AUTHOR=Xu Huaping , Xie Haicui , Wu Shengyong , Wang Zhenying , He Kanglai 

TITLE=Effects of Elevated CO2 and Increased N Fertilization on Plant Secondary Metabolites and Chewing Insect Fitness

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00739

DOI=10.3389/fpls.2019.00739

ISSN=1664-462X

ABSTRACT=<p>Elevated atmospheric CO<sub>2</sub> (eCO<sub>2</sub>) and increased nitrogen (N) fertilization significantly change the nutritional quality of plants and influence the growth and development of insects. However, little is known about plant metabolism and plant-insect interactions under eCO<sub>2</sub> and increased N fertilization, especially C<sub>4</sub> plants. Thus, the combined effects of eCO<sub>2</sub> and increased N fertilization on maize-<italic>Ostrinia furnacalis</italic> interactions were tested in this study. Our data demonstrated that both eCO<sub>2</sub> and increased N fertilization increased starch content, while increased N fertilization promoted the N content in maize. The combined effects of eCO<sub>2</sub> and increased N fertilization did not influence the total non-structural carbohydrates (TNC):N ratio in maize. The jasmonic acid level of maize was enhanced by increased N fertilization and <italic>O. furnacalis</italic> infestation. The total phenolics content and defensive enzyme activities of maize increased under eCO<sub>2</sub>, increased N fertilization and <italic>O. furnacalis</italic> infestation. Protective enzyme activities were enhanced, while digestive enzyme activities, mean relative growth rate, body mass and efficiency of conversion of ingested food decreased for <italic>O. furnacalis</italic> feeding on maize grown under eCO<sub>2</sub> and increased N fertilization. Therefore, eCO<sub>2</sub> and increased N fertilization increased starch and N accumulation, and did not influence the TNC:N ratio, however, eCO<sub>2</sub> and N promoted the resistance-related secondary metabolites (with or without <italic>O. furnacalis</italic> induced) of maize, which ultimately decreased the fitness of <italic>O. furnacalis</italic> to the host. These results will help to better understand the metabolic mechanisms of plants and the plant-insect interaction under eCO<sub>2</sub> and increased N fertilization in the context of future climate change scenarios.</p>