AUTHOR=Wu Jun , Wu Qiuhong , Bo Zhongjian , Zhu Xuli , Zhang Junhui , Li Qingying , Kong Wenqing 

TITLE=Comprehensive Effects of Flowering Locus T-Mediated Stem Growth in Tobacco

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.922919

DOI=10.3389/fpls.2022.922919

ISSN=1664-462X

ABSTRACT=<p>In flowering plants, <italic>Flowering locus T</italic> (<italic>FT</italic>) 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 <italic>FT</italic> promotes flowering is currently clearly understood, comprehensive effects of the <italic>FT</italic> 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 <italic>FT</italic> gene. In this study, the <italic>Jatropha curcas</italic> L. <italic>FT</italic> gene was overexpressed in tobacco (JcFT<sup>OE</sup>) in order to discover multiple aspects and related mechanisms of how the <italic>FT</italic> gene affects plant development. In JcFT<sup>OE</sup> plants, root, stem, and leaf development was strongly affected. Stem tissues were selected for further transcriptome analysis. In JcFT<sup>OE</sup> plants, stem growth was affected because of changes in the nucleus, cytoplasm, and cell wall. In the nucleus of JcFT<sup>OE</sup> 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<sup>OE</sup> plants, which decreased the thickness and height of tobacco stems. In the cell wall of JcFT<sup>OE</sup> 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<sup>OE</sup> plants, the primary effects were on biogenesis of ribonucleoprotein complexes, photosynthesis, carbohydrate biosynthesis, and the cytoskeleton. In addition, in the cytoplasm of JcFT<sup>OE</sup> plants, there were changes in certain factors of the core oscillator, expression of many light-harvesting chlorophyll <italic>a</italic>/<italic>b</italic> binding proteins was down-regulated, and expression of <italic>fructose 1,6-bisphosphatase</italic> genes was up-regulated to increase starch content in tobacco stems. Changes in the xylem and phloem of JcFT<sup>OE</sup> plants were also identified, and in particular, xylem development was affected by significant increases in expression of <italic>irregular xylem</italic> genes.</p>