两种大豆二酰甘油酰基转移酶在三酰基甘油生物合成以及对环境胁迫和激素的响应中起着不同的作用。

Two types of soybean diacylglycerol acyltransferases are differentially involved in triacylglycerol biosynthesis and response to environmental stresses and hormones.

机构信息

National Key Laboratory of Crop Genetic Improvement, College of Plant Science &Technology, Huazhong Agricultural University, Wuhan, 430070, China.

College of Agronomy, Jilin Agricultural University, Changchun, 130047, China.

出版信息

Sci Rep. 2016 Jun 27;6:28541. doi: 10.1038/srep28541.

Diacylglycerol acyltransferases (DGATs) play a key role in plant triacylglycerol (TAG) biosynthesis. Two type 1 and 2 DGATs from soybean were characterized for their functions in TAG biosynthesis and physiological roles. GmDGAT1A is highly expressed in seeds while GmDGAT2D is mainly expressed in flower tissues. They showed different expression patterns in response to biotic and abiotic stresses. GmDGAT2D was up-regulated by cold and heat stress and ABA signaling, and repressed by insect biting and jasmonate, whereas GmDGAT1A show fewer responses. Both GmDGAT1A and GmDGAT2D were localized to the endoplasmic reticulum and complemented the TAG deficiency of a yeast mutant H1246. GmDGAT2D-transgenic hairy roots synthesized more 18:2- or 18:1-TAG, whereas GmDGAT1A prefers to use 18:3-acyl CoA for TAG synthesis. Overexpression of both GmDGATs in Arabidopsis seeds enhanced the TAG production; GmDGAT2D promoted 18:2-TAG in wild-type but enhanced 18:1-TAG production in rod1 mutant seeds, with a decreased 18:3-TAG. However, GmDGAT1A enhanced 18:3-TAG and reduced 20:1-TAG contents. The different substrate preferences of two DGATs may confer diverse fatty acid profiles in soybean oils. While GmDGAT1A may play a role in usual seed TAG production and GmDGAT2D is also involved in usual TAG biosynthesis in other tissues in responses to environmental and hormonal cues.

二酰甘油酰基转移酶（DGATs）在植物三酰基甘油（TAG）生物合成中发挥关键作用。从大豆中鉴定了两种 1 型和 2 型 DGATs，以研究它们在 TAG 生物合成中的功能和生理作用。GmDGAT1A 在种子中高度表达，而 GmDGAT2D 主要在花组织中表达。它们对生物和非生物胁迫的反应表现出不同的表达模式。GmDGAT2D 受到冷、热胁迫和 ABA 信号的上调，受到昆虫叮咬和茉莉酸的抑制，而 GmDGAT1A 则表现出较少的反应。GmDGAT1A 和 GmDGAT2D 均定位于内质网，并互补酵母突变体 H1246 的 TAG 缺陷。GmDGAT2D 转基因毛状根合成更多的 18:2-或 18:1-TAG，而 GmDGAT1A 则更喜欢使用 18:3-酰基辅酶 A 进行 TAG 合成。在拟南芥种子中过表达两种 GmDGATs 均可增强 TAG 产量；GmDGAT2D 在野生型中促进 18:2-TAG 的合成，但在 rod1 突变体种子中增强 18:1-TAG 的合成，同时降低 18:3-TAG 的含量。然而，GmDGAT1A 则增强了 18:3-TAG，并降低了 20:1-TAG 的含量。两种 DGATs 的不同底物偏好可能使大豆油具有不同的脂肪酸组成。虽然 GmDGAT1A 可能在通常的种子 TAG 生产中发挥作用，而 GmDGAT2D 也可能在其他组织中通常的 TAG 生物合成中发挥作用，以响应环境和激素信号。