2026-06-03T16:06:23Zhttps://riuma.uma.es/rest/oai/request

oai:riuma.uma.es:10630/458712026-03-03T00:47:05Zcom_10630_2254col_10630_37953

Arabidopsis lines with modified ascorbate concentrations reveal a link between ascorbate and auxin biosynthesis Fenech, Mario Zulian, Viviane Moya-Cuevas, José arnaud, Dominique Morilla, Ian Smirnoff, Nicolas Botella-Mesa, Miguel Ángel Stepanova, Anna N. Alonso, José M. Martín-Pizarro, Carmen Amorim-Silva, Vitor Arabidopsis Ascorbate is the most abundant water-soluble antioxidant in plants and an essential molecule for normal plant development. Although present in all green plants, ascorbate concentrations vary among plant species and tissues. While ascorbate accumulation is a trait of nutritional, and therefore, agronomical interest, the impact of different concentrations on cellular homeostasis remains elusive. To shed light on this question, we compared Arabidopsis (Arabidopsis thaliana) lines with very low (vtc2 mutant, 20% of wild-type (WT) levels), low (vtc4 mutant, 65% of WT levels), and high (vtc2/OE-VTC2, 165% of WT levels) ascorbate concentration in 4-wk-old rosette leaves. An 80% reduction of ascorbate increased the expression of genes implicated in defense against pathogens but repressed genes associated with abiotic stress responses. Unexpectedly, lines with increased (165% of WT) and decreased (65% of WT) ascorbate levels shared 85% of induced transcription factors and the gene ontology terms associated with their transcriptional programs. We identified TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (TAA1), a gene encoding the enzyme that catalyzes the first step of auxin biosynthesis, among the group of genes whose expression was positively correlated with ascorbate content. Using a combination of genetic and pharmacological approaches in fluorescent and histochemical reporter lines for auxin biosynthesis and signaling activity, we revealed that TAA1- and TAA1 RELATED 2 (TAR2)- mediated auxin biosynthesis is necessary for plants to cope with increased ascorbate concentration in a light-dependent manner, revealing a layer of complexity in the regulatory landscape of redox homeostasis. 2026-03-02T11:33:55Z 2026 2026-02 journal article Fenech M, Zulian V, Moya-Cuevas J, Arnaud D, Morilla I, Smirnoff N, Botella MA, Stepanova AN, Alonso JM, Martin-Pizarro C, Amorim-Silva V. Arabidopsis lines with modified ascorbate concentrations reveal a link between ascorbate and auxin biosynthesis. Plant Physiol. 2026 Feb 6;200(2):kiaf667. doi: 10.1093/plphys/kiaf667. PMID: 41431746. Copy https://hdl.handle.net/10630/45871 10.1093/plphys/kiaf667 eng http://creativecommons.org/licenses/by/4.0/ open access Attribution 4.0 International Oxford University Press