The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao 266237, China.
The Key Laboratory of Plant Stress Biology, School of Life Science, Henan University, JinMing Avenue, Henan University, Kaifeng 475004, China.
Int J Mol Sci. 2020 Jun 7;21(11):4080. doi: 10.3390/ijms21114080.
Aluminum (Al) stress is a major limiting factor for plant growth and crop production in acid soils. At present, only a few transcription factors involved in the regulation of Al resistance have been characterized. Here, we used reversed genetic approach through phenotype analysis of overexpressors and mutants to demonstrate that AtHB7 and AtHB12, two HD-Zip I transcription factors, participate in Al resistance. In response to Al stress, and displayed different dynamic expression patterns. Although both AtHB7 and AtHB12 positively regulate root growth in the absence of Al stress, our results showed that AtHB7 antagonizes with AtHB12 to control root growth in response to Al stress. The double mutant displayed a wild-type phenotype under Al stress. Consistently, our physiological analysis showed that AtHB7 and AtHB12 oppositely regulate the capacity of cell wall to bind Al. Yeast two hybrid assays showed that AtHB7 and AtHB12 could form homo-dimers and hetero-dimers in vitro, suggesting the interaction between AtHB7 and AtHB12 in the regulation of root growth. The conclusion was that AtHB7 and AtHB12 oppositely regulate Al resistance by affecting Al accumulation in root cell wall.
铝（Al）胁迫是酸性土壤中植物生长和作物生产的主要限制因素。目前，仅鉴定出少数参与调控耐铝性的转录因子。在这里，我们通过过表达载体和突变体的表型分析，采用反向遗传学方法证明了两个 HD-Zip I 转录因子 AtHB7 和 AtHB12 参与了耐铝性。在响应铝胁迫时，和显示出不同的动态表达模式。虽然 AtHB7 和 AtHB12 在无铝胁迫下均能正向调控根系生长，但我们的结果表明，AtHB7 拮抗 AtHB12 以调控对铝胁迫的根系生长。双突变体在铝胁迫下表现出野生型表型。同样，我们的生理分析表明，AtHB7 和 AtHB12 反向调控细胞壁结合铝的能力。酵母双杂交实验表明，AtHB7 和 AtHB12 可以在体外形成同源二聚体和异源二聚体，表明 AtHB7 和 AtHB12 之间在调控根系生长过程中存在相互作用。结论是 AtHB7 和 AtHB12 通过影响根细胞壁中铝的积累来反向调节铝抗性。
