Resistance to the South American tomato pinworm Tuta absoluta in high acylsugar and/or high zingiberene tomato genotypes

Abstract

Zingiberene (ZGB) and acylsugars (AS) are allelochemicals responsible for high levels of arthropod resistance found in Solanum habrochaites (= Lycopersicon hirsutum) var. hirsutum 'PI 127826' and S. (= L.) pennelli 'LA 716', respectively. These accessions were used to develop commercial lines with good levels of pest resistance. The objective of the present work was to assess the ZGB and AS contents and the levels of resistance to Tuta absoluta in tomato hybrids between high ZGB 9 high AS lines, as compared with their parental lines and with commercial checks. High AS homozygous lines [TOM-688 and TOM-689, both originated from the interspecific cross S. lycopersicum (= L. esculentum) 9 S. pennelli], high ZGB homozygous lines (ZGB-703 and ZGB-704, both derived from the interspecific cross S. lycopersicum 9 S. habrochaites var. hirsutum), double heterozygotes for both ZGB and AS, single heterozygotes for ZGB, and single heterozygotes for AS were assessed for AS and ZGB contents. Low-ZGB low-AS checks 'Débora Max' and 'TOM-684' were used, as well as checks with high ZGB (PI 127826) and high AS (LA 716). The genotypes were submitted to infestation with South American tomato pinworm adults in a screenhouse, and oviposition counts were taken 10 days after the initial infestation date. Plants were scored for overall plant damage and percent leaflets attacked up to the 38th day after infestation. Genotypes heterozygous for ZGB or AS showed allelochemical contents intermediate to those of their high and low content parents, indicating incompletely dominant gene action for contents of each of the allelochemicals. There were no significant differences in T. absoluta oviposition between high-AS homozygous genotypes, high-ZGB homozygotes, single heterozygotes for AS, single heterozygotes for ZGB and double heterozygotes for ZGB and AS, but all these genotypes showed egg counts significantly lower than the low-ZGB low-AS checks. Feeding damage of T. absoluta was higher in the low-ZGB low-AS checks than in any other ZGB-rich or AS-rich tomato genotype. Relative to ZGB or AS single heterozygotes, the heterozygotes for both ZGB and AS showed higher levels of resistance to the insect, as measured by overall plant damage, indicating a synergic effect of the allelochemicals on resistance.

Selection of tomato genotypes for processing with high zingiberene content, resistant to pests

“…These results are in accordance with that found by Azevedo et al (2003); Maluf et al (2007Maluf et al ( , 2010, Oliveira et al (2012) and Neiva et al (2013) who verified that high ZGB contents, together with high density of glandular trichomes, promote resistance of plants to spider mite, whitefly and tomato leafminer. According to Gonçalves et al (2006), high ZGB content is directly linked to high density of glandular trichomes.…”

Economic injury level and crop loss assessment for Tuta absoluta (Lepidoptera: Gelechiidae) on different tomato cultivars

“…Although all the leaves of all seven tomato cultivars were infested by T. absoluta larvae, only "Petomech," "Cal JN3," "Rio Grande" and "Early Urbana Y" cultivars had significant yield loss in both years. This could be due to the morphological or biochemical characteristics of each tomato cultivar (Azevedo, Faria, Maluf, Oliveira, & Freitas, 2003;Maluf, Silva, & Cardosa, 2010). Oliveira, Júnior, Maluf, Neiva, and Maciel (2012) demonstrated that genotypes associated with high densities of glandular trichomes were less favourable to T. absoluta, but whether that was the case with these cultivars remains to be studied.…”

Comparative damage and digestive enzyme activity of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) on 12 tomato cultivars

“…In a previous study, we investigated life history and life table parameters of T. absoluta on these cultivars (Nouri-Ganbalani et al 2016). For example, at least three types of secondary metabolites, namely acyl sugars, zingiberene, and 2-tridecanone, are known in association with tomato resistance to T. absoluta (Maluf et al 2010;de Oliveira et al 2012). In line with these results, many studies have reported that the life parameters of and damage caused by T. absoluta vary significantly when the pest is reared on different tomato cultivars, and that these variations may arise from differences in the quality and quantity of nutrients, phagostimulant factors, trichome density, and the abundance of secondary metabolites among cultivars (Pereyra & Sanchez 2006;Proffit et al 2011;de Oliveira et al 2012;Sohrabi et al 2016b;Ghaderi et al 2017).…”