posted on 2015-11-17, 00:00authored bySanghamitra Majumdar, Igor C. Almeida, Emma A. Arigi, Hyungwon Choi, Nathan
C. VerBerkmoes, Jesica Trujillo-Reyes, Juan P. Flores-Margez, Jason C. White, Jose R. Peralta-Videa, Jorge L. Gardea-Torresdey
The
rapidly growing literature on the response of edible plants
to nanoceria has provided evidence of its uptake and bioaccumulation,
which delineates a possible route of entry into the food chain. However,
little is known about how the residing organic matter in soil may
affect the bioavailability and resulting impacts of nanoceria on plants.
Here, we examined the effect of nanoceria exposure (62.5–500
mg/kg) on kidney bean (Phaseolus vulgaris) productivity
and seed quality as a function of soil organic matter content. Cerium
accumulation in the seeds produced from plants in organic matter enriched
soil showed a dose-dependent increase, unlike in low organic matter
soil treatments. Seeds obtained upon nanoceria exposure in soils with
higher organic matter were more susceptible to changes in nutrient
quality. A quantitative proteomic analysis of the seeds produced upon
nanoceria exposure provided evidence for upregulation of stress-related
proteins at 62.5 and 125 mg/kg nanoceria treatments. Although the
plants did not exhibit overt toxicity, the major seed proteins primarily
associated with nutrient storage (phaseolin) and carbohydrate metabolism
(lectins) were significantly down-regulated in a dose dependent manner
upon nanoceria exposure. This study thus suggests that nanoceria exposures
may negatively affect the nutritional quality of kidney beans at the
cellular and molecular level. More confirmatory studies with nanoceria
along different species using alternative and orthogonal “omic”
tools are currently under active investigation, which will enable
the identification of biomarkers of exposure and susceptibility.