Glandular trichomes of Solatium berthaultii and resistance to the Colorado potato beetle

Abstract

The defensive mechanisms of the wild potato, Solanum berthaultii Hawkes, to larvae of the Colorado potato beetle, Leptinotarsa decemlineata (Say), were studied by selective removal of glandular trichomes and trichome exudates from leaflets, and by comparing performance on S. berthaultii and on the cultivated potato, S. tuberosum L., which lacks defensively active type A and B glandular trichomes. Removal of type A trichomes increased the proportion of larvae that fed on S. berthaultii. Removal of the exudate from type B trichomes increased the proportion of larvae that fed and led to a decrease in mortality. The predominant active compounds in type B exudate, i.e. fatty acid esters of sucrose, were only effective in the presence of type A trichomes. Sucrose esters did not affect larval feeding on S. tuberosum leaflets or on S. berthaultii leaf discs from which the type A trichomes had been removed. Growth of surviving larvae was not significantly affected by removing type A trichomes or type B exudate. Growth of larvae was significantly increased when S. berthaultii leaflets were presented in artificial diet which eliminated the physical barrier of the type B stalks. Growth was no different on artificial diet containing either S. berthaultii or S. tuberosum leaf material (fresh or lyophilized powder) but was poorer on these diets than on S. tuberosum leaflets. The presence of type A trichomes is a fundamental requirement for expression of S. berthaultii resistance to L1 L. decemlineata. Type B droplets containing sucrose esters increase the expression of resistance in the presence of defensively-active type A trichomes.

Adaptations of two specialist herbivores to movement on the hairy leaf surface of their host, Solanum guaraniticum Hassl (Solanaceae)

“…Evidences from cultivated and wild plants support the idea that trichomes act as mechanical defense that impede movement on leaf surface, restrict access to food and/or diminish food digestibility and assimilation (Schillinger & Gallun 1968;Gilbert 1971;Rathcke & Pool 1974;Pillemer & Tingey 1976;Belcher & Thurston 1982;Brewer et al 1983;Smith & Grodowitz 1983;Ramalho et al 1984;Hoffman & McEvoy 1986;Fordyce & Agrawal 2001;Valverde et al 2001;Kennedy 2003). In addition to mechanical defense, some plant glandular trichomes secret toxic chemicals and/or sticky exudates that may entrap and kill small insects (Thurston 1970;Smith et al 1975;Tingey & Gibson 1978;Shade et al 1979;Tingey & Laubengauer 1981;Duffey 1986;Neal et al 1989;Yencho & Tingey 1994;van Dam & Hare 1998;Gurr & McGrath 2002).…”

“…Five of them are known to feed on Solanum L. (Solanaceae) and tend to be host specific (Siebert 1975;Buzzi 1988Buzzi , 1994Borowiec 1996Borowiec , 1999Olckers et al 2002). The effects of Solanum trichomes as a defense mechanism against herbivores are widely studied, mainly regarding the role of their exudates (Gibson 1978;Tingey & Gibson 1978;Obrycki & Tauber 1984;Gregory et al 1986;Neal et al 1989;Yencho & Tingey 1994;Hill et al 1997). However, the corresponding mechanical effects are relatively poorly explored.…”

Aphid resistance in potato

“…Трихомы типа А содержат полифенолоксидазу, пока не идентифи цированное вещество, и смесь сесквитерпенов, а сложные эфиры, продуцируемые волосками В, повышают экспрес сию устойчивости в присутствии волосков A (Neal et al, 1989). Показано, что волоски типа В содержат феромон тревоги тлей (E)βфарнезен (Gibson, Pickett, 1983).…”

Green Peach Aphid (Homoptera: Aphididae) Action Thresholds for Controlling the Spread of Potato Leafroll Virus in Idaho

“…High levels of -chaconine and -solanine also have negative impacts on M. persicae adults, lowering feeding and fecundity, and increasing mortality (Fragoyiannis et al 1998). Antixenosis-based resistance may be conferred by glandular trichomes (Gibson 1971(Gibson , 1976aTingey and Gibson 1978;Tingey and Laubengayer 1981;Neal et al 1990;Pelletier and Smilowitz 1990;Yencho and Tingey 1994;Alvarez et al 2006;Pelletier and Dutheil 2006). Glandular trichomes are known to alter the ability of many herbivores to colonize, forage, and survive on the plant.…”

“…Glandular trichomes are known to alter the ability of many herbivores to colonize, forage, and survive on the plant. For example, glandular trichomes reduce the proportion of L. decemlineata larvae feeding on S. polyadenium and S. berthaultii leaves and increase larval mortality (Gibson 1976b;Neal et al 1989). …”