Seed-specific down-regulation of AtCESA1 and AtCESA9, which encode cellulose synthase subunits, differentially affects seed storage compound accumulation in Arabidopsis. High amounts of cellulose can negatively affect crop seed quality, and, therefore, diverting carbon partitioning from cellulose to oil, protein and/or starch via molecular breeding may improve seed quality. To determine the effect of seed cellulose content reduction on levels of storage compounds, Arabidopsis thaliana CELLULOSE SYNTHASE1 (AtCESA1) and AtCESA9 genes, which both encode cellulose synthase subunits, were individually down-regulated using seed-specific intron-spliced hairpin RNA (hpRNAi) constructs. The selected seed-specific AtCESA1 and AtCESA9 Arabidopsis RNAi lines displayed reduced cellulose contents in seeds, and exhibited no obvious visual phenotypic growth defects with the exception of a minor effect on early root development in AtCESA1 RNAi seedlings and early hypocotyl elongation in the dark in both types of RNAi line. The seed-specific down-regulation of AtCESA9 resulted in a reduction in seed weight compared to empty vector controls, which was not observed in AtCESA1 RNAi lines. In terms of effects on carbon partitioning, AtCESA1 and AtCESA9 RNAi lines exhibited distinct effects. The down-regulation of AtCESA1 led to a ~ 3% relative increase in seed protein content (P = 0.04) and a ~ 3% relative decrease in oil content (P = 0.02), but caused no alteration in soluble glucose levels. On the contrary, AtCESA9 RNAi lines did not display a significant reduction in seed oil, protein or soluble glucose content. Taken together, our results indicate that the seed-specific down-regulation of AtCESA1 causes alterations in seed storage compound accumulation, while the effect of AtCESA9 on carbon partitioning is absent or minor in Arabidopsis.

中文翻译：

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拟南芥纤维素合成酶 1 或 9 的种子特异性下调降低了种子纤维素含量并不同地影响碳分配。

编码纤维素合酶亚基的 AtCESA1 和 AtCESA9 的种子特异性下调对拟南芥种子贮藏化合物的积累有不同的影响。大量的纤维素会对作物种子质量产生负面影响，因此，通过分子育种将碳分配从纤维素转移到油、蛋白质和/或淀粉可以提高种子质量。为了确定种子纤维素含量降低对储存化合物水平的影响，使用种子特异性内含子剪接发夹 RNA (hpRNAi) 分别下调编码纤维素合酶亚基的拟南芥 CELLULOSE SYNTHASE1 (AtCESA1) 和 AtCESA9 基因结构体。选定的种子特异性 AtCESA1 和 AtCESA9 拟南芥 RNAi 系显示出种子中纤维素含量降低，并且没有表现出明显的视觉表型生长缺陷，除了对 AtCESA1 RNAi 幼苗的早期根发育的轻微影响和两种类型的 RNAi 系在黑暗中的早期下胚轴伸长。与空载体对照相比，AtCESA9 的种子特异性下调导致种子重量减少，这在 AtCESA1 RNAi 系中未观察到。在对碳分配的影响方面，AtCESA1 和 AtCESA9 RNAi 系表现出不同的影响。AtCESA1 的下调导致种子蛋白质含量相对增加约 3%（P = 0.04），油含量相对减少约 3%（P = 0.02），但未引起可溶性葡萄糖水平的改变。相反，AtCESA9 RNAi 系没有显示出种子油、蛋白质或可溶性葡萄糖含量的显着降低。综合起来，