Identification of acyltransferases required for cutin biosynthesis and production of cutin with suberin-like monomers
Identification of acyltransferases required for cutin biosynthesis and production of cutin with suberin-like monomers
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DOI：
10.1073/pnas.0706984104
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发表时间：
2007-11-13
影响因子：
11.1
通讯作者：
Ohlrogge, John
中科院分区：
文献类型：
--
作者：
Li, Yonghua;Beisson, Fred;Ohlrogge, John
木栓素和木栓素是植物中两种主要的脂质聚合物。角质层是表皮角质层的结构聚合物，覆盖初级气生器官的防水层，并且其通常是植物病原体首先遇到的结构。Suberin有助于控制水和溶质穿过内部根组织和周皮的扩散。负责角质聚合物组装的酶在很大程度上是未知的。我们已经确定了两个拟南芥酰基转移酶角质生物合成所必需的，甘油-3-磷酸酰基转移酶（GPAT）4和GPAT 8。双基因敲除gpat 4/gpat 8强烈减少角质和抗干燥和真菌Alternaria brassicicicola的感染。它们还表现出气孔结构的显著缺陷，包括保卫细胞之间缺乏角质壁架，突出了角质在气孔生物学中的重要性。在拟南芥中过表达GPAT 4或GPAT 8使C16和C18角质单体的含量增加了80%。为了改变角质组成，酰基转移酶GPAT 5和细胞色素P450依赖性脂肪酰基氧化酶CYP 86 A1，与木栓质生物合成相关的两种酶，过表达。当这两种酶一起过度表达的表皮聚酯积累新的C20和C22 ω-羟基酸和α ω-二酸典型的木栓质，和精细结构和水屏障功能的角质层被改变。这些结果确定GPAT的脂肪酰氧化酶在脂质聚酯合成的合作伙伴，并表明，他们的cooverexpression提供了一种策略，以探测角质成分和数量的作用，在植物角质的功能。
Cutin and suberin are the two major lipid-based polymers of plants. Cutin is the structural polymer of the epidermal cuticle, the waterproof layer covering primary aerial organs and which is often the structure first encountered by phytopathogens. Suberin contributes to the control of diffusion of water and solutes across internal root tissues and in periderms. The enzymes responsible for assembly of the cutin polymer are largely unknown. We have identified two Arabidopsis acyltransferases essential for cutin biosynthesis, glycerol-3-phosphate acyltransferase (GPAT) 4 and GPAT8. Double knockouts gpat4/gpat8 were strongly reduced in cutin and were less resistant to desiccation and to infection by the fungusAlternaria brassicicola. They also showed striking defects in stomata structure including a lack of cuticular ledges between guard cells, highlighting the importance of cutin in stomatal biology. Overexpression of GPAT4 or GPAT8 in Arabidopsis increased the content of C16 and C18 cutin monomers in leaves and stems by 80%. In order to modify cutin composition, the acyltransferase GPAT5 and the cytochrome P450-dependent fatty acyl oxidase CYP86A1, two enzymes associated with suberin biosynthesis, were overexpressed. When both enzymes were overexpressed together the epidermal polyesters accumulated new C20 and C22 omega-hydroxyacids and alpha omega-diacids typical of suberin, and the fine structure and water-barrier function of the cuticle were altered. These results identify GPATs as partners of fatty acyl oxidases in lipid polyester synthesis and indicate that their cooverexpression provides a strategy to probe the role of cutin composition and quantity in the function of plant cuticles.