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Rapid depolarization and cytosolic calcium increase go hand-in-hand in mesophyll cells’ ozone response
New Phytologist ( IF 9.4 ) Pub Date : 2021-09-04 , DOI: 10.1111/nph.17711
Maris Nuhkat 1 , Mikael Brosché 2 , Sonja Stoelzle-Feix 3 , Petra Dietrich 4 , Rainer Hedrich 5 , M Rob G Roelfsema 5 , Hannes Kollist 1
Affiliation  

  • Plant stress signalling involves bursts of reactive oxygen species (ROS), which can be mimicked by the application of acute pulses of ozone. Such ozone-pulses inhibit photosynthesis and trigger stomatal closure in a few minutes, but the signalling that underlies these responses remains largely unknown.
  • We measured changes in Arabidopsis thaliana gas exchange after treatment with acute pulses of ozone and set up a system for simultaneous measurement of membrane potential and cytosolic calcium with the fluorescent reporter R-GECO1.
  • We show that within 1 min, prior to stomatal closure, O3 triggered a drop in whole-plant CO2 uptake. Within this early phase, O3 pulses (200–1000 ppb) elicited simultaneous membrane depolarization and cytosolic calcium increase, whereas these pulses had no long-term effect on either stomatal conductance or photosynthesis. In contrast, pulses of 5000 ppb O3 induced cell death, systemic Ca2+ signals and an irreversible drop in stomatal conductance and photosynthetic capacity.
  • We conclude that mesophyll cells respond to ozone in a few seconds by distinct pattern of plasma membrane depolarizations accompanied by an increase in the cytosolic calcium ion (Ca2+) level. These responses became systemic only at very high ozone concentrations. Thus, plants have rapid mechanism to sense and discriminate the strength of ozone signals.


中文翻译:

叶肉细胞的臭氧反应中快速去极化和细胞溶质钙增加密切相关

  • 植物应激信号涉及活性氧 (ROS) 的爆发,这可以通过应用臭氧的急性脉冲来模拟。这种臭氧脉冲会在几分钟内抑制光合作用并触发气孔关闭,但作为这些反应基础的信号仍然很大程度上未知。
  • 我们测量了用急性臭氧脉冲处理后拟南芥气体交换的变化,并建立了一个系统,用荧光报告基因 R-GECO1 同时测量膜电位和细胞溶质钙。
  • 我们表明,在气孔关闭之前的 1 分钟内,O 3引发了整个植物 CO 2吸收的下降。在这个早期阶段,O 3脉冲(200-1000 ppb)同时引起膜去极化和细胞溶质钙增加,而这些脉冲对气孔导度或光合作用都没有长期影响。相比之下,5000 ppb O 3脉冲会诱导细胞死亡、系统性 Ca 2+信号以及气孔导度和光合能力的不可逆下降。
  • 我们得出结论,叶肉细胞在几秒钟内通过不同的质膜去极化模式对臭氧做出反应,并伴随着细胞溶质钙离子 (Ca 2+ ) 水平的增加。只有在非常高的臭氧浓度下,这些反应才成为全身性的。因此,植物具有感知和区分臭氧信号强度的快速机制。
更新日期:2021-10-20
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