Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada.
Morden Research and Development Center, Agriculture and Agri-Food Canada, Morden, Manitoba, Canada.
Plant Cell Environ. 2021 Jul;44(7):2230-2244. doi: 10.1111/pce.13963. Epub 2020 Dec 9.
Through a combination of physiological, pharmacological, molecular and targeted metabolomics approaches, we showed that retention of wheat (Triticum aestivum L.) seed dormancy levels induced by low and high seed development temperatures during post-desiccation phases is associated with modulation of gibberellin (GA) level and seed responsiveness to abscisic acid (ABA) and GA via expression of TaABI5 and TaGAMYB, respectively. Dormancy retention during imbibition, however, is associated with modulations of both ABA level and responsiveness via expression of specific ABA metabolism (TaNCED2 and TaCYP707A1) and signalling (TaPYL2, TaSnRK2, TaABI3, TaABI4 and TaABI5) genes, and alterations of GA levels and responsiveness through expression of specific GA biosynthesis (TaGA20ox1, TaGA20ox2 and TaGA3ox2) and signalling (TaGID1 and TaGID2) genes, respectively. Expression patterns of GA signalling genes, TaRHT1 and TaGAMYB, lacked positive correlation with that of GA regulated genes and dormancy level observed in seeds developed at the two temperatures, implying their regulation at post-transcriptional level. Our results overall implicate that a shift in ABA/GA balance underlies retention of dormancy levels induced by seed development temperature during post-desiccation and imbibition phases. Consistently, genes regulated by ABA and GA during imbibition overlapped with those differentially expressed between imbibed seeds developed at the two temperatures and mediate different biological functions.
通过生理、药理学、分子和靶向代谢组学方法的结合，我们表明，在脱水后阶段，低温和高温种子发育对小麦（Triticum aestivum L.）种子休眠水平的诱导保留与赤霉素（GA）水平的调节以及通过 TaABI5 和 TaGAMYB 的表达对脱落酸（ABA）和 GA 的种子响应有关。然而，在吸胀过程中保留休眠与 ABA 水平和通过表达特定的 ABA 代谢（TaNCED2 和 TaCYP707A1）和信号转导（TaPYL2、TaSnRK2、TaABI3、TaABI4 和 TaABI5）基因的响应有关，以及通过表达特定的 GA 生物合成（TaGA20ox1、TaGA20ox2 和 TaGA3ox2）和信号转导（TaGID1 和 TaGID2）基因的响应有关，GA 水平和响应性的变化。GA 信号转导基因 TaRHT1 和 TaGAMYB 的表达模式与在两种温度下发育的种子中观察到的 GA 调节基因和休眠水平缺乏正相关，这表明它们在转录后水平受到调节。我们的研究结果总体表明，在脱水后和吸胀阶段，种子发育温度诱导的休眠水平保留的 ABA/GA 平衡的转变。一致地，在吸胀过程中由 ABA 和 GA 调节的基因与在两种温度下发育的吸胀种子之间差异表达的基因重叠，并介导不同的生物学功能。
