Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, Guangdong, China.
Robert Holley Center, US Department of Agriculture, Agricultural Research Service, Cornell University, Ithaca, NY, 14853, USA.
BMC Plant Biol. 2020 Mar 18;20(1):122. doi: 10.1186/s12870-020-02338-y.
In Arabidopsis, the aluminum (Al) exclusion mechanism is mainly facilitated by ALMT1-mediated malate exudation and MATE-mediated citrate releases from the root. Recently, we have demonstrated that coordinated functioning between an ALMT1-mediated Al exclusion mechanism, via exudation of malate from the root tip, and a NIP1;2-facilitated internal detoxification mechanism, via removal of Al from the root cell wall and subsequent root-to-shoot Al translocation, plays critical roles in achieving overall Al resistance. However, the genetic relationship between ALMT1 and NIP1;2 in these processes remained unclear.
Through genetic and physiological analyses, we demonstrate that unlike ALMT1 and MATE, which function independently and additively, ALMT1 and NIP1;2 show an epistatic relationship in Al resistance. These results indicate that ALMT1 and NIP1;2 function in the same biochemical pathway, whereas ALMT1 and MATE in different ones.
The establishment of the epistatic relationship and the coordinated functioning between the ALMT1 and NIP1;2-mediated exclusion and internal detoxification mechanisms are pivotal for achieving overall Al resistance in the non-accumulating Arabidopsis plant. We discuss and emphasize the indispensable roles of the root cell wall for the implementation of the Al exclusion mechanism and for the establishment of an epistatic relationship between the ALMT1-mediated exclusion mechanism and the NIP1;2-facilitated internal detoxification mechanism.
在拟南芥中，铝（Al）排斥机制主要通过 ALMT1 介导的苹果酸外排和 MATE 介导的柠檬酸从根部释放来实现。最近，我们已经证明，通过根尖的苹果酸外排，ALMT1 介导的 Al 排斥机制与 NIP1;2 促进的内部解毒机制之间的协调作用，通过从根细胞壁中去除 Al 以及随后的根到茎 Al 转运，在实现整体 Al 抗性方面起着关键作用。然而，在这些过程中，ALMT1 和 NIP1;2 之间的遗传关系仍不清楚。
通过遗传和生理分析，我们证明，与独立且累加作用的 ALMT1 和 MATE 不同，ALMT1 和 NIP1;2 在 Al 抗性中表现出上位性关系。这些结果表明，ALMT1 和 NIP1;2 作用于同一生化途径，而 ALMT1 和 MATE 则作用于不同的途径。
ALMT1 和 NIP1;2 介导的排斥和内部解毒机制之间建立上位性关系和协调作用，对于实现非积累型拟南芥植物的整体 Al 抗性至关重要。我们讨论并强调了根细胞壁在实施 Al 排斥机制以及在 ALMT1 介导的排斥机制和 NIP1;2 促进的内部解毒机制之间建立上位性关系方面的不可或缺作用。
