NAC transcription factors (TFs) are known for their role in development and stress. This article attempts to functionally validate the role of rice SS1/ ONAC025 (LOC_Os11g31330) during seed development. The gene is seed‐specific and its promoter directs reporter expression in the developing endosperm and embryo in rice transgenic plants. Furthermore, rice transgenic plants ectopically expressing SS1/ ONAC025 have a plantlet lethal phenotype with hampered vegetative growth, but increased tillers and an altered shoot apical meristem structure. The vegetative cells of these plantlets are filled with distinct starch granules. RNAseq analysis of two independent plantlets reveals the differential expression of reproductive and photosynthetic genes. A comparison with seed development transcriptome indicates differential regulation of many seed‐related genes by SS1/ ONAC025. Genes involved in starch biosynthesis, especially amylopectin and those encoding seed storage proteins, and regulating seed size are also differentially expressed. In conjunction, SS1/ ONAC025 shows highest expression in japonica rice. As a TF, SS1/ ONAC025 is a transcriptional repressor localized to endoplasmic reticulum and nucleus. The article shows that SS1/ ONAC025 is a seed‐specific gene promoting grain filling in rice, and negatively affecting vegetative growth.

中文翻译：

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SUPER STARCHY1 / ONAC025参与稻谷馅

NAC转录因子（TFs）在发育和压力中的作用众所周知。本文试图在功能上验证水稻SS1 / ONAC025（LOC_Os11g31330）在种子发育过程中的作用。该基因具有种子特异性，其启动子指导记者在水稻转基因植物的发育中的胚乳和胚中表达。此外，异位表达SS1 / ONAC025的水稻转基因植物植株具有致命的表型，营养生长受阻，但分till增加且茎尖分生组织结构发生改变。这些小植株的营养细胞充满了不同的淀粉颗粒。对两个独立小植株的RNAseq分析揭示了生殖和光合基因的差异表达。与种子发育转录组的比较表明SS1 / ONAC025对许多种子相关基因的差异调节。与淀粉生物合成有关的基因，特别是支链淀粉和编码种子贮藏蛋白的基因，以及调节种子大小的基因，也有差异表达。结合起来，SS1 / ONAC025在粳稻中表达最高白饭。作为TF，SS1 / ONAC025是位于内质网和细胞核的转录阻遏物。该文章显示SS1 / ONAC025是一种种子特异性基因，可促进水稻的籽粒填充，并对营养生长产生负面影响。