AUTHOR=Cai Zhandong , Xian Peiqi , Wang Huan , Lin Rongbin , Lian Tengxiang , Cheng Yanbo , Ma Qibin , Nian Hai 

TITLE=Transcription Factor GmWRKY142 Confers Cadmium Resistance by Up-Regulating the Cadmium Tolerance 1-Like Genes

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00724

DOI=10.3389/fpls.2020.00724

ISSN=1664-462X

ABSTRACT=<p>Cadmium (Cd) is a widespread pollutant that is toxic to living organisms. Previous studies have identified certain WRKY transcription factors, which confer Cd tolerance in different plant species. In the present study, we have identified 29 Cd-responsive <italic>WRKY</italic> genes in Soybean [<italic>Glycine max</italic> (L.) Merr.], and confirmed that 26 of those <italic>GmWRKY</italic> genes were up-regulated, while 3 were down-regulated. We have also cloned the novel, positively regulated <italic>GmWRKY142</italic> gene from soybean and investigated its regulatory mechanism in Cd tolerance. GmWRKY142 was highly expressed in the root, drastically up-regulated by Cd, localized in the nucleus, and displayed transcriptional activity. The overexpression of <italic>GmWRKY142</italic> in <italic>Arabidopsis thaliana</italic> and soybean hairy roots significantly enhanced Cd tolerance and lead to extensive transcriptional reprogramming of stress-responsive genes. <italic>ATCDT1</italic>, <italic>GmCDT1-1</italic>, and <italic>GmCDT1-2</italic> encoding cadmium tolerance 1 were induced in overexpression lines. Further analysis showed that <italic>GmWRKY142</italic> activated the transcription of <italic>ATCDT1</italic>, <italic>GmCDT1-1</italic>, and <italic>GmCDT1-2</italic> by directly binding to the W-box element in their promoters. In addition, the functions of <italic>GmCDT1-1</italic> and <italic>GmCDT1-2</italic>, responsible for decreasing Cd uptake, were validated by heterologous expression in <italic>A. thaliana</italic>. Our combined results have determined GmWRKYs to be newly discovered participants in response to Cd stress, and have confirmed that <italic>GmWRKY142</italic> directly targets <italic>ATCDT1</italic>, <italic>GmCDT1-1</italic>, and <italic>GmCDT1-2</italic> to decrease Cd uptake and positively regulate Cd tolerance. The GmWRKY142-GmCDT1-1/2 cascade module provides a potential strategy to lower Cd accumulation in soybean.</p>