Kariyat, Rupesh , andrew, Stephenson .
Volatile mediated indirect defense signaling is disrupted by inbreeding and genetic variation in Horsenettle (Solanum carolinense L).
Inbreeding is commonly observed in natural plant population with negative effects on fitness traits and susceptibility to herbivory. Herbivorous insects remove photosynthetic leaf area from plants thereby affecting fitness and also inducing defense responses such as the emission of herbivore induced volatile organic compounds (VOC) and subsequent attraction of predators and natural enemies. Although host plant genetic diversity and inbreeding are likely to influence induced plant chemistry, few studies have examined induced response phenotypes across different genetic backgrounds. This study was designed to examine whether genetic background (maternal family) and inbreeding affect qualitative and quantitative aspects of herbivore-induced VOCs; and whether these differences affect herbivores and their natural enemies under field conditions, using common horsenettle (Solanumcarolinense L.) as the study system. Our results suggest that breeding influences volatile emissions both quantitatively and qualitatively, and that genetic background (starting population) also influences emissions, with inbred plants emitting more volatiles when undamaged but less when damaged compared to the outbred plants.
The analysis of insect attraction in the field indicates that breeding, damage, and breeding x damage are all highly significant with damaged outbred plants with higher volatile emissions able to attract higher number of parasitoid hymenopterans and undamaged inbred plants with higher volatile emission attracting higher number of herbivorous coleopteran and dipteran insects. Our study takes a novel approach in tritrophic interactions because few studies have combined lab and field experiments as a means of investigating indirect plant defense signaling, focusing on the effects of inbreeding and genetic background (maternal family) influence the quantity and quality of VOC blends produced constitutively and in response to specialist herbivore feeding, and that inbreeding in particular plays a strong role in determining the attraction of herbivorous and predatory insects in the field, suggesting that inbreeding disrupts the indirect defense phenotype.
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Presentation Type: Oral Paper:Papers for Sections
Location: Forsyth Room/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 10:45 AM