Although Selenium (Se) stress is relatively well known for causing growth inhibition, its effects on primary metabolism remain rather unclear. Here, we characterized both the modulation of the expression of specific genes and the metabolic adjustments in Arabidopsis thaliana in response to changes in Se level in the soil. Se treatment culminated with strong inhibition of both shoot and root growth. Notably, growth inhibition in Se-treated plants was associated with an incomplete mobilization of starch during the night. Minor changes in amino acids levels were observed in shoots and roots of plants treated with Se whereas the pool size of tricarboxylic acid (TCA) cycle intermediates in root was not altered in response to Se. By contrast, decreased levels of organic acids involved in the first part of the TCA cycle were observed in shoots of Se-treated plants. Furthermore, decreased expression levels of expansins and endotransglucosylases/endohydrolases (XHTs) genes were observed after Se treatment, coupled with a significant decrease in the levels of essential elements. Collectively, our results revealed an exquisite interaction between energy metabolism and Se-mediated control of growth in Arabidopsis thaliana to coordinate cell wall extension, starch turnover and the levels of a few essential nutrients.

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Gibberellins (GAs) play a crucial role in modulating developmental processes throughout the plant life cycle. Among the processes in which GAs are involved, they are of significance during the transition and maintenance of the reproductive meristem, as well as in allowing the floral organs development. GAs are also able to regulate, alongside with auxin and cytokinin, the initial processes of fruit development, most likely because they are responsible for both division and cell expansion. It is unknown whether fluctuations in the endogenous content of GAs impact fruit development and metabolism during ripening. To investigate these questions, tomato mutant plants deficient in GAs biosynthesis (gib3, moderately deficient; gib2, intermediate deficiency and gib1, extremely deficient in GA) were used. Notably, gib2 and gib1 mutants were characterized by a complete interruption of their reproductive development at the floral bud level. Although gib3 plants displayed a slightly delay in fruit development, at the end of fruit ripening both WT and gib3 fruits were highly similar. Little differences were found between WT and gib3 mutant plants during floral development and total fruit yield. We demonstrated that reduced GAs in gib3 mutant did not promote morphological modifications in fruits and relatively few metabolic changes were observed between genotypes during fruit ripening. Overall, typical metabolic changes, including increments in amino acids and soluble sugars coupled with reductions in starch, were observed during ripening. Collectively, we demonstrate that GAs plays a significant role on change vegetative to reproductive stage, as well as on the binging of set fruit.