PDF(Pubmed)
Abstract：
Leaf wounding triggers rapid long-range electrical signaling that initiates systemic defense responses to protect the plants from further attack. In Arabidopsis, this process largely depends on clade three GLUTAMATE RECEPTOR-LIKE (GLR) genes GLR3.3 and GLR3.6. In the cellular context, phloem sieve elements and xylem contact cells where GLRs were mostly present are implicated in the signaling events. In spite of that, the spatial requirements of different leaf cell types for leaf-to-leaf signaling remain poorly investigated. In this study, we dissected cell-type-specific long-distance wound signaling mediated by GLR3s and showed that phloem companion cells are critical in shaping the functions of GLR3.3 and GLR3.6 in the signaling pathway. GLR3.3-mediated response is phloem-specific, during which, GLR3.3 has to be renewed from companion cells to allow its function in sieve elements. GLR3.6 functions dually in ectopic phloem companion cells, in addition to xylem contact cells. Furthermore, the action of GLR3.6 in phloem is independent of its paralog GLR3.3 and probably requires synthesis of GLR3.6 from xylem contact cells. Overall, our work highlights that the phloem companion cell is crucial for both GLRs in controlling leaf-to-leaf electrical signaling.
摘要：
叶片受伤会触发快速的远程电信号，从而引发系统的防御反应，以保护植物免受进一步的攻击。在拟南芥中,这个过程很大程度上取决于进化枝三个谷氨酸受体（GLR）基因GLR3.3和GLR3.6。在细胞环境中，主要存在GLR的韧皮部筛元素和木质部接触细胞与信号事件有关。尽管如此,不同叶细胞类型对叶到叶信号的空间要求仍未得到充分研究。在这项研究中,我们解剖了由GLR3介导的细胞类型特异性长距离伤口信号传导,并显示韧皮部伴随细胞在信号传导途径中塑造GLR3.3和GLR3.6的功能方面至关重要.GLR3.3介导的反应是韧皮部特异性的，在此期间，GLR3.3必须从伴侣细胞更新以允许其在筛子元件中的功能。GLR3.6在异位韧皮部伴侣细胞中双重功能，除了木质部接触细胞。此外，GLR3.6在韧皮部中的作用独立于其旁系GLR3.3，可能需要从木质部接触细胞合成GLR3.6。总的来说,我们的工作强调，韧皮部伴生细胞对于控制叶到叶电信号信号的两个GLR都至关重要。
