Control of Ascorbate Peroxidase 2 expression by hydrogen peroxide and leaf water status during excess light stress reveals a functional organisation of Arabidopsis leaves
Control of Ascorbate Peroxidase 2 expression by hydrogen peroxide and leaf water status during excess light stress reveals a functional organisation of Arabidopsis leaves
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DOI：
10.1046/j.1365-313x.2003.01656.x
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发表时间：
2003-02-01
期刊：
影响因子：
7.2
通讯作者：
Baker, NR
中科院分区：
文献类型：
--
作者：
Fryer, MJ;Ball, L;Baker, NR
在拟南芥叶片中，强光胁迫诱导编码胞质抗坏血酸过氧化物酶（APX 2）的基因的快速表达，其表达仅限于维管束鞘细胞的维管组织。叶绿素荧光成像和活性氧（ROS）的产生表明，APX 2的表达后，局部增加过氧化氢（H-2 O-2）导致光合电子传递在束鞘细胞。此外，叶片蒸腾速率也增加之前APX 2的表达，这表明水分状况也可能参与信号通路。脱落酸刺激APX 2表达。ABA-不敏感的突变体（abi 1 -1，abi 2 -1）暴露于过量的光导致APX 2的表达水平降低，并证实了阿坝在信号通路中的作用。阿坝似乎增强了H-2 O-2在启动APX 2表达中的作用。APX 2的这种调节可能反映了叶片的功能组织，以解决两个相互冲突的生理要求，即保护初级光合作用位点免受ROS的影响，同时刺激ROS积累以响应光环境的变化。
In Arabidopsis leaves, high light stress induces rapid expression of a gene encoding a cytosolic ascorbate peroxidase (APX2 ), whose expression is restricted to bundle sheath cells of the vascular tissue. Imaging of chlorophyll fluorescence and the production of reactive oxygen species (ROS) indicated that APX2 expression followed a localised increase in hydrogen peroxide (H-2 O-2 ) resulting from photosynthetic electron transport in the bundle sheath cells. Furthermore, leaf transpiration rate also increased prior to APX2 expression, suggesting that water status may also be involved in the signalling pathway. Abscisic acid stimulated APX2 expression. Exposure of ABA-insensitive mutants (abi1-1 , abi2-1 ) to excess light resulted in reduced levels of APX2 expression and confirmed a role for ABA in the signalling pathway. ABA appears to augment the role of H-2 O-2 in initiating APX2 expression. This regulation of APX2 may reflect a functional organisation of the leaf to resolve two conflicting physiological requirements of protecting the sites of primary photosynthesis from ROS and, at the same time, stimulating ROS accumulation to signal responses to changes in the light environment.