Biochemical and physiological characterization of two isoforms of mitochondrial ADP/ATP carriers in Arabidopsis

• Ano de defesa: 2025
• Autor(a) principal: Cazor Curilef, Crystal Liz
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Mitocôndria; Respiração; Metabolismo; Difosfato de adenosina; Trifosfato de adenosina; Fisiologia Vegetal
• Link de acesso: https://locus.ufv.br/handle/123456789/34916; https://doi.org/10.47328/ufvbbt.2025.356

Mitochondria are essential for respiration and energy production in eukaryotic cells, where ATP drives numerous energy-dependent processes. The exchange of adenylates(AMP, ADP, ATP) between the mitochondrial matrix and cytosol is facilitated by mitochondrial carrier proteins (MCFs), including ADP/ATP carriers (AACs). In Arabidopsis thaliana, three genes encode AAC carriers: AAC1, AAC2, and AAC3. While AAC1 has been linked to plant respiration and growth, the functions of AAC2 and AAC3 are poorly understood. This study aimed to elucidate the metabolic roles of AAC1 and AAC2 by characterizing single and double mutant lines with low expression of these carriers. Four A. thaliana genotypes were studied: wild type (WT), low AAC1 expression (aac1), low AAC2 expression (aac2), and the double mutant (aac1:aac2). Plants were exposed to short-day photoperiod for metabolic and biometric analyses and long-day for evaluation of reproductive traits. Under short-day condition, mutant plants displayed reduced root growth and respiratory activity, alongside an accumulation of sugars, total free amino acids, and organic acids. These findings suggest disruptions in the TCA cycle and unbalanced carbon-nitrogen metabolisms. Although photosynthetic parameters remained unchanged, pigment depletion and altered chlorophyll ratios indicated possible photoprotective responses. Under long-day conditions, alterations in reproductive traits were observed, including increased branching and seed production, hinting at a compensatory mechanism to maintain reproduction under energy deficiency. These results underscore the critical roles of AAC1 and AAC2 in energy metabolism, root development, and reproductive plasticity, offering insights into how plants adapt to mitochondrial dysfunction. Keywords: Mitochondria; Respiration; Adenylates carriers; Metabolism