Comprehensive Effects of T-Mediated Stem Growth in Tobacco.

In flowering plants, () encodes a major florigen. It is a key flowering hormone in controlling flowering time and has a wide range of effects on plant development. Although the mechanism by which promotes flowering is currently clearly understood, comprehensive effects of the gene on plant growth have not been evaluated. Therefore, the effects of FT on vegetative growth need to be explored for a complete understanding of the molecular functions of the gene. In this study, the L. gene was overexpressed in tobacco (JcFT) in order to discover multiple aspects and related mechanisms of how the gene affects plant development. In JcFT plants, root, stem, and leaf development was strongly affected. Stem tissues were selected for further transcriptome analysis. In JcFT plants, stem growth was affected because of changes in the nucleus, cytoplasm, and cell wall. In the nucleus of JcFT plants, the primary effect was to weaken all aspects of DNA replication, which ultimately affected the cell cycle and cell division. The number of stem cells decreased significantly in JcFT plants, which decreased the thickness and height of tobacco stems. In the cell wall of JcFT plants, hemicellulose and cellulose contents increased, with the increase in hemicellulose associated with up-regulation of xylan synthase-related genes expression. In the cytoplasm of JcFT plants, the primary effects were on biogenesis of ribonucleoprotein complexes, photosynthesis, carbohydrate biosynthesis, and the cytoskeleton. In addition, in the cytoplasm of JcFT plants, there were changes in certain factors of the core oscillator, expression of many light-harvesting chlorophyll / binding proteins was down-regulated, and expression of genes was up-regulated to increase starch content in tobacco stems. Changes in the xylem and phloem of JcFT plants were also identified, and in particular, xylem development was affected by significant increases in expression of genes.