The hpa1 mutant of Arabidopsis reveals a crucial role of histidine homeostasis in root meristem maintenance
The hpa1 mutant of Arabidopsis reveals a crucial role of histidine homeostasis in root meristem maintenance
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DOI：
10.1104/pp.106.084178
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发表时间：
2006-08-01
期刊：
影响因子：
7.4
通讯作者：
Wu, Ping
中科院分区：
文献类型：
--
作者：
Mo, Xiaorong;Zhu, Qingyu;Wu, Ping
组氨酸（His）是蛋白质合成的重要成分，是所有生物体所必需的。在高等植物中，虽然有相当多的证据表明组氨酸对植物的生长和生存是必不可少的，但关于它是否在植物发育中发挥任何特定作用的信息很少。在这里，我们提出的证据，这种作用的氨基酸在拟南芥（拟南芥）的根发育的一种新的拟南芥突变体，hpa1，它有一个非常短的根系统，并携带突变的两个拟南芥组氨醇磷酸氨基转移酶（HPA）基因之一，AtHPA 1的表征。我们已经确定，AtHPA 1编码一个功能性HPA，它的完全敲除是胚胎致死。生化分析表明，hpa 1的突变仅导致游离His含量减少30%，对总His含量没有显着影响。它没有引起任何已知的饥饿症状。然而，突变体表现出一个特定的发育缺陷，在根分生组织的维护和无法维持初生根生长萌发后2天。我们已经证明，突变体中的根分生组织失败与游离His含量的减少紧密相关，并且可以通过外源His补充或AtHPA 1过表达来拯救。因此，我们的研究结果揭示了他的稳态在植物发育中的重要作用。
Histidine ( His) is an essential ingredient for protein synthesis and is required by all living organisms. In higher plants, although there is considerable evidence that His is essential for plant growth and survival, there is very little information as to whether it plays any specific role in plant development. Here, we present evidence for such a role of this amino acid in root development in Arabidopsis ( Arabidopsis thaliana) from the characterization of a novel Arabidopsis mutant, hpa1, which has a very short root system and carries a mutation in one of the two Arabidopsis histidinol-phosphate aminotransferase (HPA) genes, AtHPA1. We have established that AtHPA1 encodes a functional HPA and that its complete knockout is embryo lethal. Biochemical analysis shows that the mutation in hpa1 only resulted in a 30% reduction in free His content and had no significant impact on the total His content. It did not cause any known symptoms of His starvation. However, the mutant displayed a specific developmental defect in root meristem maintenance and was unable to sustain primary root growth 2 d after germination. We have demonstrated that the root meristem failure in the mutant is tightly linked to the reduction in free His content and could be rescued by either exogenous His supplementation or AtHPA1 overexpression. Our results therefore reveal an important role of His homeostasis in plant development.