Australian-China Joint Centre for Wheat Improvement, Food Futures Institute, College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia.
Crop Research Institute, Sichuan Academy of Agricultural Sciences, 4 Shizishan Road, Chengdu, 610066, China.
Theor Appl Genet. 2022 Jul;135(7):2369-2384. doi: 10.1007/s00122-022-04118-8. Epub 2022 May 19.
Glutamine synthetase TaGSr-4B is a candidate gene for a QTL of thousand grain weight on 4B, and the gene marker is ready for wheat breeding. A QTL for thousand grain weight (TGW) in wheat was previously mapped on chromosome 4B in a DH population of Westonia × Kauz. For identifying the candidate genes of the QTL, wheat 90 K SNP array was used to saturate the existing linkage map, and four field trials plus one glasshouse experiment over five locations were conducted to refine the QTL. Three nitrogen levels were applied to two of those field trials, resulting in a TGW phenotype data set from nine environments. A robust TGW QTL cluster including 773 genes was detected in six environments with the highest LOD value of 13.4. Based on differentiate gene expression within the QTL cluster in an RNAseq data of Westonia and Kauz during grain filling, a glutamine synthesis gene (GS: TaGSr-4B) was selected as a potential candidate gene for the QTL. A SNP on the promoter region between Westonia and Kauz was used to develop a cleaved amplified polymorphic marker for TaGSr-4B gene mapping and QTL reanalysing. As results, TGW QTL appeared in seven environments, and in four out of seven environments, the TGW QTL were localized on the TaGSr-4B locus and showed significant contributions to the phenotype. Based on the marker, two allele groups of Westonia and Kauz formed showed significant differences on TGW in eight environments. In agreement with the roles of GS genes on nitrogen and carbon remobilizations, TaGSr-4B is likely the candidate gene of the TGW QTL on 4B and the TaGSr-4B gene marker is ready for wheat breeding.
谷氨酰胺合成酶 TaGSr-4B 是 4B 上千粒重 QTL 的候选基因，该基因标记已可用于小麦育种。先前在 Westonia×Kauz 的 DH 群体中已将小麦千粒重 (TGW) 的 QTL 定位在 4B 染色体上。为了鉴定该 QTL 的候选基因，使用小麦 90K SNP 阵列对现有连锁图谱进行饱和，在五个地点进行了四个田间试验和一个温室试验，以细化 QTL。在其中的两个田间试验中施加了三个氮水平，导致在九个环境中获得了 TGW 表型数据集。在六个环境中检测到包括 773 个基因的稳健 TGW QTL 簇，其最高 LOD 值为 13.4。基于在 Westonia 和 Kauz 灌浆期间的 RNAseq 数据中 QTL 簇内的差异基因表达，选择一个谷氨酰胺合成基因 (GS: TaGSr-4B) 作为该 QTL 的潜在候选基因。在 Westonia 和 Kauz 之间的启动子区域上的 SNP 用于开发 TaGSr-4B 基因映射和 QTL 重新分析的切割扩增多态性标记。结果，在七个环境中出现了 TGW QTL，在七个环境中的四个环境中，TGW QTL 位于 TaGSr-4B 基因座上，并且对表型表现出显著的贡献。基于该标记，Westonia 和 Kauz 的两个等位基因组在八个环境中在 TGW 上表现出显著差异。与 GS 基因在氮和碳再动员中的作用一致，TaGSr-4B 可能是 4B 上 TGW QTL 的候选基因，并且 TaGSr-4B 基因标记已可用于小麦育种。
