Kanno Satomi, Martin Ludovic, Vallier Natacha, Chiarenza Serge, Nobori Tatsuya, Furukawa Jun, Nussaume Laurent, Vavasseur Alain, Leonhardt Nathalie
AixMarseille University, French Alternative Energies and Atomic Energy Commission (CEA), National Center for Scientific Research (CNRS), Bioscience and Biotechnology Institute of Aix-Marseille (BIAM), Saint-Paul Lez Durance, France.
Faculty of Life and Environmental Sciences University of Tsukuba, Tsukuba, Ibaraki, Japan.
Front Plant Sci. 2023 Sep 22;14:1040118. doi: 10.3389/fpls.2023.1040118. eCollection 2023.
Potassium (K) is an essential macronutrient for plant growth. The transcriptional regulation of K transporter genes is one of the key mechanisms by which plants respond to K deficiency. Among the transporter family, HAK5, a high-affinity K transporter, is essential for root K uptake under low external K conditions. expression in the root is highly induced by low external K concentration. While the molecular mechanisms of regulation have been extensively studied, it remains unclear how plants sense and coordinates K uptake and translocation in response to changing environmental conditions. Using mutants, which have a defect in root-to-shoot K translocation, we have been able to determine how the internal K status affects the expression of . In mutant roots, under K deficiency, expression was lower than in wild-type although the K concentration in roots was not significantly different. These results reveal that is not only regulated by external K conditions but it is also regulated by internal K levels, which is in agreement with recent findings. Additionally, HAK5 plays a major role in the uptake of Cs in roots. Therefore, studying Cs in roots and having more detailed information about its uptake and translocation in the plant would be valuable. Radioactive tracing experiments revealed not only a reduction in the uptake of Cs and Kin mutants compared to wild-type but also a different distribution of Cs and K in tissues. In order to gain insight into the translocation, accumulation, and repartitioning of both K and Cs in plants, long-term treatment and split root experiments were conducted with the stable isotopes Cs and Rb. Finally, our findings show that the K distribution in plant tissues regulates root uptake of K and Cs similarly, depending on ; however, the translocation and accumulation of the two elements are different.
钾（K）是植物生长必需的大量营养素。钾转运蛋白基因的转录调控是植物应对钾缺乏的关键机制之一。在转运蛋白家族中，高亲和性钾转运蛋白HAK5在低外部钾条件下对根系吸收钾至关重要。其在根中的表达受低外部钾浓度高度诱导。虽然对其调控的分子机制已进行了广泛研究，但尚不清楚植物如何感知并协调钾的吸收和转运以响应不断变化的环境条件。利用在根到地上部钾转运方面存在缺陷的突变体，我们得以确定内部钾状态如何影响HAK5的表达。在突变体根中，在钾缺乏条件下，尽管根中的钾浓度无显著差异，但HAK5的表达低于野生型。这些结果表明，HAK5不仅受外部钾条件调控，还受内部钾水平调控，这与最近的研究结果一致。此外，HAK5在根系吸收铯（Cs）中起主要作用。因此，研究根系中的铯及其在植物体内的吸收和转运的更详细信息将很有价值。放射性示踪实验表明，与野生型相比，突变体中铯和钾的吸收不仅减少，而且铯和钾在组织中的分布也不同。为了深入了解钾和铯在植物中的转运、积累和重新分配，用稳定同位素铯和铷进行了长期处理和分根实验。最后，我们的研究结果表明，植物组织中的钾分布对钾和铯根系吸收的调控类似，取决于；然而，这两种元素的转运和积累是不同的。
