Background

The heterotrimeric G protein β subunit RGB1 plays an important role in plant growth and development. However, the molecular mechanisms underlying the regulation of rice growth by RGB1 remain elusive.

Results

Here, the rgb1 mutants rgb1–1 (+ 1 bp), rgb1–2 (− 1 bp), and rgb1–3 (− 11 bp) were isolated using the CRISPR/Cas9 system, and they were arrested at 1 day after germination and ultimately exhibited seedling lethality. The dynamic anatomical characteristics of the embryos of the rgb1 seedlings and WT during early postgermination and according to TUNEL assays showed that the suppressed growth of the rgb1 mutants was caused by cell death. In addition to the limited shoot and root development, the development of the embryo shoot-root axis was suppressed in the rgb1 mutants. RGB1 was expressed mainly in the root epidermal and vascular tissues of the embryo. Moreover, transcript profiling analysis revealed that the expression of a large number of auxin-, cytokinin-, and brassinosteroid-inducible genes was upregulated or downregulated in the rgb1 mutant compared to the wild type during seedling development.

Conclusions

Overall, the rgb1 mutants provide an ideal material for exploring the molecular mechanism underlying rice seedling formation during early postgermination development by G proteins.

Significance statement

The heterotrimeric G protein β subunit RGB1 acts as a crucial factor in promoting early postgermination seedling development in rice.

中文翻译：

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异源三聚体 G 蛋白 β 亚基 RGB1 是水稻幼苗形成所必需的。

背景

异源三聚体G蛋白β亚基RGB1在植物生长发育中起重要作用。然而，RGB1调控水稻生长的分子机制仍然难以捉摸。

结果

在这里，使用 CRISPR/Cas9 系统分离了rgb1突变体rgb1-1 (+ 1 bp)、rgb1-2 (- 1 bp) 和rgb1-3 (- 11 bp)，它们在发芽后 1 天被捕获并最终表现出幼苗杀伤力。rgb1幼苗和 WT 在发芽后早期胚胎的动态解剖特征和根据 TUNEL 测定表明rgb1突变体的抑制生长是由细胞死亡引起的。除了有限的芽和根发育外，rgb1突变体中胚芽-根轴的发育受到抑制。RGB1主要在胚胎的根表皮和维管组织中表达。此外，转录谱分析表明，与野生型相比，rgb1突变体在幼苗发育过程中大量生长素、细胞分裂素和油菜素内酯诱导基因的表达上调或下调。

结论

总体而言，rgb1突变体为探索 G 蛋白在萌发后早期发育过程中水稻幼苗形成的分子机制提供了理想的材料。

意义陈述

异源三聚体 G 蛋白 β 亚基 RGB1 是促进水稻早期萌发后幼苗发育的关键因素。