Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
Horticultural Sciences, Plant Innovation Center, University of Florida, Gainesville, FL, USA.
Mol Plant. 2018 Sep 10;11(9):1147-1165. doi: 10.1016/j.molp.2018.06.003. Epub 2018 Jun 28.
To gain insight into the genetic regulation of lipid metabolism in tomato, we conducted metabolic trait loci (mQTL) analysis following the lipidomic profiling of fruit pericarp and leaf tissue of the Solanum pennellii introgression lines (IL). To enhance mapping resolution for selected fruit-specific mQTL, we profiled the lipids in a subset of independently derived S. pennellii backcross inbred lines, as well as in a near-isogenic sub-IL population. We identified a putative lecithin:cholesterol acyltransferase that controls the levels of several lipids, and two members of the class III lipase family, LIP1 and LIP2, that were associated with decreased levels of diacylglycerols (DAGs) and triacylglycerols (TAGs). Lipases of this class cleave fatty acids from the glycerol backbone of acylglycerols. The released fatty acids serve as precursors of flavor volatiles. 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. Taken together, our study extensively characterized the genetic architecture of lipophilic compounds in tomato and demonstrated at molecular level that release of free fatty acids from the glycerol backbone can have a major impact on downstream volatile synthesis.
为了深入了解番茄脂质代谢的遗传调控，我们对 Solanum pennellii 渐渗系果皮和叶组织的脂质组学图谱进行了代谢性状位点 (mQTL) 分析。为了提高选定果实特异性 mQTL 的图谱分辨率，我们对一组独立衍生的 S. pennellii 回交自交系以及近等基因亚系群体中的脂质进行了分析。我们鉴定出一种可能的卵磷脂：胆固醇酰基转移酶，它控制着几种脂质的水平，以及属于第三类脂肪酶家族的两个成员 LIP1 和 LIP2，它们与二酰基甘油 (DAG) 和三酰基甘油 (TAG) 的水平降低有关。这类脂肪酶从酰基甘油的甘油主链上切割脂肪酸。释放的脂肪酸可作为风味挥发物的前体。我们表明，LIP1 的表达与脂肪酸衍生的挥发性水平相关。我们还使用转基因植物进一步证实了 LIP1 在 TAG 和 DAG 分解以及挥发性合成中的功能。总之，我们的研究广泛描述了番茄亲脂化合物的遗传结构，并在分子水平上证明了从甘油主链上释放游离脂肪酸对下游挥发性合成有重大影响。
