Hormone-mediated growth dynamics of the barley pericarp as revealed by magnetic resonance imaging and transcript profiling
Hormone-mediated growth dynamics of the barley pericarp as revealed by magnetic resonance imaging and transcript profiling
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DOI：
10.1093/jxb/erv397
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发表时间：
2015-11-01
影响因子：
6.9
通讯作者：
Weschke, Winfriede
中科院分区：
文献类型：
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作者：
Pielot, Rainer;Kohl, Stefan;Weschke, Winfriede
母体果皮的形状影响谷物的质量和产量。通过磁共振成像（MRI）分析果皮生长，揭示大麦（Hordeum vulgare）果皮发育过程中流动水的拓扑图，并显示以特定时空模式主动伸长的组织区域。 MRI 信号和生长速率的相关分析表明，长度的生长是由背侧和侧向而不是腹侧区域介导的。厚度的增长与腹侧区域有关。从背侧生长转变为腹侧生长与 HD-ZipIII 和 Kanadi/Ettin 类型的轴向调节因子以及 NPH3 光感受器的差异表达相关，表明光介导的生长素重新分布。受精后 6 天 (DAF)，生长素在基部果皮中的水平达到最高水平，同时转录上调生长素转运和信号传导。赤霉素生物合成仅在后期转录上调，生物活性赤霉素的水平从 7 DAF 增加至 13 DAF，腹侧区域的水平高于背侧区域。与细胞扩张相关的差异基因表达表明与质外体酸化、壁松弛、糖裂解、水运输和细胞壁生物合成相关的基因。可能参与果皮延伸的候选基因通过其时间表达来区分，代表了负责背侧介导的早期长度生长或腹侧介导的晚期厚度生长的潜在亚型。
The shape of the maternal pericarp affects cereal grain mass and yield. Pericarp growth was analysed by magnetic resonance imaging (MRI), revealing topological maps of mobile water in developing pericarp of barley (Hordeum vulgare) and displaying tissue regions actively elongating in specific temporal-spatial patterns. Correlation analysis of MRI signals and growth rates reveals that growth in length is mediated by dorsal and also lateral rather than ventral regions. Growth in thickness is related to ventral regions. Switching from dorsal to ventral growth is associated with differential expression of axial regulators of the HD-ZipIII and Kanadi/Ettin types, and NPH3 photoreceptors, suggesting light-mediated auxin re-distribution. Auxin increases with the highest levels in the basal pericarp at 6 days after fertilization (DAF), together with transcriptionally up-regulated auxin transport and signalling. Gibberellin biosynthesis is transcriptionally up-regulated only later, and levels of bioactive gibberellins increase from 7 to 13 DAF, with higher levels in ventral than dorsal regions. Differential gene expression related to cell expansion indicates genes related to apoplast acidification, wall relaxation, sugar cleavage, water transport, and cell wall biosynthesis. Candidate genes potentially involved in pericarp extension are distinguished by their temporal expression, representing potential isoforms responsible for dorsal-mediated early growth in length or ventral-mediated late growth in thickness.