Role of steroidal glycoalkaloid ?-tomatine in host-plant resistance of tomato to colorado potato beetle

Abstract

The role of the steroidal glycoalkaloid α-tomatine in the hostplant resistance of tomato to the Colorado potato beetle,Leptinotarsa decemlineata (Say) was examined in short- (24 hr; using first- and fourth-instar larvae) and long-term (first-instar larvae reared through the prepupal stage) feeding experiments. Consumption rate, growth rate, efficiency of conversion of ingested food to body mass, and survival were compared forL. decemlineata provided foliage from susceptible (Lycopersicon esculetum Mill. cv. Walter), resistant (L. hirsutum f.Glabratum C.H. Mull accession PI 134417), and F1 hybrid plants. Values obtained for dietetic indices were regressed against corresponding values for α-tomatine content of foliage provided to larvae. Differences in dietetic indices could not be attributed to variation in foliar α-tomatine content despite a long-standing literature showing theex planta α-tomatine inhibits feeding and growth byL. decemlineata.

Comparative Metabolite Profiling ofSolanum tuberosumagainst Six WildSolanumSpecies with Colorado Potato Beetle Resistance

“…Feature 7.94\1034.5581 was assigned to tomatine, which is a tomato glycoalkaloid associated with CPB resistance. 11 It was detectable in S. piurae at lower levels than dehydrocommersonine and was at very low levels in S. chomatophilum. Removal of the xylose sugar converts tomatine to β-tomatine.…”

“…Feature 11.34\411.0882 had a m/z that matched to newbouldiaquinone A, a metabolite from the medicinal plant Newbouldia laevis that is a naphthoquinone−anthroquinone coupled pigment. 48 11.34\587.2077 was matched with blestrianol C, a biphenanthrene isolated from the tubers of the orchid Bletillla striata. 49 Alternatively, the latter two features may be derived from the same unknown metabolite as they share the same retention time, indicating that 11.34\411.0882 could be a fragment ion of 11.34\587.2077.…”

Antinutritive and toxic components of plant defense against insects

“…The some of their natural enemies (Bloem et al, 1989;Campbell and Duffey, 1979;, has been well documented. Because of this chemical's ability to act as a detergent, forming water-insoluble complexes with cholesterol (Roddick, 1980(Roddick, , 1979(Roddick, , 1987 and thereby destroying the integrity of cell membranes by removal of cholesterol, tomatine is usually thought of as a "toxic" chemical (Barbour and Kennedy, 1991;Gallardo et al, 1990). Although detailed biochemical proof for this mechanism of action against insects is lacking, there is circumstantial evidence via use of digestive indices that tomatine is indeed toxic to insects (Bloem et al, 1989;Gallardo et al, 1990).…”

Susceptibility of Tuta absoluta (Meyrick) (Lep., Gelechiidae) reared on two species of Lycopersicon to Bacillus thuringiensis var. kurstaki

“…Lycopersicon hirsutum f. glabratum (PI 134417) has been cited as resistant to several tomato pests (L IN and T RUMBLE , 1986; F ARRAR and K ENNEDY , 1987a; V ENTURA and V ENDRAMIM , 1996). The leaves of genotype PI 134417 contain the alkaloid alpha‐tomatine (D UFFEY and I SMAN , 1981), which has an antibiotic effect on Helicoverpa zea (Boddie) and Leptinotarsa decemlineata (Say) (K ENNEDY , 1986; B ARBOUR and K ENNEDY , 1991). However, the high resistance of this genotype to insect attack is due to the allelochemicals 2‐tridecanone (W ILLIAMS et al., 1980; D IMOCK and K ENNEDY , 1983; K ENNEDY and S ORENSON , 1985) and 2‐undecanone present in the glandular trichomes type VI (F ARRAR and K ENNEDY , 1987b, 1988).…”