Roach Melissa, Arrivault Stéphanie, Mahboubi Amir, Krohn Nicole, Sulpice Ronan, Stitt Mark, Niittylä Totte
Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden.
Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, Germany.
J Exp Bot. 2017 Jun 15;68(13):3529-3539. doi: 10.1093/jxb/erx200.
The contribution of transcriptional and post-transcriptional regulation to modifying carbon allocation to developing wood of trees is not well defined. To clarify the role of transcriptional regulation, the enzyme activity patterns of eight central primary metabolism enzymes across phloem, cambium, and developing wood of aspen (Populus tremula L.) were compared with transcript levels obtained by RNA sequencing of sequential stem sections from the same trees. Enzymes were selected on the basis of their importance in sugar metabolism and in linking primary metabolism to lignin biosynthesis. Existing enzyme assays were adapted to allow measurements from ~1 mm3 sections of dissected stem tissue. These experiments provided high spatial resolution of enzyme activity changes across different stages of wood development, and identified the gene transcripts probably responsible for these changes. In most cases, there was a clear positive relationship between transcripts and enzyme activity. During secondary cell wall formation, the increases in transcript levels and enzyme activities also matched with increased levels of glucose, fructose, hexose phosphates, and UDP-glucose, emphasizing an important role for transcriptional regulation in carbon allocation to developing aspen wood. These observations corroborate the efforts to increase carbon allocation to wood by engineering gene regulatory networks.
转录调控和转录后调控对树木发育中木材碳分配的影响尚不明确。为了阐明转录调控的作用，我们比较了白杨（Populus tremula L.）韧皮部、形成层和发育中木材中八种主要初级代谢酶的酶活性模式，并将其与同一树木连续茎段RNA测序获得的转录水平进行了比较。这些酶是根据它们在糖代谢以及将初级代谢与木质素生物合成联系起来的重要性来选择的。现有的酶检测方法经过改进，以便能够对解剖后的茎组织约1立方毫米的切片进行测量。这些实验提供了木材发育不同阶段酶活性变化的高空间分辨率，并确定了可能导致这些变化的基因转录本。在大多数情况下，转录本与酶活性之间存在明显的正相关关系。在次生细胞壁形成过程中，转录水平和酶活性的增加也与葡萄糖、果糖、己糖磷酸酯和UDP - 葡萄糖水平的增加相匹配，这强调了转录调控在白杨发育中木材碳分配中的重要作用。这些观察结果证实了通过工程化基因调控网络来增加木材碳分配的努力。
