Physiological responses of Eucalyptus globulus and E. grandis to high concentration of CO2 and temperature variations, identified by metabolomic and transcriptomic analyses

Resumo

Perennial plant species are constantly challenged by changes in their environment and to survive these unstable conditions, they developed anatomical, cellular and molecular mechanisms. Extremes of temperature are among the stresses that limit the geographical distribution and seasonal growth of various plants, affecting the quality and productivity in crops and forest plantations. However, climate models have indicated not only changes in global temperature, but also the amount of carbon dioxide (CO2) in the atmosphere. Several studies have shown that the cultivation of woody plants in CO2-rich atmosphere results in higher increases of biomass. However, growth under this condition is less pronounced when individuals are subjected to natural field conditions where there is competition for other resources, indicating the existence of a complex network of interactions between environmental factors and atmospheric CO2 concentration. Cellulose and lignin are the main polymers in plants. Eucalyptus is the largest source of cellulose in the world and lignin is a problem in the process of paper making, although it plays an important role in plants providing the support for cellulose micro fibrils in the cell walls. The eucalyptus is the forest crop of greater significance in Brazil, the world's largest producer of cellulose, and the cellulose industry is responsible for generating over 150 thousand jobs in the country. The objective of this proposal is to study the combined effect [low and high] temperature variation and increased levels of CO2 in the atmosphere has on the species Eucalyptus grandis and E. globulus. The second species grows better at lower temperatures and have impaired growth at higher temperatures. Its wood is of excellent quality, presenting high-yield pulp. Transcriptomic and metabolomics are proposed to assess this interaction. (AU)