INTRODUCTION Lipids are a diverse group of macromolecules that occur in rice grains and are known to impact rice grain properties. Identifying the relationships between specific lipids and traits of quality is important to improve varietal selection for high quality rice. OBJECTIVES Using untargeted lipidomics, this study aims to understand the role of lipids on different traits of quality by identifying the genotypic effect of lipids and their impact on traits of cooking and eating quality of a rice mapping population. METHODS Lipids from milled rice grains of three sets of rice samples were screened by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) in the positive ionisation mode. Lipid features were putatively identified using analytical standards and online databases. Multivariate statistics were carried out to identify the lipid profile of varieties across three experiments. Correlation analysis was carried out between lipid features and 12 quality traits across a rice mapping population that segregates for grain physical and texture-associated traits. RESULTS Thousands of features in rice grain lipids were detected, and were grouped into six categories-fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterol lipids and prenol lipids. A strong genotypic basis for the lipid profile was observed among the four varieties grown under five nitrogen treatments. Clear differentiation in lipid profiles between waxy and non-waxy rice was observed. Strong correlations were observed for putative lipids that form the amylose-lipid complex and with amylose content and viscosity parameters. CONCLUSIONS This study demonstrates the strength of untargeted lipidomics in putatively determining features that differentiate varieties from each other, and reveals the role of specific lipids on the physical and textural quality of rice.

中文翻译：

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脂质组学揭示了稻米品质性状之间的关联。

引言脂质是存在于稻米中的各种各样的大分子，已知会影响稻米的特性。鉴定特定脂质与品质性状之间的关系对于提高优质水稻的品种选择非常重要。目的使用非靶向脂质组学，本研究旨在通过鉴定脂质的基因型效应及其对水稻作图人群的烹饪和饮食质量特征的影响，来了解脂质在不同品质特征上的作用。方法采用正电离模式，通过超高效液相色谱-质谱法（UPLC-MS）筛选三套大米样品的碾米颗粒中的脂质。使用分析标准和在线数据库推定脂质特征。在三个实验中进行了多元统计，以鉴定品种的脂质谱。在水稻作图群体中，其脂质特征与12个品质性状之间进行了相关性分析，这些品质性状针对谷物的物理和纹理相关性状进行了分离。结果检测到水稻籽粒脂质的数千个特征，并将其分为六类：脂肪酰基，甘油脂质，甘油磷脂，鞘脂，固醇脂质和prenol脂质。在五个氮处理下生长的四个品种中，观察到了脂质分布的强大的基因型基础。观察到蜡质和非蜡质水稻的脂类分布明显不同。观察到形成直链淀粉-脂质复合物的直链淀粉含量与粘度参数之间存在强相关性。