Table_1_β-diketone accumulation in response to drought stress is weakened in modern bread wheat varieties (Triticum aestivum L.).xlsx

Cuticular waxes coating leaf surfaces can help plants tolerate drought events by reducing non-stomatal water loss. Despite their role in drought tolerance, little is known about how cuticular wax composition has changed during breeding in Canadian bread wheat (Triticum aestivum L.) varieties. To fill in this gap, flag leaves of the Canadian Heritage Bread Wheat Panel, which include 30 varieties released between 1842 and 2018, were surveyed to determine if and how cuticular wax composition in wheat has changed at two breeding ecozones over this period. Following this, a subset of varieties was subjected to drought conditions to compare their responses. As expected, modern varieties outperformed old varieties with a significantly larger head length and reaching maturity earlier. Yet, when challenged with drought, old varieties were able to significantly increase the accumulation of β-diketones to a higher extent than modern varieties. Furthermore, RNAseq was performed on the flag leaf of four modern varieties to identify potential markers that could be used for selection of higher accumulation of cuticular waxes. This analysis revealed that the W1 locus is a good candidate for selecting higher accumulation of β-diketones. These findings indicate that the variation in cuticular waxes upon drought could be further incorporated in breeding of future bread wheat varieties.

覆盖于叶片表面的表皮蜡质（cuticular waxes）可通过减少非气孔水分流失，帮助植物抵御干旱胁迫。尽管表皮蜡质在植物耐旱性中发挥关键作用，但目前对于加拿大面包小麦（Triticum aestivum L.）品种的育种过程中其表皮蜡质组成的演化规律仍知之甚少。为填补这一研究空白，本研究针对由1842年至2018年间育成的30个品种组成的加拿大传统面包小麦品种群体（Canadian Heritage Bread Wheat Panel）的旗叶（flag leaf）展开检测，以明确该时段内两个育种生态区中小麦表皮蜡质组成的变化模式与具体特征。在此基础上，选取部分品种进行干旱胁迫处理，对比二者的耐旱响应差异。正如预期，现代品种表现更优异：其穗长显著更长，且成熟更早。然而在遭遇干旱胁迫时，老品种的β-二酮（β-diketones）积累量的提升幅度显著高于现代品种。此外，本研究对4个现代品种的旗叶进行RNA测序（RNAseq），以筛选可用于表皮蜡质高积累性状选育的潜在分子标记。分析结果显示，W1基因座（W1 locus）是筛选高β-二酮积累量的优良候选靶点。本研究结果表明，干旱胁迫下表皮蜡质的变异特征可进一步应用于未来面包小麦的育种改良工作中。