Ecological costs and benefits are correlated with trypsin protease inhibitor production in Nicotiana attenuata.

GLAWE, G.A.; ZAVALA, J.A.; KESSLER, A.; VAN DAM, N.; BALDWIN, I.T.

ECOLOGY

Año: 2003 vol. 84 p. 79 - 90

0012-9658

Abstract. Genotypes of the wild tobacco Nicotiana attenuata from different geographic regions in North America vary considerably in the level of constitutive and inducible trypsin protease inhibitors (TrypPIs), a potent direct defense, as well as in the production of herbivore-induced volatiles that function as indirect defense. Genotypes collected from Arizona were found to lack the ability to produce TrypPIs at a transcriptional level, had decreased volatile production, but exhibited nicotine and growth responses that were not distinguishable from genotypes collected in Utah. In field trials with naturally occurring herbivores and in lab experiments with Manduca sexta larvae, Arizona genotypes were damaged more and sustained greater herbivore growth than the Utah genotypes. When Arizona and Utah genotypes were grown in competition, Arizona genotypes produced significantly more seed capsules than the Utah neighbor did. Moreover, jasmonate elicitation, which dramatically increased TrypPI production in only the Utah genotypes, reduced lifetime fitness measures of the Utah genotypes more than of the Arizona genotypes, demonstrating that TrypPI production is correlated with a fitness cost. The loss of both a direct and an indirect defense suggests a functional linkage between these types of defense.Genotypes of the wild tobacco Nicotiana attenuata from different geographic regions in North America vary considerably in the level of constitutive and inducible trypsin protease inhibitors (TrypPIs), a potent direct defense, as well as in the production of herbivore-induced volatiles that function as indirect defense. Genotypes collected from Arizona were found to lack the ability to produce TrypPIs at a transcriptional level, had decreased volatile production, but exhibited nicotine and growth responses that were not distinguishable from genotypes collected in Utah. In field trials with naturally occurring herbivores and in lab experiments with Manduca sexta larvae, Arizona genotypes were damaged more and sustained greater herbivore growth than the Utah genotypes. When Arizona and Utah genotypes were grown in competition, Arizona genotypes produced significantly more seed capsules than the Utah neighbor did. Moreover, jasmonate elicitation, which dramatically increased TrypPI production in only the Utah genotypes, reduced lifetime fitness measures of the Utah genotypes more than of the Arizona genotypes, demonstrating that TrypPI production is correlated with a fitness cost. The loss of both a direct and an indirect defense suggests a functional linkage between these types of defense.Manduca sexta larvae, Arizona genotypes were damaged more and sustained greater herbivore growth than the Utah genotypes. When Arizona and Utah genotypes were grown in competition, Arizona genotypes produced significantly more seed capsules than the Utah neighbor did. Moreover, jasmonate elicitation, which dramatically increased TrypPI production in only the Utah genotypes, reduced lifetime fitness measures of the Utah genotypes more than of the Arizona genotypes, demonstrating that TrypPI production is correlated with a fitness cost. The loss of both a direct and an indirect defense suggests a functional linkage between these types of defense.