INTRODUCTION Frost events lead to A$360 million of yield losses annually to the Australian wheat industry, making improvement of chilling and frost tolerance an important trait for breeding. OBJECTIVES This study aimed to use metabolomics and lipidomics to explore genetic variation in acclimation potential to chilling and to identify metabolite markers for chilling tolerance in wheat. METHODS We established a controlled environment screening assay that is able to reproduce field rankings of wheat germplasm for chilling and frost tolerance. This assay, together with targeted metabolomics and lipidomics approaches, were used to compare metabolite and lipid levels in flag leaves of two wheat varieties with contrasting chilling tolerance. RESULTS The sensitive variety Wyalkatchem showed a strong reduction in amino acids after the first cold night, followed by accumulation of osmolytes such as fructose, glucose, putrescine and shikimate over a 4-day period. Accumulation of osmolytes is indicative of acclimation to water stress in Wyalkatchem. This response was not observed for tolerant variety Young. The two varieties also displayed significant differences in lipid accumulation. Variation in two lipid clusters, resulted in a higher unsaturated to saturated lipid ratio in Young after 4 days cold treatment and the lipids PC(34:0), PC(34:1), PC(35:1), PC(38:3), and PI(36:4) were the main contributors to the unsaturated to saturated ratio change. This indicates that Young may have superior ability to maintain membrane fluidity following cold exposure, thereby avoiding membrane damage and water stress observed for Wyalkatchem. CONCLUSION Our study suggests that metabolomics and lipidomics markers could be used as an alternative phenotyping method to discriminate wheat varieties with differences in cold acclimation.

中文翻译：

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使用靶向代谢组和脂质组分析对小麦生殖阶段的寒冷和霜冻耐受性进行表型分析。

简介 霜冻事件每年给澳大利亚小麦产业造成 3.6 亿澳元的产量损失，因此提高耐寒性和耐霜性成为育种的重要特性。目的本研究旨在利用代谢组学和脂质组学来探索小麦低温适应潜力的遗传变异，并鉴定小麦耐冷性的代谢标记。方法我们建立了一种受控环境筛选试验，能够重现小麦种质抗寒和抗冻性的田间排名。该测定与靶向代谢组学和脂质组学方法一起用于比较两个具有对比耐冷性的小麦品种旗叶的代谢和脂质水平。结果 敏感品种 Wyalkatchem 在第一个寒冷的夜晚后表现出氨基酸的强烈减少，随后在 4 天的时间里果糖、葡萄糖、腐胺和莽草酸等渗透物的积累。渗透剂的积累表明怀尔卡彻姆已经适应了水分胁迫。对于耐受性品种 Young，没有观察到这种反应。这两个品种在脂质积累方面也表现出显着差异。两个脂质簇的变化导致在 4 天冷处理后 Young 中不饱和脂质与饱和脂质的比例较高，脂质 PC(34:0)、PC(34:1)、PC(35:1)、PC(38:1) 3）和PI（36：4）是不饱和与饱和比率变化的主要贡献者。这表明 Young 在冷暴露后可能具有维持膜流动性的卓越能力，从而避免了 Wyalkatchem 观察到的膜损伤和水分胁迫。结论我们的研究表明，代谢组学和脂质组学标记可以作为替代表型分析方法来区分具有冷驯化差异的小麦品种。