Quantitative trait loci analysis identifies a prominent gene involved in the production of fatty-acid-derived flavor volatiles in tomato

First author: Karolina Garbowicz; Affiliations: Max Planck Institute of Molecular Plant Physiology (普朗克分子植物生理研究所): Potsdam-Golm, Germany

Corresponding author: Yariv Brotman

To gain insight into the genetic regulation of lipid metabolism in tomato, we conducted metabolic trait loci (mQTL) analysis following the lipidomic profiling (脂质谱) of fruit pericarp (果皮) and leaf tissue of the Solanum pennellii introgression lines (导入系). To enhance mapping resolution for selected fruit-specific mQTL, we profiled the lipids in a subset of independently derived S. pennellii backcross inbred lines (回交重组自交系), as well as in a near-isogenic (sub-IL) population (近等基因系). We identified a putative lecithin:cholesterol acyltransferase (卵磷脂胆固醇脂酰转移酶) that controls the levels of several lipids, and two members of the class III lipase family (脂酶), LIP1 and LIP2, that were associated with decreased levels of diacylglycerols (DAGs; 甘油二酯) and triacylglycerols (TAGs; 甘油三酯). Lipases of this class cleave fatty acids (脂肪酸) from the glycerol backbone of acylglycerols (酰基甘油). The released fatty acids serve as precursors of flavor volatiles (风味挥发物). We show that LIP1 expression correlates with fatty-acid-derived volatile levels. We further confirm the function of LIP1 in TAG and DAG breakdown and volatile synthesis using transgenic plants. In summary, this study provides an extensive characterization of the genetic architecture of lipophilic compounds (亲脂化合物) in tomato in addition to zooming down to the molecular level to demonstrate that release of free fatty acids from the glycerol backbone can have a major impact on downstream volatile synthesis.

作者通过对野生种番茄导入系群体的果实果皮和叶片组织的脂质谱及代谢性状位点（mQTL）分析，研究了番茄中脂质代谢的遗传调控。为了增强受选择的果实特异性mQTL的图谱分辨率，作者在独立构建的野生种番茄回交重组自交系和近等基因系中进行了脂质谱分析。作者鉴定到了一个卵磷脂胆固醇脂酰转移酶控制一些脂质的水平，另外脂酶家族的两个基因LIP1和LIP2与甘油二酯DAG和甘油三酯TAG的衰减水平相关。该家族的脂酶能够将脂肪酸从酰基甘油的甘油骨架剪切下来。这些被释放的脂肪酸作为风味挥发物的前体。研究显示LIP1的表达与源自脂肪酸的挥发物水平相关。作者进一步通过转基因验证了LIP1在TAG和DAG分解及挥发物合成中的功能。综上，本文的研究从分子水平鉴定了番茄中亲脂化合物的遗传结构基础，同时揭示了甘油骨架上脂肪酸的释放对于下游挥发物的合成影响巨大。

p.s.导入系（introgression lines; ILs）：利用多代回交和分子标记辅助选择构建的永久定位群体，是进行QTL遗传分析的理想材料。

回交重组自交系（backcross inbred lines; BIL）：通过两个亲本杂交得到F1，之后将得到的杂交后代不断的用亲本之一进行回交得到的群体。

近等基因系(Near Iso-genic Lines; NIL)：是指一组遗传背景相同或相近，而某个特定性状或其遗传基础有差异的一组品系。

通讯：Yariv Brotman (https://www.mpimp-golm.mpg.de/1965615/Yariv_Brotman)

个人简介：2001年，以色列Bar-Ilan大学，硕士；2005年，以色列Bar-Ilan大学，博士。

研究方向：代谢性状的遗传调控。

doi: https://doi.org/10.1016/j.molp.2018.06.003

Journal: Molecular Plant

First Published: 26 May, 2018

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