Growth inhibition in an Arabidopsis L,L-diaminopimelate aminotransferase mutant is associated with both metabolic impairments and gibberellin deficiency

• Ano de defesa: 2021
• Autor(a) principal: Gouveia, Débora Gonçalves
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Arabidopsis; Aminoácidos; Lisina - Metabolismo; Giberelinas; Inibidores enzimáticos; Ecofisiologia Vegetal
• Link de acesso: https://locus.ufv.br//handle/123456789/29046; https://doi.org/10.47328/ufvbbt.2021.152

Lysine metabolism has been studied for almost 40 years and is clearly involved in plant response to stresses; however, questions regarding the importance of lysine remain open. Here, we investigated the metabolic and physiological impacts of exogenous application of gibberellic acid (GA 3 ) on the development of a mutant with drastically reduced activity of the lysine biosynthesis enzyme L,L-DAPAT (L,L-diaminopimelate aminotransferase). The DAPAT mutation culminated in reduced growth by impacting carbon and nitrogen metabolism, likely associated with apparent putative stress, even under optimal growth conditions. In general, the deficiency in lysine synthesis resulted in a lower content of reducing sugars and starch, especially at the end of the night. Furthermore, a substantial increase in amino acid levels was observed in dapat mutant plants, indicating a metabolic adjustment and consequent imbalance in carbon and nitrogen metabolisms, possibly as- sociated with continued growth in plants deficient in lysine biosynthesis. Mutant plants exhibited a differential expression of CPS, KS, and GA3ox genes, involved in the biosyn- thesis of Gibberellins (GA). Notably, the DAPAT mutation did not eliminate the respon- siveness to exogenous GA application of this mutant, promoting partial recovery of the characteristic dwarf phenotype. Although GA 3 treatment does not seem to affect the met- abolic pattern of the mutant plants, it is possibly responsible for the C/N imbalance, evi- denced by the increased expression of the sugar-starvation marker gene DIN6. Taken together, the results obtained indicate that lysine metabolism is a key point in the balance and allocation of soluble and reserve carbohydrates, and highlight the importance of L,L- DAPAT in controlling growth, primary metabolism, and hormone regulation. Keywords: Amino acids. Lysine biosynthesis. L,L-diaminopimelate aminotransferase. Gibberellin. Metabolic reprogramming.