Wu Jian-Xin, Li Jian, Liu Zhe, Yin Jian, Chang Zhen-Yi, Rong Chan, Wu Jia-Li, Bi Fang-Cheng, Yao Nan
State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resource, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
Plant J. 2015 Mar;81(5):767-80. doi: 10.1111/tpj.12769.
Ceramidases hydrolyze ceramide into sphingosine and fatty acids. In mammals, ceramidases function as key regulators of sphingolipid homeostasis, but little is known about their roles in plants. Here we characterize the Arabidopsis ceramidase AtACER, a homolog of human alkaline ceramidases. The acer-1 T-DNA insertion mutant has pleiotropic phenotypes, including reduction of leaf size, dwarfing and an irregular wax layer, compared with wild-type plants. Quantitative sphingolipid profiling showed that acer-1 mutants and the artificial microRNA-mediated silenced line amiR-ACER-1 have high ceramide levels and decreased long chain bases. AtACER localizes predominantly to the endoplasmic reticulum, and partially to the Golgi complex. Furthermore, we found that acer-1 mutants and AtACER RNAi lines showed increased sensitivity to salt stress, and lines overexpressing AtACER showed increased tolerance to salt stress. Reduction of AtACER also increased plant susceptibility to Pseudomonas syringae. Our data highlight the key biological functions of ceramidases in biotic and abiotic stresses in plants.
神经酰胺酶将神经酰胺水解为鞘氨醇和脂肪酸。在哺乳动物中，神经酰胺酶是鞘脂稳态的关键调节因子，但它们在植物中的作用却鲜为人知。在此，我们对拟南芥神经酰胺酶AtACER进行了表征，它是人类碱性神经酰胺酶的同源物。与野生型植物相比，acer-1 T-DNA插入突变体具有多效性表型，包括叶片尺寸减小、植株矮化和蜡质层不规则。鞘脂定量分析表明，acer-1突变体和人工miRNA介导的沉默株系amiR-ACER-1具有较高的神经酰胺水平和减少的长链碱基。AtACER主要定位于内质网，部分定位于高尔基体复合体。此外，我们发现acer-1突变体和AtACER RNA干扰株系对盐胁迫的敏感性增加，而过表达AtACER的株系对盐胁迫的耐受性增加。AtACER的减少也增加了植物对丁香假单胞菌的易感性。我们的数据突出了神经酰胺酶在植物生物和非生物胁迫中的关键生物学功能。
