Metabolic changes associated with dark-induced leaf senescence in Arabidopsis nadk2 mutants

• Published in: Plant signaling & behavior 2023-12, Vol.18 (1), p.2215618-2215618
• Main Authors: chaomurilege, Miyagi, Atsuko, Ishikawa, Toshiki, Yamaguchi, Masatoshi, Murayama, Hideki, Kawai-Yamada, Maki
• Format: Article
• Language: English
• Subjects: Arabidopsis; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; CE-MS; metabolites; NAD - metabolism; NAD kinase; NAD(P)(H); NADP - metabolism; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Senescence; Research Paper
• ISSN: 1559-2316; 1559-2324; 1559-2324
• DOI: 10.1080/15592324.2023.2215618

Arabidopsis NADK2 (NAD kinase 2) is a chloroplast-localized enzyme involved in NADP + synthesis, which acts as the final electron acceptor in the photosynthetic electron transfer chain. The NADK2-deficient mutant (nadk2) was used to analyze the effect of NAD(P)(H) unbalance in the dark-induced leaf senescence. During senescence, WT plants and nadk2 mutants showed a similar reduction in chlorophyll content. NAD(P)(H) quantification showed that the amount of total NAD(P)(H) decreased on the day 7 in WT but on the day 3 in nadk2. The phosphorylation ratio (i.e. NADP(H)/NAD(H)) decreased on day 1 in WT. In contrast, the nadk2 showed lower phosphorylation ratio at 0 day and no change throughout the aging process. Metabolome analysis showed that the metabolic profiles of both WT plants and nadk2 mutants subjected to dark-induced senescence adopted similar patterns as the senescence progressed. However, the changes in individual metabolites in the nadk2 mutants were different from those of the WT during dark-induced senescence.