On the role of central metabolism for the differential aluminum tolerance in three Arabidopsis thaliana ecotypes

• Ano de defesa: 2019
• Autor(a) principal: Lima, Italo Antunes Pereira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Arabidopsis - Efeito do alumínio; Metabólitos; Hidroponia; Toxicidade; Fisiologia Vegetal
• Link de acesso: https://locus.ufv.br//handle/123456789/27690

Aluminum (Al) toxicity is for long known to promote severe impairments to the production of many crops in acid soils. In order to overcome toxicity, Al resistance genes have been characterized in different plant species and are involved in two main mechanisms: (i) tolerance, regarding the Al detoxification within the plant cell and (ii) exclusion, which involves Al complexation in the rhizosphere by releasing of organic acids (OAs). Plants using the Al-induced OA exudation as the main mechanism might spend valuable carbon commodities during this process. Therefore, the OA exudation must be tightly regulated and closely related to the carbon metabolism. In this study, growth and yield parameters were used to compare the response of three Arabidopsis ecotypes namely Columbia-0 (Col-0), Wassilewkija (Ws), and Landsberg erecta (Ler), under Al stress, which was correlated with expression of Al-responsive genes. Further, a detailed metabolic characterization was also performed in 28-day- old plants grown in hydroponic system. The so-called Al-sensitive ecotypes, Col-0 and Ws, presenting higher yield and growth under control conditions, exhibited stronger reductions in these parameters under long-term Al exposure. Ler, classified as the most capable in dealing with Al stress, showed relative smaller reductions comparing control and Al-stress conditions. All the ecotypes presented high expression of the well-known Al-resistance gene AtALMT1. Col-0 and Ws plants under Al stress increased leaf fructose and starch contents, suggesting a low carbon use efficiency (CUE). Similarly, higher increases in amino acids, carbohydrates and organic acids levels occurred in both shoot and roots tissues of Col-0 and Ws plants, but not of Ler. Altogether, our results suggest that higher capacity of using and translocate reduced carbon molecules seems to be crucial to Arabidopsis overcome Al stress. In addition, lower expenses in carbon molecules might be linked to a higher capacity to deal with Al stress in long-term experiments. Overall, our results support a tight relationship between primary metabolism and Al stress responses. The results obtained are discussed within the context of current models of Al resistance mechanism providing novel insights on the influence of Al stress on plant growth and primary metabolism in leaves and shoots.