Effects of elevated CO2 and soil water content on phytohormone transcript induction in Glycine max after Popillia japonica feeding

• Published in: Arthropod-plant interactions 2012-09, Vol.6 (3), p.439-447
• Main Authors: Casteel, Clare L., Niziolek, Olivia K., Leakey, Andrew D. B., Berenbaum, May R., DeLucia, Evan H.
• Format: Article
• Language: English
• Subjects: Behavioral Sciences; Biomedical and Life Sciences; Biosynthesis; Carbon dioxide; Climate change; Drought; Ecology; Entomology; Global climate; Glycine max; Herbivory; Insects; Invasive insects; Invertebrates; Jasmonic acid; Leaves; Life Sciences; Moisture content; Nutritive value; Original Paper; Pests; Phytohormones; Plant hormones; Plant Pathology; Plant Sciences; Plant tissues; Popillia japonica; Salicylic acid; Signaling; Soil water; Soils; Soybeans; Sugar; Transcription; Water content
• ISSN: 1872-8855; 1872-8847
• DOI: 10.1007/s11829-012-9195-2

Plants will experience increased atmospheric CO 2 and drought in the future, possibly altering plant–insect dynamics. To investigate the combined effects of these components of global change on plant–insect interactions, three major hormone signaling pathways [jasmonic acid (JA), salicylic acid (SA), and ethylene (ET)] and related defenses were examined in undamaged soybean ( Glycine max ) leaves and after Japanese beetle ( Popillia japonica ) feeding; plants were grown under elevated CO 2 and reduced soil water both independently and simultaneously. Nutritional quality and Japanese beetle preference for leaf tissue grown under these different conditions also were determined. Elevated CO 2 increased the concentration of leaf sugars and dampened JA signaling transcripts but increased the abundance of SA compared with plants grown in ambient CO 2 . A mild reduction in soil water content had no effect on leaf sugars but stimulated the induction of transcripts related to JA and ET biosynthesis after herbivory. When applied in combination, elevated CO 2 and reduced soil water content suppressed the expression of transcripts related to JA and ET gene transcription. Exposure to elevated CO 2 alone increased susceptibility of soybean to beetle damage. However, exposure to elevated CO 2 in combination with reduced soil water content negated the impact of elevated CO 2 , leaving susceptibility unchanged. Predicting future crop resistance to pests must take into account interactions among individual components of global climate change.