Qin Dandan D, Liu Rui, Xu Fuchao, Dong Guoqing, Xu Qing, Peng Yanchun, Xu Le, Cheng Hongna, Guo Ganggang, Dong Jing, Li Chengdao
Institute of Food Crops, Hubei Academy of Agricultural Sciences, Hubei, Wuhan, China.
Hubei Key Laboratory of Food Crop Germplasm and Genetic Improvement, Hubei, Wuhan, China.
Front Plant Sci. 2023 Jul 6;14:1189743. doi: 10.3389/fpls.2023.1189743. eCollection 2023.
Multiple nodes and dwarf mutants in barley are a valuable resource for identifying genes that control shoot branching, vegetative growth and development.
In this study, physiological, microscopic and genetic analysis were conducted to characterize and fine-map the underling gene of a barley mutant with Multiple Stem Nodes and Spikes and Dwarf (), which was selected from EMS- and Co-treated barley . Edamai 934.
The mutant had more stem nodes, lower plant height and a shorter plastochron than Edamai 934. Moreover, the mutant had two or more spikes on each tiller. Microscopic analysis showed that the dwarf phenotype of resulted from reduced cell lengths and cell numbers in the stem. Further physiological analysis showed that was GA-deficient, with its plant height increasing after external GA application. Genetic analysis revealed that a single recessive nuclear gene, namely, Hv, controlled the phenotype. Using a segregating population derived from Harrington and the mutant, Hv was fine-mapped on chromosome 5H in a 200 kb interval using bulked segregant analysis (BSA) coupled with RNA-sequencing (BSR-seq), with a C-T substitution in the exon of HvTCP25 co-segregating with the phenotype. RNA-seq analysis showed that a gene encoding gibberellin 2-oxidase 8, a negative regulator of GA biosynthesis, was upregulated in the mutant. Several known genes related to inflorescence development that were also upregulated and enriched in the mutant. Collectively, we propose that Hv regulates the plastochron and morphology of reproductive organs, likely by coordinating GA homeostasis and changed expression of floral development related genes in barley. This study offers valuable insights into the molecular regulation of barley plant architecture and inflorescence development.
大麦中的多个节和矮化突变体是鉴定控制茎分枝、营养生长和发育基因的宝贵资源。
本研究对从甲基磺酸乙酯（EMS）和钴（Co）处理的大麦品种“Edamai 934”中筛选出的一个具有多个茎节、多个穗且矮化的大麦突变体进行了生理、显微和遗传分析，以对其潜在基因进行表征和精细定位。
该突变体比“Edamai 934”具有更多的茎节、更低的株高和更短的出叶间隔。此外，突变体每个分蘖上有两个或更多的穗。显微分析表明，该突变体的矮化表型是由于茎中细胞长度和细胞数量减少所致。进一步的生理分析表明，该突变体缺乏赤霉素（GA），外源施用GA后其株高增加。遗传分析显示，一个单隐性核基因Hv控制该突变体表型。利用来自“Harrington”和该突变体的分离群体，通过混合分离群体分析（BSA）结合RNA测序（BSR-seq），将Hv精细定位在5H染色体上200 kb的区间内，HvTCP25外显子中的一个C-T替换与该突变体表型共分离。RNA测序分析表明，一个编码GA生物合成负调控因子赤霉素2-氧化酶8的基因在该突变体中上调。几个与花序发育相关的已知基因在该突变体中也上调并富集。总体而言，我们提出Hv可能通过协调GA稳态和改变大麦中花发育相关基因的表达来调节出叶间隔和生殖器官的形态。本研究为大麦植株结构和花序发育的分子调控提供了有价值的见解。
