Papel da 2-tridecanona e dos tricomas glandulares tipo VI na resistência do tomateiro a Tuta absoluta

Abstract

Resumo _ O metabólito secundário 2-tridecanona, secretado pelos tricomas glandulares tipo VI das folhas de tomateiro silvestre, Lycopersicon hirsutum L., confere-lhe resistência a uma grande variedade de insetos, inclusive a traça-do-tomateiro, Tuta absoluta (Meyrick). O objetivo do trabalho foi avaliar a concentração de 2-tridecanona, a densidade de tricomas glandulares tipo VI e o grau de infestação da traça-do-tomateiro na cultivar suscetível Uco Plata (Lycopersicon esculentum Mill.), na linhagem resistente PI 134417 (L. hirsutum f. glabratum) e em suas progênies F 1 e F 2 . Foram avaliadas ainda as possíveis associações entre a concentração de 2-tridecanona, a densidade de tricomas glandulares tipo VI e o grau de infestação da traça-do-tomateiro. O grau médio de infestação da traça-do-tomateiro em Uco Plata foi significativamente superior ao obtido em PI 134417. Ainda que a concentração de 2-tridecanona tenha sido significativamente superior no parental resistente, a presença deste metabólito somente explicaria parcialmente a resistência (R 2 = 8,17%). Não se detectaram diferenças significativas na densidade de tricomas tipo VI entre o parental suscetível e o resistente. Este comportamento ocorreu independentemente do conteúdo de 2-tridecanona e do grau de infestação da traça-do-tomateiro.Termos para indexação: Lycopersicon hirsutum, herbívoros, infestação, metabólicos, resistência a pragas. Role of 2-tridecanone and type VI glandular trichome on tomato resistance to Tuta absolutaAbstract _ The secondary metabolite 2-tridecanone, secreted by the type VI glandular trichomes present in the leaves of Lycopersicon hirsutum L., make it resistant to a great variety of insects, including the tomato pinworm, Tuta absoluta (Meyrick). The 2-tridecanone concentration, the type VI glandular trichome densities and the pinworm infestation degree were evaluated on the Lycopersicon esculentum Mill. susceptible cultivar Uco Plata, on the Lycopersicon hirsutum f. glabratum resistant accession PI 134417 and on their F 1 and F 2 . The mean infestation degree with pinworm larvae was significantly higher in Uco Plata than in PI 134417. The 2-tridecanone concentration was significantly higher in the resistant parent, but the presence of this metabolite could only partially account for the resistance (R 2 = 8.17%). No significant differences were detected in the type VI glandular trichomes densities between the susceptible and resistant parents. This trait was independent of the 2-tridecanone level and the pinworm infestation degree.

Biological performance and oviposition preference of tomato pinworm Tuta absoluta when offered a range of Solanaceous host plants

“…A possible explanation for this result could be the low mortality of the immature stages (larvae and pupae) (24%) and high female fecundity (211.88 eggs) following development on tomato and potato plants (13% and 188 eggs). These results are different to those obtained by Pereyra and Sanchez 20 and Kanle Satishchandra et al 45 , who documented a higher R 0 on tomato (49 and 52.15) in relation to potato (14 and 27.60). We attribute these differences to the plant varieties and genetic differences between T. absoluta populations used by each research group.…”

“…Interestingly, the survival rate of the immature stages was higher on potato than on tomato plants. Tomato plants are rich in trichomes, anti-feedant proteins, toxins and protease inhibitors that protect them against pest attack 20 , 34 , 35 . The movement of early larval instar T. absoluta on the surface of tomato plants is made more difficult because of their small size and the presence of protective barriers (trichomes and hairs) on the leaf surface 36 , 37 .…”

Indirect selection of industrial tomato genotypes that are resistant to spider mites (Tetranychus urticae)

“…For instance, resistance obtained from S. pennellii has been associated with the presence of allelochemicals called acyl sugars. These sugars confer a sticky aspect to the leaf surface that serves as a natural trap, interferes in oviposition and feeding, and has a deleterious effect on the development of certain arthropod stages (Gillardón et al, 2001;Resende et al, 2009). The introduction of resistance to spider mites in S. lycopersicum tomato genotypes from a wild species (S. pennellii) is an effective way to obtain cultivars with high acyl sugar content in the leaflet and consequently a good resistance level (Maciel et al, 2011).…”

Insecticidal activity of 2-tridecanone against the cowpea weevil Callosobruchus maculatus (Coleoptera: Bruchidae)

“…Mull, to many arthropod pests including the tobacco hornworm, Manduca sexta (L.) (Williams et al 1980), the tomato fruitworm Heliothis zea (Boddie) (Williams et al 1980), the Colorado potato beetle, Leptinotarsa decemlineata (Say.) (Kennedy et al 1991), and the tomato pinworm, Tuta absoluta (Meyrick) (Gilardon et al 2001) was conditioned by large amounts of the 2-tridecanone (Fig. 1) in the type VI glandular trichomes.…”