Division of Plant Sciences, School of Life Sciences, The University of Dundee at The James Hutton Institute, Invergowrie, Dundee DD2 5DA, Scotland.
Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, Scotland.
Development. 2019 Jun 12;146(11):dev170373. doi: 10.1242/dev.170373.
Many plants dramatically elongate their stems during flowering, yet how this response is coordinated with the reproductive phase is unclear. We demonstrate that microRNA (miRNA) control of () is required for rapid, complete elongation of stem internodes in barley, especially of the final 'peduncle' internode directly underneath the inflorescence. Disrupted miR172 targeting of in the barley mutant caused lower mitotic activity, delayed growth dynamics and premature lignification in the peduncle leading to fewer and shorter cells. Stage- and tissue-specific comparative transcriptomics between and its parent cultivar showed reduced expression of proliferation-associated genes, ectopic expression of maturation-related genes and persistent, elevated expression of genes associated with jasmonate and stress responses. We further show that applying methyl jasmonate (MeJA) phenocopied the stem elongation of , and that itself was hypersensitive to inhibition by MeJA but less responsive to promotion by gibberellin. Taken together, we propose that miR172-mediated restriction of may modulate the jasmonate pathway to facilitate gibberellin-promoted stem growth during flowering.
许多植物在开花期会显著延长茎的长度，但这种反应如何与生殖阶段相协调还不清楚。我们证明，miRNA 对 () 的控制是大麦中茎节快速、完全伸长所必需的，特别是在花序下直接的最后一个“花梗”节间。在 大麦突变体中，miR172 对 的靶向破坏导致花梗中细胞分裂活性降低、生长动态延迟和过早木质化，导致细胞数量减少和变短。在突变体与其亲本品种之间进行的阶段和组织特异性比较转录组学研究表明，与增殖相关的基因表达减少，成熟相关基因的异位表达，以及与茉莉酸和应激反应相关的基因持续上调和升高。我们进一步表明，施用茉莉酸甲酯 (MeJA) 可模拟 的茎伸长，而 本身对 MeJA 的抑制作用敏感，但对赤霉素的促进作用反应较少。综上所述，我们提出 miR172 介导的对 的限制可能调节茉莉酸途径，以促进开花期间赤霉素促进的茎生长。
