Abstract
AbstractAluminum (Al) toxicity and low pH are major factors limiting plant growth in acidic soils. Sensitive to Proton Rhizotoxicity 1 (STOP1) transcription factor respond to these stresses by regulating the expression of multiple Al- or low pH-responsive genes. ZmSTOP1-A, a STOP1-like protein from maize (Zea mays), was localized to the nucleus and had transactivation activity.ZmSTOP1-Awas expressed moderately in both roots and shoots of maize seedlings, but was not induced by Al stress or low pH. Overexpression ofZmSTOP1-Ain ArabidopsisAtstop1mutant partially restored Al tolerance and completely low pH tolerance with respect to root growth. Regarding Al tolerance,ZmSTOP1-A/Atstop1plants showed clear upregulation of organic acid transporter genes, and leading to increased organic acid secretion and reduced Al accumulation in roots. Besides, the antioxidant enzyme activity in roots and shoots ofZmSTOP1-A/Atstop1plants was significantly enhanced, ultimately alleviating Al toxicity via scavenging reactive oxygen species. Similarly, ZmSTOP1-A could directly activateZmMATE1expression in maize, positively correlated with the number of Al-responsive GGNVScis-element in theZmMATE1promoter. Our results revealed that ZmSTOP1-A antagonizes Al toxicity by enhancing organic acid secretion and reactive oxygen species scavenging in Arabidopsis, demonstrating that it is an important transcription factor conferring Al tolerance. Our findings help to comprehensively elucidate the role of STOP1-like transcript factor in enabling plants to detoxifying Al.
Publisher
Cold Spring Harbor Laboratory