College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010018, China.
Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Advanced Technology of Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China.
G3 (Bethesda). 2024 Sep 4;14(9). doi: 10.1093/g3journal/jkae147.
Strigolactones (SLs), carotenoid-derived plant hormones, govern the growth and development of both monocotyledonous and dicotyledonous plants. DWARF27 (D27), a plastid-targeted protein located at the initiation site of the core pathway in SL synthesis, plays a crucial role in regulating plant tillering (branching). In rice (Oryza sativa) and wheat (Triticum aestivum), OsD27 and TaD27-B proteins modulate the number of plant tillers by participating in SL biosynthesis. Similarly, AtD27 in Arabidopsis thaliana is required for SL production and has a significant impact on phenotypic changes related to branching. At the same time, TaD27 in wheat has been confirmed as a functional orthologue of AtD27 in Arabidopsis, and both Psathyrostachys juncea and wheat belong to the Triticeae, so we speculate that PjD27 gene may also have the same function as AtD27 in Arabidopsis. In this study, we initially screened the PjD27 gene significantly associated with tillering regulation through transcriptome data analysis and subsequently validated its expression levels using qRT-PCR analysis. Furthermore, we conducted phylogenetic analysis using amino acid sequences from 41 species, including P. juncea, to identify closely related species of P. juncea. Here, we analyze the conservation of D27 protein among P. juncea, rice, wheat, and Arabidopsis and provide preliminary evidence suggesting that PjD27 protein is an orthologue of D27 protein in Arabidopsis. Through reverse genetics, we demonstrate the crucial role of PjD27 in regulating plant branching, establishing it as a functional orthologue of D27 in Arabidopsis. Furthermore, following transient expression in tobacco (Nicotiana tabacum), we demonstrate that the subcellular location of the PjD27 protein is consistent with the cellular location of TaD27-B in wheat. Quantitative analysis of SLs shows that PjD27 is a key gene regulating tillering (branching) by participating in SL biosynthesis. By elucidating the function of the PjD27 gene, our findings provide valuable genetic resources for new germplasm creation and improving grain yield in P. juncea.
独脚金内酯（SLs）是一种类胡萝卜素衍生的植物激素，调控单子叶和双子叶植物的生长和发育。DWARF27（D27）是一种定位于 SL 合成核心途径起始位点的质体靶向蛋白，在调控植物分蘖（分枝）方面发挥着关键作用。在水稻（Oryza sativa）和小麦（Triticum aestivum）中，OsD27 和 TaD27-B 蛋白通过参与 SL 生物合成来调节植物分蘖数。同样，拟南芥（Arabidopsis thaliana）中的 AtD27 对于 SL 的产生是必需的，并且对与分枝相关的表型变化有重大影响。同时，小麦中的 TaD27 已被证实是拟南芥中 AtD27 的功能同源物，并且冰草（Psathyrostachys juncea）和小麦都属于禾本科，因此我们推测 PjD27 基因可能也具有与拟南芥中 AtD27 相同的功能。在本研究中，我们首先通过转录组数据分析筛选出与分蘖调控显著相关的 PjD27 基因，随后使用 qRT-PCR 分析验证其表达水平。此外，我们还使用来自 41 个物种的氨基酸序列进行了系统发育分析，包括冰草，以鉴定与冰草密切相关的物种。在这里，我们分析了 D27 蛋白在冰草、水稻、小麦和拟南芥中的保守性，并提供了初步证据表明 PjD27 蛋白是拟南芥中 D27 蛋白的同源物。通过反向遗传学，我们证明了 PjD27 在调控植物分枝中的关键作用，确立了它是拟南芥中 D27 蛋白的功能同源物。此外，在烟草（Nicotiana tabacum）中进行瞬时表达后，我们证明了 PjD27 蛋白的亚细胞定位与小麦中 TaD27-B 的细胞定位一致。SLs 的定量分析表明，PjD27 通过参与 SL 生物合成是调节分蘖（分枝）的关键基因。通过阐明 PjD27 基因的功能，我们的研究结果为冰草新种质的创制和提高产量提供了有价值的遗传资源。
