AUTHOR=Yang Xuefei , Kim Moon Young , Ha Jungmin , Lee Suk-Ha 

TITLE=Overexpression of the Soybean NAC Gene GmNAC109 Increases Lateral Root Formation and Abiotic Stress Tolerance in Transgenic Arabidopsis Plants

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01036

DOI=10.3389/fpls.2019.01036

ISSN=1664-462X

ABSTRACT=<p>NACs are plant-specific transcription factors that have crucial roles in plant development and biotic and/or abiotic stress responses. This study characterized the functions of the soybean NAC gene <italic>GmNAC109</italic> using an overexpression construct in <italic>Arabidopsis</italic> lines. Sequence analysis revealed that <italic>GmNAC109</italic> is highly homologous to <italic>ATAF1</italic> (<italic>Arabidopsis Transcription Activation Factor 1</italic>), which regulates biotic and abiotic stress responses. GmNAC109 protein localized to the nucleus and its C-terminal domain exhibited transcriptional activation activity. Salt, dehydration, and cold stresses significantly increased expression of <italic>GmNAC109</italic> in soybean. Similarly, <italic>Arabidopsis</italic> plants overexpressing <italic>GmNAC109</italic> were more tolerant to drought and salt stress than wild-type Col-0 plants. Stress response-related genes, such as <italic>DREB1A</italic> (<italic>drought-responsive element-binding 1A</italic>), <italic>DREB2A</italic>, <italic>AREB1</italic> (<italic>ABSCISIC ACID-RESPONSIVE ELEMENT BINDING PROTEIN 1</italic>), <italic>AREB2</italic>, <italic>RD29A</italic> (<italic>RESPONSIVE TO Desiccation 29A</italic>), and <italic>COR15A</italic> (<italic>COLD REGULATED 15A</italic>) were upregulated in <italic>GmNAC109</italic>-overexpressing transgenic <italic>Arabidopsis</italic> lines. The transgenic lines showed upregulation of the ABA-responsive genes <italic>ABI1</italic> (<italic>ABA INSENSITIVE 1</italic>) and <italic>ABI5</italic> and hypersensitivity to ABA. However, <italic>GmNAC109</italic> did not increase expression of the ABA-biosynthetic gene <italic>NCED3</italic> (<italic>NINE-CIS-EPOXYCAROTENOID DIOXYGENASE</italic> 3) and endogenous ABA content in the transgenic lines. Overexpression of <italic>GmNAC109</italic> significantly increased lateral root formation in transgenic <italic>Arabidopsis</italic> lines. Expression of <italic>AIR3</italic> (<italic>AUXIN-INDUCED IN ROOT CULTURES 3</italic>) and <italic>ARF2</italic> (<italic>AUXIN RESPONSE FACTOR 2</italic>) was increased and decreased in these transgenic lines, respectively, indicating that <italic>GmNAC109</italic> is involved in the auxin signaling pathway and thereby helps to regulate hairy root formation. Our results provide a basis for development of soybean lines with improved tolerance to abiotic stresses <italic>via</italic> genetic manipulation.</p>