Differential preference of Capsicum spp. cultivars by Aphis gossypii is conferred by variation in volatile semiochemistry

• Published in: Euphytica 2011-02, Vol.177 (3), p.299-307
• Main Authors: da Costa, João Gomes, Pires, Edjane Vieira, Riffel, Alessandro, Birkett, Michael A, Bleicher, Ervino, Sant'Ana, Antônio Euzébio Goulart
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Animal behavior; Aphididae; Aphis gossypii; Bioassays; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Capsicum; Cultivars; Fundamental and applied biological sciences. Psychology; Gas chromatography; genetic variation; Genetics and breeding of economic plants; Green belts; host plants; host preferences; insect behavior; insect pests; Insects; Life Sciences; literature reviews; Mass spectrometry; olfactometry; Organic compounds; pest resistance; Plant breeding: fundamental aspects and methodology; Plant Genetics and Genomics; Plant Pathology; plant pests; Plant Physiology; Plant resistance; Plant Sciences; Review; Selective breeding; semiochemicals; sweet peppers; Varietal selection. Specialized plant breeding, plant breeding aims; Vegetables; VOCs; volatile compounds; Volatile organic compounds
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1007/s10681-010-0250-8

The aim of this study was to demonstrate that Capsicum spp. cultivars are differentially preferred by the cotton aphid, Aphis gossypii, and to investigate the role of volatile semiochemicals in conferring differences in host preferences. Two preference assays were conducted in 2008 under greenhouse conditions. Fourteen different commercially available cultivars were grown in cages protected by an anti-aphid net, and were infested 60 days after planting, through the release of ten adult female A. gossypii per plant. The results showed that after a five-day infestation period, statistically significant differences in the mean number of A. gossypii between cultivars were observed, with Sweet Pepper Hybrid Green Belt (SPHGB) being one of the cultivars with the lowest number of A. gossypii per plant. To test the hypothesis that the preference of cultivars was associated with release of volatile, Capsicum spp-derived semiochemicals, olfactometer behavior bioassays were conducted with A. gossypii, using volatile organic compounds (VOCs) collected from non-preferred SPHGB and preferred SPAB cultivars. A. gossypii was significantly repelled only by the VOCs of infested SPHGB. Furthermore, coupled gas chromatography-mass spectrometry (GC-MS) analysis of VOCs released by plants prior to, and after, A. gossypii infestation, revealed that the non-preferred SPHGB cultivar released nine additional compounds after infestation, including 6-methyl-5-hepten-2-one, a known plant defense semiochemical involved in plant--aphid interactions. These data suggest that non-preferred cultivars releasing this semiochemical have the potential to be used in breeding programs aimed at producing A. gossypii-resistant Capsicum spp. cultivars.