Regulation of plant growth and development by extracellular nucleotides
Regulation of plant growth and development by extracellular nucleotides
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DOI：
10.1007/978-3-540-28516-8_15
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
S. Roux;C. Song;Collene R. Jeter
中科院分区：
文献类型：
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作者：
S. Roux;C. Song;Collene R. Jeter
传统上强调的ATP和其他核苷酸的作用是在能量代谢中，它们都发生在细胞的质膜边界内。然而，最近的研究发现，首先在动物中，然后在植物中，表明ATP和ADP可以在质膜外作为激动剂发挥重要作用，无需水解即可诱导细胞内的各种信号反应。本章综述了主要在拟南芥中获得的结果，这些结果指出细胞外核苷酸可能在植物生长和发育中起调节作用。在40-60µM范围内的ATP浓度通过伤口从细胞释放到植物组织的细胞间隙，较低水平的ATP（而不是AMP或磷酸盐）可以诱导细胞质钙离子浓度的增加和钙依赖的下游反应，如超氧化物产生的增加和与伤口反应相关的信使rna水平的增加，如脂氧合酶和1-氨基环丙烷-1-羧酸合成酶。钙信号的抑制剂（钙螯合剂、La3+、Gd3+、钙调素拮抗剂）和动物嘌呤受体的抑制剂可抑制ATP在植物中的诱导作用。由于植物的生长区域是高分泌活性的区域，并且由于分泌囊泡含有毫摩尔水平的ATP，当它们与质膜融合时，这些ATP被传递到植物的细胞外基质中，细胞外ATP也可能在未损伤组织的生长过程中发挥信号作用，本文对已发表的证据进行了回顾和讨论。尽管细胞外核苷酸在动物细胞中是公认的激动剂，但迄今为止，它们在植物中作用的证据只是间接的。嘌呤受体的发现和鉴定是确认细胞外核苷酸在动物中是信号剂的突破，并且需要在植物中类似的ATP-/ adp反应受体的鉴定来确认这些药物是植物代谢的细胞外调节剂。
The traditionally emphasized roles of ATP and other nucleotides are in energy metabolism, and they all happen within the borders of the plasma membrane of cells. However, recent findings, first in animals and then in plants, indicate that ATP and ADP can have significant roles outside the plasma membrane as agonists that do not have to be hydrolyzed to induce diverse signaling responses in cells. This chapter reviews results obtained mainly inArabidopsisthat point to a likely role of extracellular nucleotides as regulators of plant growth and development. Concentrations of ATP in the 40–60-µM range are released from cells into intercellular spaces of plant tissues by wounds, and lower levels of applied ATP, but not AMP or phosphate, can induce increases in the concentration of cytoplasmic calcium ions and such calcium-dependent downstream responses as increased superoxide production and increased levels of messenger RNAs associated with wound responses such as lipoxygenase and 1-aminocyclopropane-1-carboxylic acid synthase. Inhibitors of calcium signaling (calcium chelators, La3+, Gd3+, calmodulin antagonists) and inhibitors of animal purinoceptors suppress the inductive effects of ATP in plants. Because growth zones of plants are regions of high secretory activity and because secretory vesicles contain millimolar levels of ATP that are delivered to the plant extracellular matrix when they fuse with the plasma membrane, extracellular ATP could also play a signaling role during growth of unwounded tissues, and published evidence for this is reviewed and discussed here. Although extracellular nucleotides are well-established agonists in animal cells, the evidence for their role in plants is thus far only indirect. The discovery and characterization of purinoceptors was the breakthrough that confirmed extracellular nucleotides were signaling agents in animals, and a similar identification of ATP-/ADP-responsive receptors in plants will be required to confirm that these agents are extracellular regulators of plant metabolism.