimetil-4,4'-bipiridilo) sobre protoplastos y plántulas de las especies relacionadas de tomate, Lycopersicon hirsutum Dunal y Lycopersicon esculentum Mill. Métodos: la producción de especies reactivas de oxígeno se evaluó mediante citometría de flujo en protoplastos de las 2 especies de tomate, inducidos con CuCl2 y Paraquat® (dicloruro de 1,1'-dimetil-4,4'-bipiridilo). Adicionalmente, sobre las plántulas se evaluó el contenido de polifenoles totales y la capacidad atrapadora de radicales libres. Resultados: la inducción con Paraquat® durante eventos tempranos mostró un aumento en la producción de especies reactivas de oxígeno en 17,4 veces en protoplastos de Lycopersicon hirsutum y de 12,4 veces en Lycopersicon esculentum con respecto a sus respectivos controles no tratados. La especie Lycopersicon esculentum presentó velocidades de producción significativas de contenido de polifenoles totales y capacidad atrapadora de radicales libres con valores de 1,81 Eq ácido gálico hora-1 y 5,3 % de decoloración del DPPH hora-1, respectivamente. Durante la inducción con Paraquat® se observó una correlación entre contenido de polifenoles totales y capacidad atrapadora de radicales libres cercana a 1 y altamente significativa, en respuesta a los 2 tipos de inducción durante los eventos tempranos. Conclusiones: los resultados sugieren que la biosíntesis de compuestos fenólicos y la correlación con la capacidad atrapadora de radicales libres, no necesariamente se encuentra relacionada con una actividad antioxidante como un mecanismo de defensa a nivel celular.
Introduction: the antioxidant capacity in plants has aroused great interest due to their potential use in food for the prevention of oxidative stress-associated diseases. Objectives: to evaluate the effect of CuCl2 and Paraquat® induction on protoplasts and tomato seedlings belonging to Lycopersicon hirsutum Dunal and Lycopersicon esculentum Mill. species. Methods: the production of reactive oxygen species in protoplasts of tomato both species after exposure to CuCl2 and Paraquat® (1.1'-dimethyl-4.4'-bipiridyl dichloride) was evaluated by flow cytometry. Tomato seedlings were evaluated for total polyphenol content and free radical scavenging. Results: Paraquat® induction showed a 17.4 fold increase in reactive oxygen species production for L. hirsutum protoplasts and a 12.4 fold for L. esculentum during early events with respect to their respective untreated controls. L. esculentum showed significant slopes for free radical scavenging and total polyphenol content: 1.81 galic acid eq per hour and 5.3 % DPPH discoloration per hour, respectively. In addition, in response to the two kinds of induction, positive slopes and a correlation between total polyphenol content and free radical scavenging were observed with copper induction (correlation close to 1 and highly significant), but not significant models during Paraquat® induction. Conclusions: these results suggest that the biosynthesis of phenolic compounds and the correlation with the free radical scavenging are not necessarily related to antioxidant activity as a cellular defense mechanism.
ABSTRACT
In Brazil, no commercial tomato (Solanum lycopersicum L. formerly Lycopersicon esculentum Mill.) varieties are available which are resistant to the late blight, one of the most important tomato diseases, produced by the phytopathogenic oomycete Phytophthora infestans. The wild tomato (Solanum habrochaites Knapp & Spooner, formerly Lycopersicon hirsutum Dunal) shows resistance to P. infestans, because of which we investigated an interspecific cross between S. lycopersicum cv. Santa Clara and S. habrochaites accession BGH 6902 maintained at the Horticultural Germplasm Bank at the Federal University of Viçosa (Banco de Germoplasma de Horticultura (BGH), Universidade Federal de Viçosa (UFV), Viçosa, Minas Gerais, Brazil) The genitors, F1, F2, BC1 and BC2 were used to study the inheritance of resistance to P. infestans and to estimate the genetic parameters associated with resistance. Analysis of the area under the disease progress curve (AUDPC) indicated that inheritance is polygenic and that dominance controls character, whereas mean analysis showed that the additive effect was the most important. Although the character presents variability, the heritability is low which generates the need to better control the environment to obtain success with the selection.
ABSTRACT
This study evaluated, under laboratory conditions, the effect of tomato genotypes (Lycopersicon esculentum, cv. Santa Clara, Stevens and IPA-5; L. hirsutum f. glabratum, line PI 134417 and L. peruvianum line LA 444-1) on biology and oviposition of Tuta absoluta (Meyrick). The least adequate to the insect was LA 444-1 prolonging larval and pupal stages and reducing larval viability, pupal weight, fecundity and adult longevity, when compared to the control ('Santa Clara'). Line PI 134417 increased length of larval and pupal stages and reduced female pupae weight. Among cultivated tomato genotypes, the worst insect development occurred on 'IPA-5'. In this case, the length of larval and pupal stages increased and larval viability and weight of male pupae reduced. 'Stevens' was the only genotype which did not affect insect development when compared to control. Oviposition of T. absoluta was lower on wild tomatoes (PI 134417 and LA 444-1) than on cultivated genotypes, in free choice tests. Line PI 134417 was the only non-preferred to oviposition in a no choice test.
Avaliou-se, em condições de laboratório, o efeito de genótipos de tomateiro (Lycopersicon esculentum, cultivares Santa Clara, Stevens e IPA-5; L. hirsutum f. glabratum, linhagem PI 134417 e L. peruvianum, linhagem LA 444-1) sobre a biologia e oviposição de Tuta absoluta (Meyrick). A linhagem LA 444-1 foi, dentre os genótipos avaliados, a menos adequada à traça, provocando, em relação à testemunha ('Santa Clara'), alongamento das fases larval e pupal e redução na viabilidade larval, no peso de pupas, na fecundidade e na longevidade de adultos. A linhagem PI 134417 provocou alongamento das fases larval e pupal e redução no peso de pupas fêmeas. Dentre os materiais comerciais, o pior desenvolvimento do inseto ocorreu na cultivar IPA-5, onde houve alongamento das fases larval e pupal, redução na viabilidade larval e no peso de pupas machos. 'Stevens' foi o único genótipo que não afetou o desenvolvimento da traça quando comparado à testemunha. A oviposição de T. absoluta foi menor nos dois genótipos selvagens (PI 134417 e LA 444-1) do que nos materiais comerciais, em teste com chance de escolha. Em condições de confinamento, apenas a linhagem PI 134417 foi não preferida para oviposição.