Development of a Model System to Identify Differences in Spring and Winter Oat

Our long-term goal is to develop a Swedish winter oat (Avena sativa). To identify molecular differences that correlate with winter hardiness, a winter oat model comprising of both non-hardy spring lines and winter hardy lines is needed. To achieve this, we selected 294 oat breeding lines, originating from various Russian, German, and American winter oat breeding programs and tested them in the field in south- and western Sweden. By assaying for winter survival and agricultural properties during four consecutive seasons, we identified 14 breeding lines of different origins that not only survived the winter but also were agronomically better than the rest. Laboratory tests including electrolytic leakage, controlled crown freezing assay, expression analysis of the AsVrn1 gene and monitoring of flowering time suggested that the American lines had the highest freezing tolerance, although the German lines performed better in the field. Finally, six lines constituting the two most freezing tolerant lines, two intermediate lines and two spring cultivars were chosen to build a winter oat model system. Metabolic profiling of non-acclimated and cold acclimated leaf tissue samples isolated from the six selected lines revealed differential expression patterns of 245 metabolites including several sugars, amino acids, organic acids and 181 hitherto unknown metabolites. The expression patterns of 107 metabolites showed significant interactions with either a cultivar or a time-point. Further identification, characterisation and validation of these metabolites will lead to an increased understanding of the cold acclimation process in oats. Furthermore, by using the winter oat model system, differential sequencing of crown mRNA populations would lead to identification of various biomarkers to facilitate winter oat breeding.

本研究的长期目标为培育瑞典冬燕麦（Avena sativa）。为鉴定与抗寒性相关的分子差异，亟需构建兼具非抗寒春性品系与抗寒冬性品系的冬燕麦模型体系。为此，我们选取了源自俄罗斯、德国及美国多个冬燕麦育种项目的294份燕麦育种品系，并在瑞典南部与西部的田间开展试验。通过连续四个季节对越冬存活率与农艺性状进行测定，我们筛选出14份不同来源的育种品系，这些品系不仅成功越冬，且综合农艺性状优于其余供试材料。实验室检测项目包括电解质渗漏率测定、受控冠部冷冻试验、AsVrn1基因表达分析以及开花期观测，结果显示美国品系的冷冻耐受性最强，而德国品系在田间表现更优。最终，我们选取了6份品系用于构建冬燕麦模型体系，其中包含2份冷冻耐受性最强的品系、2份中间型品系以及2份春性燕麦品种。对选取的6份品系的非驯化与冷驯化叶片组织样本进行代谢组分析，共鉴定出245种差异表达代谢物，涵盖糖类、氨基酸、有机酸等类别，其中181种为迄今未被报道的代谢物。其中107种代谢物的表达模式与品种或采样时间点存在显著交互作用。对这些代谢物开展进一步的鉴定、表征与验证工作，将有助于深化我们对燕麦冷驯化过程的认知。此外，依托该冬燕麦模型体系对冠部mRNA群体进行差异测序，将有助于筛选出多种生物标志物，从而推动冬燕麦育种工作。