Transcriptomic analysis reveals the participation of NTRC in iron homeostasis throughout Arabidopsis development

NADPH-dependent thioredoxin reductase C (NTRC) plays a central role in redox regulation of chloroplast photosynthetic metabolism. Accordingly, Arabidopsis (Arabidopsis thaliana) NTRC null mutants show defective photosynthetic performance and growth inhibition. Remarkably, these mutants show almost wild type phenotype at the seedling stage, which raises the question of whether NTRC plays different functions throughout plant development. In this work, we have addressed this issue by performing transcriptome comparisons of Arabidopsis wild type and ntrc mutant lines at seedling and adult stages of development. In contrast with the high impact of NTRC on leaves from adult plants, the low transcriptomic differences in seedlings suggested a less-relevant function of NTRC at this stage of plant development. Notably, the ntrc mutant showed transcriptomic changes resembling the response to Fe excess throughout plant development, though this response was almost unique at the seedling stage. The lack of NTRC caused altered levels of Mn, Zn, Cu, S, P, K and Na, but no significant differences in the content of Fe, as compared with the wild type. Moreover, at the seedling stage, the lack of NTRC caused hypersensitivity to Fe deficit, but a protective effect in response to Fe excess, most likely due to lower ROS accumulation in the mutant seedlings. Our results reveal the different impact of NTRC throughout plant development and identify Fe homeostasis as a process highly affected by NTRC, most notably at the seedling stage. Two different transcriptomics experiments, adult and seedling stages, were carried out. For adult samples, eight-week-old short-day grown wild type and ntrc plants were randomly selected and young rosette leaves collected after 2 h of illumination at 125 µE m−2 s−1. Our experimental design consisted of three biological replicates for each genotype, each of them containing leaves from three individual plants. Wild type raw RNA-seq data from adult stage can be found in Gene Expression Omnibus identified with accession number GSE147793. For seedling samples, six-day-old continuous-light wild type and ntrc mutant grown in MS at 125 µE m−2 s−1 were collected. Our experimental design consisted of three biological replicates for each experimental condition.