Trichomes of Lycopersicon species and their hybrids: effects on pests and natural enemies

Abstract

1 The cultivated tomato, Lycopersicon esculentum , is an economically important worldwide crop. Current pest management techniques rely heavily on pesticides but trichome-based host-plant resistance may reduce pesticide use. 2 A review of the literature is provided on trichomes of wild Lycopersicon species and the effects of trichome-based host-plant resistance on arthropods. Solvents have been used to remove glandular trichome exudates and the resulting dimminution of their effects quantified. Correlational approaches to assess the relationship between the different trichome types and effects on pests have also been used. 3 Most studies have focused on Lepidoptera and Hemiptera, although some work has included Coleoptera, Diptera and Acarina, and both antibiotic and antixenotic effects have been demonstrated. 4 Natural enemies are a cornerstone of international pest management and this review discusses how the compatibility of this approach with trichome-based hostplant resistance is uncertain because of the reported negative effects of trichomes on one dipteran, one hemipteran and several Hymenoptera. 5 For trichome-based host-plant resistance to be utilized as a pest management tool, trichomes of wild species need to be introgressed into the cultivated tomato. Hybrids between the cultivated tomato and the wild species Lycopersicon hirsutum f. glabratum , Lycopersicon pennellii and Lycopersicon cheesmanii f . minor have been produced and useful levels of resistance to Acarina, Diptera and Hemiptera pests have been exhibited, although these effects may be tempered by effects on natural enemies. 6 This review proposes that studies on genetic links between fruit quality and resistance, field studies to determine the compatibility of natural enemies and trichome-based host-plant resistance, and a strong focus on L. cheesmanii f. minor , are all priorities for further research that will help realize the potential of this natural defence mechanism in pest management.

Caracterização morfoagronômica preliminar de acessos de pimentas cumari

“…Uma das formas seria como barreira química, liberando substâncias que podem ter efeito sobre alimentação, oviposição e sobrevivência, dentre outros aspectos (Krips et al, 1999;Mishalska, 2003;Simmons & Gurr, 2005), ou mesmo, compondo uma barreira física ao seu deslocamento na (Genda et al, 2005).…”

Insects had it first: surfactants as a defence against predators

“…The effectiveness of different OS types did not depend on the ingested diet on which the insects had been reared because OS produced from artificial diet evoked the same grooming responses in ants as OS from two different host plants ( figure 1). This suggests that potentially deterrent secondary compounds such as terpenes or alkaloids in tomato ( Yahara et al 2004;Simmons & Gurr 2005) or furanocoumarins in the leaves of celery (Lombaert et al 2001) were either not present in the OS or the ants did not mind them. The lack of secondary compound effects was further confirmed by deterrence tests with both ant species (figure 2).…”

In vitro reconstruction and analysis of evolutionary variation of the tomato acylsucrose metabolic network

“…Some trichome-produced metabolites have documented direct and indirect antiherbivore activities (4,(6)(7)(8). For example, acylsugars are a group of structurally related specialized metabolites produced in plants of the nightshade family-the Solanaceae (9,10).…”