Functional Characterization of Aluminum (Al)-Responsive Membrane-Bound NAC Transcription Factors in Soybean Roots

The membrane-bound NAC transcription (NTL) factors have been demonstrated to participate in the regulation of plant development and the responses to multiple environmental stresses. This study is aimed to functionally characterize soybean NTL transcription factors in response to Al-toxicity, which is largely uncharacterized. The qRT-PCR assays in the present study found that thirteen out of fifteen genes in the soybean genome were up-regulated by Al toxicity. However, among the Al-up-regulated s selected from six duplicate gene pairs, only overexpressing , , and could confer Arabidopsis Al resistance. Further comprehensive functional characterization of showed that the expression of this gene in response to Al stress depended on root tissues, as well as the Al concentration and period of Al treatment. Overexpression of conferred Al tolerance of transgenic Arabidopsis in long-term (48 and 72 h) Al treatments. Moreover, RNA-seq assay identified 517 DEGs regulated by GmNTL4 in Arabidopsis responsive to Al stress, which included s, s, s, and s. These results suggest that the function of s in Al responses is divergent, and might confer Al resistance partially by regulating the expression of genes involved in organic acid efflux and cell wall modification.