Abstract
BackgroundThe 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.ResultsHere, 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.ConclusionsOverall, the rgb1 mutants provide an ideal material for exploring the molecular mechanism underlying rice seedling formation during early postgermination development by G proteins.Significance statementThe heterotrimeric G protein β subunit RGB1 acts as a crucial factor in promoting early postgermination seedling development in rice.
Highlights
The heterotrimeric G protein β subunit RGB1 plays an important role in plant growth and development
The results suggest that RGB1 is an important factor in promoting seedling growth and development during early postgermination in rice
Identification and characterization of rgb1 mutants To identify the lethal stage of the rgb1 mutants and explore the exact function of RGB1, the CRISPR/Cas9 genome editing system was used to knock out RGB1 in the ‘Zhonghua11’ background (Fig. 1a)
Summary
The heterotrimeric G protein β subunit RGB1 plays an important role in plant growth and development. The molecular mechanisms underlying the regulation of rice growth by RGB1 remain elusive. G proteins play crucial roles as signal transducers in the regulation of a variety of growth and development processes in higher eukaryotes. Heterotrimeric G proteins, which are composed of α, β, and γ subunits, generally refer to the G proteins In contrast to those in humans, G protein subunits in plants are simple and are usually encoded by single gene or a few genes. The GPA1 and AGB1 subunits are encoded by a single gene each, while Gγ1, Gγ2, Gao et al Rice (2019) 12:53 and in transgenic plants indicate that G proteins mediate multiple developmental processes (Urano et al 2013). The exact function of RGB1 remains elusive in rice
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