Effects of UV and Elevation on Flavonoid Production in Juvenile Landrace Maize Leaf Tissue

Many plant populations are locally adapted to conditions that vary across the landscape. At the maize center of diversity in Southern Mexico, maize landraces are locally adapted to the environments in which they grow. Maize from higher elevation zones has been selected under conditions of greater exposure to UV-B light compared to lower elevation landraces. This could be important as climate change urges farmers to plant varieties from warmer, lower climes at higher elevations with higher UV-exposure. Our goal was to understand the biochemical mechanisms that may maintain high performance under local conditions, and how this biochemistry changes under novel conditions. In this study, we investigated UV-B protective flavonoids produced by maize landraces collected at three elevations (600 m, 1550 m, and 2050 m) and planted in common gardens at 1550 m and 2050 m in Chiapas, Mexico. Using high performance liquid chromatography (HPLC), we examined the presence and quantity of maize leaf flavonoids maysin, quercetin-3-glucoside (q-3-glucoside), and quercetin-3-rutinoside (q-3-rutinoside) produced across 12 maize collections from three elevations (i.e. maize types) and garden locations. Due to results from a previous gene expression study and the likely adaptive importance of UV-B protection, we hypothesized that highland maize may have higher production of certain UV-B protective compounds than lower elevational types, with all types inducing greater production in response to increases in UV-B. Our results demonstrate that increases in elevation increased flavonoid production. This response was similar across maize types from different elevations, although highland types seemed to have a greater induced response. These results may have implications for maize production with climate change since moving of crop populations to higher elevations to address warming may be disrupted by differential UV-B adaptation. Future work could investigate the fitness effects on plants that employ these different flavonoid pathways under higher and lower UV-B conditions to better understand desired chemotypes and their biological consequences.ECOSUROSUA one-year embargo was granted for this item.Academic Major: Evolution and Ecolog