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ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #371860

Research Project: Optimizing Photosynthesis for Global Change and Improved Yield

Location: Global Change and Photosynthesis Research

Title: Age-dependent increase in a-tocopherol and phytosterols in maize leaves exposed to elevated ozone pollution

item WEDOW, JESSICA - University Of Illinois
item BURROUGHS, CHARLES - University Of Illinois
item RIOS ACOSTA, LORENA - University Of Illinois
item LEAKEY, ANDREW D B - University Of Illinois
item Ainsworth, Elizabeth - Lisa

Submitted to: Plant Direct
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2021
Publication Date: 2/10/2021
Citation: Wedow, J.M., Burroughs, C., Rios Acosta, L., Leakey, A.D.B., Ainsworth, E.A. 2021. Age-dependent increase in a-tocopherol and phytosterols in maize leaves exposed to elevated ozone pollution. Plant Direct. 5(2). Article e00307.

Interpretive Summary: Ground-level ozone is a damaging air pollutant that reduces crop yields around the world. The metabolic responses to increasing ozone pollution have not been widely studied in crops, especially in crops grown in the field. We used a unique field facility to grown two classic maize inbred lines (B73 and Mo17) and their hybrid cross (B73 x Mo17) in the field at elevated ozone, and to study the response of leaf metabolites. We discovered that the hybrid line was more sensitive to ozone stress than the inbred lines. Two key metabolic changes in the hybrid at elevated ozone included increased sterol production, which may help stabilize membranes, and increased alpha-tocopherol, which could quench damaging reactive oxygen species in chloroplasts.

Technical Abstract: Tropospheric ozone is a major air pollutant that significantly damages crop production around the world. Crop metabolic responses to rising chronic ozone stress have not been well-studied in the field, especially in C4 crops. In this study, we investigated the metabolomic profile of leaves from two diverse maize (Zea mays) inbred lines and the hybrid cross during exposure to season-long elevated ozone (~100 nL L-1) in the field using free air concentration enrichment (FACE). The hybrid line, B73 x Mo17, showed an acceleration of chlorophyll loss under elevated ozone accompanied by a significant change in the metabolite profile. In contrast, the metabolite profile, although significantly different between the two inbred lines (B73 and Mo17), was not different in ambient and elevated ozone treatments. Phytosterols and alpha-tocopherol levels increased in B73 x Mo17 leaves as they aged, and to a significantly greater degree in elevated ozone stress. Untargeted metabolomic profiling revealed that inbred and hybrid lines of maize differ in ozone response and metabolic responses provide stabilization of membranes and chloroplast reactive oxygen species quenching in the responsive hybrid line.