College of Tea Sciences, Guizhou University, 550025, Guiyang, China; The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Regions (Ministry of Education), Guizhou University, Guiyang, 550025, China.
The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Regions (Ministry of Education), Guizhou University, Guiyang, 550025, China.
Plant Sci. 2022 Jul;320:111201. doi: 10.1016/j.plantsci.2022.111201. Epub 2022 Jan 31.
To explore the molecular mechanisms underlying plant height regulation, we isolated and characterized a stably inherited semi-dwarf mutant bgsd-2 from the ethane methyl sulfonate (EMS) mutant progeny of 'Ping Tang Wild-type (PTWT)', a rice (Oryza sativa ssp. japonica) landrace in Guizhou. Transcriptome sequencing and qRT-PCR analyses showed that a number of cellulose and lignin-related genes involved in cell wall biogenesis were substantially downregulated in bgsd-2. MutMap-based cloning revealed the occurrence of a single amino acid substitution in the LOC_Os01g51300 gene, belonging to the MSI1 (multicopy suppressor of IRA1) member OsRBAP1. The bgsd-2 mutation occurred in the 3rd exon of OsRBAP1, resulting in a nonsense mutation of a codon shift from glycine (G) to glutamic acid (E) at residue 65. Protein localization analysis uncovered that the OsRBAP1 gene encodes a nuclear-localized protein and that the mutation in bgsd-2 may affect the stability of the OsRBAP1 protein. The CRISPR/Cas9 system was used to switch off OsRBAP1 in PTWT to obtain the knockout mutant osrbap1, which exhibited a severe reduction in height and fertility. Cytological observations suggest that the dwarfism of osrabp1 may be caused by reduced cell size and numbers, and that male sterility may be due to abnormal microspore development. Transcriptome analysis revealed that OsRBAP1 defects can repress the expression of numerous essential genes, which regulate multiple developmental processes in plants. Altogether, our results suggest that OsRBAP1 plays an important role in the regulation of rice height and spikelet fertility.
为了探究植物株高调控的分子机制，我们从贵州地方品种‘平塘野生稻（PTWT）’的乙硫氨酸亚砜（EMS）诱变后代中分离并鉴定了一个稳定遗传的半矮秆突变体 bgsd-2。转录组测序和 qRT-PCR 分析表明，细胞壁生物合成中许多与纤维素和木质素相关的基因在 bgsd-2 中显著下调。基于 MutMap 的克隆揭示，LOC_Os01g51300 基因发生了单个氨基酸替换，该基因属于 MSI1（IRA1 的多拷贝抑制子）成员 OsRBAP1。bgsd-2 突变发生在 OsRBAP1 的第 3 个外显子中，导致密码子从甘氨酸（G）到谷氨酸（E）的移码突变，在第 65 位氨基酸残基上。蛋白定位分析表明，OsRBAP1 基因编码一个核定位蛋白，bgsd-2 中的突变可能影响 OsRBAP1 蛋白的稳定性。我们利用 CRISPR/Cas9 系统在 PTWT 中敲除 OsRBAP1 获得了敲除突变体 osrbap1，其表现出严重的矮化和育性降低。细胞学观察表明，osrabp1 的矮化可能是由于细胞大小和数量减少所致，雄性不育可能是由于小孢子发育异常所致。转录组分析表明，OsRBAP1 缺陷可以抑制许多必需基因的表达，这些基因调控植物的多个发育过程。总之，我们的研究结果表明，OsRBAP1 在水稻株高和小穗育性调控中发挥重要作用。
