AUTHOR=Wang Hongfeng , Wang Hongwei , Liu Rong , Xu Yiteng , Lu Zhichao , Zhou Chuanen 

TITLE=Genome-Wide Identification of TCP Family Transcription Factors in Medicago truncatula Reveals Significant Roles of miR319-Targeted TCPs in Nodule Development

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00774

DOI=10.3389/fpls.2018.00774

ISSN=1664-462X

ABSTRACT=<p>TCP proteins, the plant-specific transcription factors, are involved in the regulation of multiple aspects of plant development among different species, such as leaf development, branching, and flower symmetry. However, thus far, the roles of TCPs in legume, especially in nodulation are still not clear. In this study, a genome-wide analysis of <italic>TCP</italic> genes was carried out to discover their evolution and function in <italic>Medicago truncatula</italic>. In total, 21 <italic>MtTCPs</italic> were identified and classified into class I and class II, and the class II <italic>MtTCPs</italic> were further divided into two subclasses, CIN and CYC/TB1. The expression profiles of <italic>MtTCPs</italic> are dramatically different. The universal expression of class I <italic>MtTCPs</italic> was detected in all organs. However, the <italic>MtTCPs</italic> in CIN subclass were highly expressed in leaf and most of the members in CYC/TB1 subclass were highly expressed in flower. Such organ-specific expression patterns of <italic>MtTCPs</italic> suggest their different roles in plant development. In addition, most <italic>MtTCPs</italic> were down-regulated during the nodule development, except for the putative <italic>MtmiR319</italic> targets, <italic>MtTCP3, MtTCP4</italic>, and <italic>MtTCP10A</italic>. Overexpression of <italic>MtmiR319A</italic> significantly reduced the expression level of <italic>MtTCP3/4/10A/10B</italic> and resulted in the decreased nodule number, indicating the important roles of <italic>MtmiR319</italic>-targeted <italic>MtTCPs</italic> in nodulation. Taken together, this study systematically analyzes the <italic>MtTCP</italic> gene family at a genome-wide level and their possible functions in nodulation, which lay the basis for further explorations of <italic>MtmiR319/MtTCPs</italic> module in association with nodule development in <italic>M. truncatula</italic>.</p>