Bai Jiaxing, Guo Huijun, Xiong Hongchun, Xie Yongdun, Gu Jiayu, Zhao Linshu, Zhao Shirong, Ding Yuping, Liu Luxiang
State Key Laboratory of Crop Gene Resources and Breeding, National Engineering Laboratory of Crop Molecular Breeding, National Center of Space Mutagenesis for Crop Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
Mol Breed. 2024 Feb 2;44(2):12. doi: 10.1007/s11032-024-01450-3. eCollection 2024 Feb.
Tiller number greatly contributes to grain yield in wheat. Using ethylmethanesulfonate mutagenesis, we previously discovered the oligo-tillering mutant . The tiller number was significantly lower in than in the corresponding wild type from the early tillering stage until the heading stage. Compared to the wild type, the thousand-grain weight and grain length were increased by 15.41% and 31.44%, respectively, whereas the plant height and spike length were decreased by 26.13% and 37.25%, respectively. Transcriptomic analysis was conducted at the regreening and jointing stages to identify differential expressed genes (DEGs). Functional enrichment analysis with the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) databases showed differential expression of genes associated with ADP binding, transmembrane transport, and transcriptional regulation during tiller development. Differences in tiller number in led to the upregulation of genes in the strigolactone (SL) and abscisic acid (ABA) pathways. Specifically, the SL biosynthesis genes (), , , and () were upregulated by 3.37- to 8.23-fold; the SL signal transduction genes and were upregulated by 1.81- and 1.32-fold, respectively; the ABA biosynthesis genes -- () and were upregulated by 1.66- and 3.4-fold, respectively; and () and () genes were upregulated by 1.30- to 4.79-fold. This suggested that the tiller number reduction in was due to alterations in plant hormone pathways. Genes known to promote tillering growth were upregulated, whereas those known to inhibit tillering growth were downregulated. For example, (), which promotes tiller development, was upregulated by 8.23-fold in ; (), which inhibits tiller development, was downregulated by 1.74-fold. There were no significant differences in the expression levels of () or (), indicating that the tiller reduction in was not controlled by known genes. Our findings provide valuable data for subsequent research into the genetic bases and regulatory mechanisms of wheat tillering.
The online version contains supplementary material available at 10.1007/s11032-024-01450-3.
分蘖数对小麦产量有很大贡献。利用甲基磺酸乙酯诱变，我们之前发现了少蘖突变体。从分蘖早期到抽穗期，该突变体的分蘖数显著低于相应的野生型。与野生型相比，千粒重和粒长分别增加了15.41%和31.44%，而株高和穗长分别降低了26.13%和37.25%。在返青期和拔节期进行转录组分析以鉴定差异表达基因（DEG）。使用京都基因与基因组百科全书（KEGG）和基因本体论（GO）数据库进行功能富集分析，结果显示在分蘖发育过程中与ADP结合、跨膜运输和转录调控相关的基因存在差异表达。突变体分蘖数的差异导致独脚金内酯（SL）和脱落酸（ABA）途径中的基因上调。具体而言，SL生物合成基因（）、、、和（）上调了3.37至8.23倍；SL信号转导基因和分别上调了1.81倍和1.32倍；ABA生物合成基因 - - （）和上调了1.66倍和3.4倍；以及（）和（）基因上调了1.30至4.79倍。这表明突变体中分蘖数的减少是由于植物激素途径的改变。已知促进分蘖生长的基因上调，而已知抑制分蘖生长的基因下调。例如，促进分蘖发育的（）在突变体中上调了8.23倍；抑制分蘖发育的（）下调了1.74倍。（）或（）的表达水平没有显著差异，表明突变体中分蘖数的减少不受已知基因控制。我们的研究结果为后续小麦分蘖的遗传基础和调控机制研究提供了有价值的数据。
在线版本包含可在10.1007/s11032-024-01450-3获取的补充材料。
