Functional characterization of an aluminum (Al)‐inducible transcription factor, ART 2, revealed a different pathway for Al tolerance in rice

Summary High aluminum (Al) tolerance in rice ( Oryza sativa ) is controlled by a Cys2His2‐type zinc finger transcription factor ART 1 (Al resistance transcription factor 1). There are five close homologs of ART 1 in the rice genome, but the role of these homologs is unknown. We functionally characterized one of the ART 1 homologs, ART 2, in terms of tissue and spatial expression, subcellular localization, transcriptional activation activity, and phenotypic analysis of the knockout lines. ART 2 was localized to the nucleus and showed a transcriptional activation potential in yeast. ART 2 was mainly expressed in the roots, but the expression level was much lower than that of ART 1 . The ART 2 expression was rapidly induced by Al in the roots of the wild‐type rice, but not in art1 mutant. Knockout of ART 2 resulted in increased sensitivity to Al toxicity, but did not alter sensitivity to different pH values. Expression profile analysis by RNA ‐sequencing showed that ART 2 was not involved in activation of genes regulated by ART 1; however, four genes seems to be regulated by ART 2, which are implicated in Al tolerance. These results indicate that ART 1 and ART 2 regulate different pathways leading to Al tolerance, and ATR 2 plays a supplementary role in Al tolerance in rice.