PhD Student Hungarian University of Agriculture and Life Sciences Budapest, Budapest, Hungary
Body of Abstract: Cadmium (Cd) poses a significant threat to crop production and food safety as a hazardous heavy metal stressor. Cd exposure not only causes visible symptoms like chlorosis and growth inhibition but also disrupts crucial physiological and biochemical processes such as photosynthesis, and induces reactive oxygen species (ROS) accumulation, signaling pathways, and protective compound synthesis. Light is crucial to plant development and stress responses, although its effect on Cd stress is poorly understood. We hypothesized that light quality can modulate plant adaptation to Cd stress at the metabolite and gene expression levels. To investigate this, wheat plants were grown in pots on the hydroponic solution for 14 days under controlled conditions in a plant growth chamber (20/18˚ C 8/16-h light/dark periodicity; PPFD: 250 μmol m-2 s-1) under white (W; spectral composition: 32.32% blue, 45.7% green, 20.7% red and 1.25% far-red) or blue (B; spectral composition: 82.14% blue, 1% green, 16.7% red and 0.17% far-red) light conditions. 14-day-old plants were exposed to 50 µM Cd(NO3)2 stress. After seven days of Cd treatment samples were collected for further analyses. Compared to white light, blue light decreased Cd sensitivity, reducing Cd content, lipid peroxidation, and hydrogen peroxide levels. Blue light also induced antioxidant enzymes, preventing further increases upon Cd treatment. In contrast, Cd stress under white light led to higher enzyme activities, particularly in roots. Metabolomic analyses revealed changes in polyamine, thiol, phytochelatin, and hormone contents after exposure to different light compositions and/or Cd stress. Gene expression analyses were performed to elucidate the underlying molecular mechanisms. Our findings demonstrate that light quality influences plant adaptation to Cd stress at the metabolite and gene expression levels. These findings improve our understanding of plant responses to heavy metal stress and highlight the relevance of light conditions in moderating Cd's impacts on crops and food safety.