Analysis of secondary metabolism and total chlorophyll content provides new insights into the role of A-tocopherol for wild type and VTE4 mutant Arabidopsis thaliana under different abiotic stresses

Plants experience different abiotic stresses under natural conditions including salinity, water deficit, low temperature and high light. Once plants are exposed to these stresses they might have a variety of responses physiologically and biochemically. In this study, we test this hypothesis in wild type Col-0 and vte4 mutant of Arabidopsis thaliana by measuring major secondary metabolites alongside with total chlorophyll content under different abiotic stresses namely salt stress, water stress and prolonged water deficiency. These stresses were imposed to the plants in separate experiments in which each treatment was replicated three times in a complete randomized design with factorial arrangement. It was concluded that under all abiotic stresses wild type Col-0 Arabidopsis plants showed stronger performance in terms of all major metabolites compared to vte4 mutant. ?-tocopherol deficiency in vte4 mutant plants led to lower accumulation of proline, total protein and total amino acids as well as starch and total sugars in comparison with wild type A. thaliana. Furthermore, all five secondary metabolites obtained the highest value under 100mM NaCl concentration (Salt stress), under 50% of field capacity (water stress) and under 8 days of water withholding (prolonged water deficiency). Wild type Col-0 resulted in higher level of total chlorophyll content under all abiotic stresses compared to mutant plants. Therefore, our results suggested that the loss of ?-tocopherol in vte4 mutant A.thaliana under different abiotic stresses affected the efficiency and the stability of central metabolism and photosynthetic apparatus.