AUTHOR=Wang Huifang , Han Xiaofan , Fu Xiaofeng , Sun Xinling , Chen Hailong , Wei Xirui , Cui Shubin , Liu Yiguo , Guo Weiwei , Li Ximei , Xing Jiewen , Zhang Yumei 

TITLE=Overexpression of TaLBD16-4D alters plant architecture and heading date in transgenic wheat

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.911993

DOI=10.3389/fpls.2022.911993

ISSN=1664-462X

ABSTRACT=<p>Lateral organ boundaries domain (LBD) proteins, a class of plant-specific transcription factors with a special domain of lateral organ boundaries (LOB), play essential roles in plant growth and development. However, there is little known about the functions of these genes in wheat to date. Our previous study demonstrated that <italic>TaLBD16-4D</italic> is conducive to increasing lateral root number in wheat. In the present work, we further examined important agronomical traits of the aerial part of transgenic wheat overexpressing <italic>TaLBD16-4D.</italic> Interestingly, it was revealed that overexpressing <italic>TaLBD16-4D</italic> could lead to early heading and multiple alterations of plant architecture, including decreased plant height, increased flag leaf size and stem diameter, reduced spike length and tillering number, improved spike density and grain width, and decreased grain length. Moreover, auxin-responsive experiments demonstrated that the expression of <italic>TaLBD16-4D</italic> in wild-type (WT) wheat plants showed a significant upregulation through 2,4-D treatment. <italic>TaLBD16-4D</italic>-overexpression lines displayed a hyposensitivity to 2,4-D treatment and reduced shoot gravitropic response. The expressions of a set of auxin-responsive genes were markedly different between WT and transgenic plants. In addition, overexpressing <italic>TaLBD16-4D</italic> affected the transcript levels of flowering-related genes (<italic>TaGI</italic>, <italic>TaCO1</italic>, <italic>TaHd1</italic>, <italic>TaVRN1</italic>, <italic>TaVRN2</italic>, and <italic>TaFT1</italic>). Notably, the expression of <italic>TaGI</italic>, <italic>TaCO1</italic>, <italic>TaHd1</italic>, <italic>TaVRN1</italic>, and <italic>TaFT1</italic> displayed significant upregulation under IAA treatment. Collectively, our observations indicated that overexpressing <italic>TaLBD16-4D</italic> could affect aerial architecture and heading time possibly though participating in the auxin pathway.</p>