AUTHOR=Guo Xiaotong , Li Yue , Li Ningning , Li Guolong , Sun Yaqing , Zhang Shaoying 

TITLE=BvCPD promotes parenchyma cell and vascular bundle development in sugar beet (Beta vulgaris L.) taproot

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1271329

DOI=10.3389/fpls.2023.1271329

ISSN=1664-462X

ABSTRACT=<p>Constitutive photomorpogenic dwarf (<italic>CPD</italic>) is a pivotal enzyme gene for brassinolide (BR) synthesis and plays an important role in plant growth, including increasing plant biomass and plant height, elongating cells, and promoting xylem differentiation. However, little is known about the function of the <italic>CPD</italic> gene in sugar beet. In the current study, we isolated <italic>CPD</italic> from <italic>Beta vulgaris</italic> L. (<italic>BvCPD</italic>), which encodes protein localized in the nucleus, cell membrane, and cell wall. <italic>BvCPD</italic> was strongly expressed in parenchyma cells and vascular bundles. The transgenic sugar beet overexpressing <italic>BvCPD</italic> exhibited larger diameter than that of the wild type (WT), which mainly owing to the increased number and size of parenchyma cells, the enlarged lumen and area of vessel in the xylem. Additionally, overexpression of <italic>BvCPD</italic> increased the synthesis of endogenous BR, causing changes in the content of endogenous auxin (IAA) and gibberellin (GA) and accumulation of cellulose and lignin in cambium 1–4 rings of the taproot. These results suggest that <italic>BvCPD</italic> can promote the biosynthesis of endogenous BR, improve cell wall components, promote the development of parenchyma cells and vascular bundle, thereby playing an important role in promoting the growth and development of sugar beet taproot.</p>