Plant Cell Environ:北京林業大學丨沙冬青蟲害/鹽害交互抗性機制研究(附NMT實驗體系)

NMT是基因功能的活體檢測技術，已被103位諾貝爾獎得主所在單位，及北大、清華、中科院使用。

期刊：Plant Cell & Environment

標題：Herbivore exposure alters ion fluxes and improves salt tolerance in a desert shrub

沙冬青是西北荒漠唯一的常綠闊葉灌木，是第三紀孑遺植物，國家二級瀕危物種。沙冬青生境極其惡劣，常伴隨著極端溫度、乾旱、鹽鹼、蟲害，但目前關於沙冬青生物與非生物交互抗性的研究甚少。因此，沈應柏教授研究團隊利用非損傷微測、雷射共聚焦等技術，系統研究了經昆蟲取食的沙冬青在遭受鹽脅迫時的根部離子跨膜轉運模式。該研究發現，昆蟲取食預處理可能通過激活OPR3活性誘導茉莉酸的積累，茉莉酸信號途徑的激活誘導了胞內Ca2+的迅速積累，增強了質膜H+-ATPase活性，促進了胞內過多的Na+經由Na+/H+逆向轉運體的外排，同時抑制K+的流失，有助於維持細胞內的K+/Na+平衡，最終增強沙冬青的耐鹽性。
　　
博士研究生陳迎迎為該論文第一作者，沈應柏教授為通訊作者。該研究相關工作得到國家自然科學基金項目（31270655）的資助。

Plants have evolved complex mechanisms that allow them to withstand multiple environmental stresses, including biotic and abiotic stresses.

Here, we investigated the interaction between herbivore exposure and salt stress of Ammopiptanthus nanus, a desert shrub. We found that jasmonic acid (JA) was involved in plant responses to both herbivore attack and salt stress, leading to an increased NaCl stress tolerance for herbivore-pretreated plants, and increase in K+/Na+ ratio in roots. Further evidence revealed the mechanism by which herbivore improved plant NaCl tolerance. Herbivore pretreatment reduced K+ efflux and increased Na+ efflux in plants subjected to long-term, short-term, or transient NaCl stress.

Moreover, herbivore pretreatment promoted H+ efflux by increasing plasma membrane H+-ATPase activity. This H+ efflux creates a transmembrane proton motive force that drives the Na+/H+ antiporter to expel excess Na+ into the external medium. In addition, high cytosolic Ca2+ was observed in the roots of herbivore-treated plants exposed to NaCl, and this effect may be regulated by H+-ATPase.

Taken together, herbivore exposure enhances A. nanus tolerance to salt stress by activating the JA signalling pathway, increasing plasma membrane H+-ATPase activity, promoting cytosolic Ca2+ accumulation, and then restricting K+ leakage and reducing Na+ accumulation in the cytosol.

植物已經進化出複雜的機制，可以承受多種環境脅迫，包括生物和非生物脅迫。

在這裡，我們調查了草食動物暴露與沙漠灌木沙冬青鹽脅迫之間的相互作用。我們發現茉莉酸（JA）參與了植物對食草動物侵襲和鹽脅迫的反應，導致食草動物預處理過的植物對NaCl脅迫的耐受性增加，並且根中K+ / Na+比率增加。進一步的證據揭示了草食動物改善植物NaCl耐受性的機制。草食動物預處理可降低長期，短期或短暫NaCl脅迫下植物的K+流出量並增加Na +流出量。

此外，草食動物預處理通過增加質膜H+ -ATPase活性來促進H +流出。這種H+外流產生跨膜質子原動力，該原動力驅動Na+ / H+反向轉運蛋白將過量的Na+排出到外部介質中。此外，在暴露於NaCl的食草動物處理過的植物的根部中觀察到高的胞質Ca2+，這種作用可能受H+ -ATPase調節。

總之，通過激活JA信號傳導途徑，增加質膜H+ -ATPase活性，促進胞質Ca2 +積累，然後限制K+洩漏並減少細胞質中Na +的積累，草食動物暴露增強了南芥對鹽脅迫的耐受性。

Figure 2. Effects of NaCl on the stable and transient flux of K+ along the A. nanus root axis (from 0 to 2000 μm from the root apex) with or without herbivore pretreatment. (A) The stable K+ flux was recorded along the axis of the root apex (0~2000 μm from the root tip) at 200-μm intervals, after long-term (LT) combined stresses (24-h HE + 7-d NaCl), salt stress (7-d NaCl), or no stress (control). (B) The bar chart represents the mean K+ flux value of all points along the roots following the four treatments. (C) The transient K+ flux kinetics were measured at the surface of the root, 600 μm from the tip, before and after the application of 100 mM NaCl. Three minutes of baseline data were recorded before NaCl application. The arrow indicates the time point of NaCl addition. Ten minutes of data were recorded after NaCl application. Samples were pretreated with tetraethylammonium (TEA), a K+ channel blocker, for 30 min before test. (D) The mean K+ flux was calculated before (pre-exposure), immediately after (peak-response), and 10 min after (post-exposure) the NaCl treatment. Different letters indicate significant differences at P ≤ 0.05 (Student’s t-test). Data were obtained from 5–7 A. nanus individuals. Error bars represent SE.

文章連結：

https://onlinelibrary.wiley.com/doi/10.1111/pce.13662

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關鍵詞：非損傷微測技術，Ca2+，K+，Na+，H+，離子流，鹽脅迫