Ricerc@Sapienza

Arsenic (As) and cadmium (Cd) are very toxic and widespread environmental pollutants that endanger health to all the living organisms. They may enter into the food chain because they are easily absorbed by plant roots. These elements are able to induce deep changes in plants, often consisting in damages on their development, metabolism and productivity. The earliest and greatest damages occur in the root system, and cause inhibition of root growth and modifications of root architecture. Morphological, histological and developmental changes are frequently the plant response to abiotic stresses, and also occur after As and Cd exposure as result of very complex interactions among phytohormones, e.g., auxin and jasmonates, and stressors.
In this research the relation between jasmonates and auxin during the development of adventitious roots, and their lateral roots, under exposure to Cd and/or As will be investigated in rice seedlings, also using the cpm2 mutant blocked in jasmonic acid (JA) biosynthesis. To the aim, we will carry out morphological analysis on the root system of Nihonmasari (wt) and cpm2 mutant, exposed to Cd and/or As, in the presence or absence of exogenous methyl jasmonate (MeJA), the methyl ester of JA. Cadmium and As accumulation will be evaluated in the roots and shoots of the two genotypes exposed to As and/or Cd, as well as indole-3-acetic acid (IAA) and jasmonic acid (JA) endogenous levels. The expression levels of some jasmonate and auxin biosynthetic genes will be analyzed after treatment with the toxic elements. A histochemical analysis on OsDR5::GUS seedlings, exposed to As and/or Cd, combined or not with MeJA, will be carried out. Lastly, we will investigate the extent of lipid peroxidation, through the quantification of a decomposition product of polyunsaturated fatty acids, i.e. malondialdehyde (MDA), both in wt and cpm2 roots exposed to Cd and/or As.