INVESTIGADORES
PRADO carolina Del Valle
capítulos de libros
Título:
HEAVY METALS. FUNCTIONAL AND METABOLIC INTERACTIONS BETWEEN CARBOHYDRATES AND SECONDARY METABOLITES IN PLANTS. A REVIEW
Autor/es:
CAROLINA PRADO, GRISELDA PODAZZA, EDUARDO PAGANO, FERNANDO E. PRADO, MARIANA ROSA
Libro:
Hazardous Materials: Tipes, Risks and Control
Editorial:
NOVA Publisher
Referencias:
Lugar: Nueva York; Año: 2011; p. 1 - 53
Resumen:
During the evolution, plants have repeatedly adapted to their respective niche, which is reflected in changes of their metabolism and plant body in response to environmental stresses and/or pathogen and predator attacks. Among environmental stresses, heavy metals produce a pleyade of effects on plants. Many heavy metals at low concentrations play important roles in plant function and metabolism but at high concentrations, they become toxic for plants. Although the ability to acquire both the tolerance against heavy metals and accumulation capacity to very high concentrations has evolved both independently and together in a number of different plant species, many metabolic responses of plants still remain unknown. Plants utilize the sunlight for the synthesis of carbohydrates, which serve for multiple purposes. Soluble carbohydrates, especially sucrose, glucose, and fructose, play a central role as source of energy, building blocks, and protective and/or defensive compounds in the plant structure and metabolism at the cellular and whole-organism levels. They also act as metabolite signalling molecules that activate specific transduction pathways, thus resulting in important modifications of the gene expression and proteomic patterns. Moreover, under heavy metals exposure soluble sugars are also involved, and they are related to important changes in the balance of reactive oxygen species and, conversely, with the mitochondrial respiration and/or photosynthesis process, as well as with anti-oxidative events, such as the oxidative pentose-phosphate pathway and carotenoid biosynthesis. Then, understanding the transport and localization of heavy metals into plant cells, as well as involvement of carbohydrates in the metal tolerance and/or detoxification processes are critical for understanding the heavy metal metabolic pathways, as well as their bioavailability to animals and humans. Subsequently, understanding relationships between primary and secondary metabolisms will be able to be applied to know the responses of plant defenses to pathogen and herbivore attacks. From the available data, it has become clear that changes in the content of primary and secondary metabolites bear functional significance in the context of metal stress tolerance. Therefore, this chapter compiles the information available on selected stress metabolite accumulation under conditions of heavy metal exposure and examines the functional significance of responses. Emphasis has been given to sucrose, sucrose-derived hexoses and sucrose-hydrolyzing enzymes, as well as to phenylpropanoid-derived compounds, that seem to possess different but specific functions in heavy metal-stressed plants. This review has been written with the intent that plant researchers gain familiarity with soluble carbohydrates, secondary metabolites and heavy metals. Also these data will be helpful for better understanding of the mechanisms of plant adaptation to heavy metal stress at the metabolite level.