Accumulation of trehalose in response to desiccation and salt stress in the terrestrial cyanobacterium Nostoc commune
Accumulation of trehalose in response to desiccation and salt stress in the terrestrial cyanobacterium Nostoc commune
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DOI：
10.1111/j.1440-1835.2008.00522.x
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发表时间：
2009-03-01
影响因子：
1.5
通讯作者：
Tamaru, Yoshiyuki
中科院分区：
文献类型：
--
作者：
Sakamoto, Toshio;Yoshida, Takayuki;Tamaru, Yoshiyuki
研究了田间分离的地木耳自然菌落在干旱和盐胁迫下光合活性和海藻糖水平的变化。随着N.在干燥过程中，光合放氧活性下降，而干燥的群体中没有检测到活性。高水平的O-2进化恢复的殖民地，因为他们吸收大气中的水分，表明只有少量的水是需要重新激活光合作用。在完全水合的N.公社殖民地;然而，海藻糖的积累响应于干燥过程中的水分损失而发生，并且在空气干燥的菌落中检测到高水平的海藻糖。此外，0.2 M NaCl处理也诱导海藻糖积累的水平相当于通过干燥。0.2 M NaCl抑制光合作用O-2释放，表明N.公社只能容忍低水平的盐。这些结果表明，停止光合作用和海藻糖的积累发生在响应基质水胁迫（干燥）和渗透水胁迫（高盐浓度），而海藻糖可能是一个不太有效的植物保护化合物比别人，它是非常重要的极端耐受性，在陆地蓝藻中观察到的干燥。
Changes in photosynthetic activity and trehalose levels in field-isolated, natural colonies of the terrestrial cyanobacterium Nostoc commune responding to desiccation and salt stress were investigated. As the water content decreased in N. commune colonies during desiccation, photosynthetic O-2-evolving activity decreased and no activity was detected in desiccated colonies. A high level of O-2 evolution was restored in the colonies as they absorbed atmospheric moisture, indicating that only a small amount of water is required for reactivation of photosynthesis. No detectable trehalose was found in fully hydrated N. commune colonies; however, trehalose accumulation occurred in response to water loss during desiccation and high levels of trehalose were detected in the air-dried colonies. Moreover, a 0.2 M NaCl treatment also induced trehalose accumulation to a level equivalent to that by desiccation. Photosynthetic O-2 evolution was inhibited by 0.2 M NaCl, indicating that N. commune can tolerate only low levels of salt. These results suggest that cessation of photosynthesis and trehalose accumulation occur in response to both matric water stress (desiccation) and osmotic water stress (high salt concentration), and that while trehalose may be a less effective osmoprotective compound than others, it is important for the extreme tolerance to desiccation observed in terrestrial cyanobacterium.