Chilling and frost conditions impose major yield restraints to wheat crops in Australia and other temperate climate regions. Unpredictability and variability of field frost events are major impediments for cold tolerance breeding. Metabolome and lipidome profiling were used to compare the cold response in spikes of cold-tolerant Young and sensitive variety Wyalkatchem at the young microspore (YM) stage of pollen development. We aimed to identify metabolite markers that can reliably distinguish cold-tolerant and sensitive wheat varieties for future cold-tolerance phenotyping applications. We scored changes in spike metabolites and lipids for both varieties during cold acclimation after initial and prolonged exposure to combined chilling and freezing cycles (1 and 4 days, respectively) using controlled environment conditions. The two contrasting wheat varieties showed qualitative and quantitative differences in primary metabolites involved in osmoprotection, but differences in lipid accumulation most distinctively separated the cold response of the two wheat lines. These results resemble what we previously observed in flag leaves of the same two wheat varieties. The fact that this response occurs in tissue types with very different functions indicates that chilling and freezing tolerance in these wheat lines is associated with re-modelling of membrane lipid composition to maintain membrane fluidity.

中文翻译：

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利用目标代谢组和脂质组分析对年轻的小孢子期小麦穗的低温和冷冻反应进行表型分析。

寒冷和霜冻条件严重限制了澳大利亚和其他温带气候区的小麦收成。田间霜冻事件的不可预测性和可变性是耐寒育种的主要障碍。代谢组和脂质组分析用于比较花粉发育年轻小孢子（YM）阶段耐寒年轻品种和敏感品种Wyalkatchem的峰值中的冷响应。我们旨在鉴定能够可靠地区分耐寒和敏感小麦品种的代谢物标记物，以用于未来的耐寒表型应用。在受控环境条件下，在最初和长时间暴露于组合的冷藏和冷冻周期（分别为1天和4天）后，我们在冷驯化期间对两个品种的峰值代谢物和脂质的变化进行了评分。两种相反的小麦品种显示出与渗透保护有关的主要代谢产物在质量和数量上的差异，但脂质积累的差异最明显地将两种小麦品系的冷响应区分开。这些结果类似于我们先前在相同的两个小麦品种的旗叶中观察到的结果。在具有不同功能的组织类型中发生这种反应的事实表明，这些小麦品系的耐冷性和耐冻性与膜脂质组成的重塑有关，以维持膜的流动性。这些结果类似于我们先前在相同的两个小麦品种的旗叶中观察到的结果。在具有不同功能的组织类型中发生这种反应的事实表明，这些小麦品系的耐冷性和耐冻性与膜脂质组成的重塑有关，以维持膜的流动性。这些结果类似于我们先前在相同的两个小麦品种的旗叶中观察到的结果。这种反应发生在功能非常不同的组织类型中的事实表明，这些小麦品系的耐冷性和耐冻性与膜脂质组成的重塑有关，以维持膜的流动性。