Lipoxygenase 2 functions in exogenous nitric oxide-induced stomatal closure in Arabidopsis thaliana
Lipoxygenase 2 functions in exogenous nitric oxide-induced stomatal closure in Arabidopsis thaliana
复制标题
脂氧合酶 2 在外源一氧化氮诱导拟南芥气孔关闭中发挥作用
DOI：
10.1071/fp15151
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发表时间：
2015
影响因子：
3
通讯作者：
Lin Hong Hui
中科院分区：
文献类型：
--
作者：
Sun Yanfeng;Lv Dong;Wang Wei;Xu Wei;Wang Li;Miao Chen;Lin Hong Hui
一氧化氮(NO)和脂氧合酶(LOX)产生的氧化脂质在植物气孔关闭中起重要作用，叶肉细胞中存在LOX-NO串扰。然而，这种串扰是否也存在于保卫细胞中尚不清楚，其具体机制也尚不清楚。在这里，我们报道了外源硝普钠(SNP，一种NO供体)诱导的气孔关闭在AtLOX2缺失突变体LOX2-1中明显受损，与野生型(WT)拟南芥(Arabiopsis thaliana(L.)海因。膜片钳分析表明，SNP抑制的LOX2-1保卫细胞原生质体内向整流钾通道活性降低。此外，SNP促进LOX2-1突变体保卫细胞内钙离子浓度的升高，但与野生型相比受到抑制。这些结果表明，AtLOX2通过影响保卫细胞内钙离子浓度的升高和内向整流钾通道的活性，在NO诱导的气孔关闭过程中发挥重要作用。此外，在正常生长条件下，LOX2-1突变体表现出较高的失水率和较宽的气孔开度。这些数据表明，AtLOX2可能通过增加拟南芥中氧磷脂的生成来调节气孔运动。
Nitric oxide (NO) and lipoxygenase (LOX)-derived oxylipins play important roles in stomatal closure in plants, and LOX–NO crosstalk has been indicated in mesophyll cells. However, whether the crosstalk also exists in guard cells is not clear and the detailed mechanisms remain unknown. Here, we report that exogenous sodium nitroprusside (SNP, a NO donor)-induced stomatal closure was clearly impaired in the AtLOX2 null mutant lox2–1 compared with wild-type (WT) Arabidopsis thaliana (L.) Heynh. Patch clamp analysis showed that the SNP-suppressed activity of inward-rectifying potassium channels in lox2–1 guard cell protoplasts was reduced. Moreover, SNP promoted an increase in cytosolic Ca2+ concentration in guard cells of lox2–1 mutants was inhibited compared with the WT. These results suggest that AtLOX2 plays an important role in NO-induced stomatal closure by affecting the cytosolic Ca2+ concentration increase and the activity of inward-rectifying potassium channels in guard cells. Furthermore, lox2–1 mutants showed a higher rate of leaf water loss and a relatively wider stomatal aperture than the WT under normal growth conditions. These data imply that AtLOX2 might modulate stomatal movement by increasing oxylipin generation in A. thaliana.