AUTHOR=Tian Dongdong , Tang Jingwen , Luo Liwen , Zhang Zhe , Du Kebing , Larkin Robert M. , Shi Xueping , Zheng Bo 

TITLE=Influence of Switchgrass TDIF-like Genes on Arabidopsis Vascular Development

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.737219

DOI=10.3389/fpls.2021.737219

ISSN=1664-462X

ABSTRACT=<p>As a member of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (CLE) family, the dodecapeptide tracheary element differentiation inhibitory factor (TDIF) has a major impact on vascular development in plants. However, the influence of polymorphisms in the TDIF peptide motif on activity remains poorly understood. The model plant, <italic>Arabidopsis</italic> provides a fast and effective tool for assaying the activity of <italic>TDIF</italic> homologs. Five <italic>TDIF</italic> homologs from a group of 93 <italic>CLE</italic> genes in switchgrass (<italic>Panicum virgatum</italic>), a perennial biomass crop, named <italic>PvTDIF-like</italic> (<italic>PvTDIFL</italic>) genes were studied. The expression levels of <italic>PvTDIFL1, PvTDIFL3</italic><sup><italic>MR</italic>3</sup>, and <italic>PvTDIFL3</italic><sup><italic>MR</italic>2</sup> were relatively high and all of them were expressed at the highest levels in the rachis of switchgrass. The precursor proteins for PvTDIFL1, PvTDIFL3<sup>MR3</sup>, and PvTDIFL3<sup>MR2</sup> contained one, three, and two TDIFL motifs, respectively. Treatments with exogenous PvTDIFL peptides increased the number of stele cells in the hypocotyls of <italic>Arabidopsis</italic> seedlings, with the exception of PvTDIFL_4p. Heterologous expression of <italic>PvTDIFL1</italic> in <italic>Arabidopsis</italic> strongly inhibited plant growth, increased cell division in the vascular tissue of the hypocotyl, and disrupted the cellular organization of the hypocotyl. Although heterologous expression of <italic>PvTDIFL3</italic><sup><italic>MR</italic>3</sup> and <italic>PvTDIFL3</italic><sup><italic>MR</italic>2</sup> also affected plant growth and vascular development, PvTDIFL activity was not enhanced by the multiple TDIFL motifs encoded by <italic>PvTDIFL3</italic><sup><italic>MR</italic>3</sup> and <italic>PvTDIFL3</italic><sup><italic>MR</italic>2</sup>. These data indicate that in general, PvTDIFLs are functionally similar to <italic>Arabidopsis</italic> TDIF but that the processing and activities of the PvTDIFL peptides are more complex.</p>