Li Zhi, Ren Tianheng, Yan Benju, Tan Feiquan, Yang Manyu, Ren Zhenglong
Agronomy College, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China.
PLoS One. 2016 Jan 14;11(1):e0146943. doi: 10.1371/journal.pone.0146943. eCollection 2016.
The chromosome arm 1RS of rye (Secale cereal L.) has been used worldwide as a source of genes for agronomic and resistant improvement. However, the 1RS arm in wheat has end-use quality defects that are partially attributable to the presence of ω-secalins, which are encoded by genes at the Sec-1 locus. Various attempts in removing the Sec-1 genes from the 1RS.1BL translocation chromosome have been made. In the present study, two new primary 1RS.1BL translocation lines, T917-26 and T917-15, were developed from a cross between wheat variety "A42912" and Chinese local rye "Weining." The lines T917-15 and T917-26 carried a pair of intact and homogeneous 1RS.1BL chromosomes. The line T917-26 also harbored an expression deletion of some genes at the Sec-1 locus, which originated from a mutation that occurred simultaneously with wheat-rye chromosome translocations. These results suggest that the accompanying mutations of the evolutionarily significant translocations are remarkable resources for plant improvement. Comparison of translocation lines with its wheat parent showed improvements in the end-use quality parameters, which included protein content (PC), water absorption (WA), sodium dodecyl sulfate sedimentation (SDSS), wet gluten (WG), dry gluten (DG) and dough stickiness (DS), whereas significant reduction in gluten index (GI) and stability time (ST) were observed. These findings indicate that 1RS in wheat has produced a higher amount of protein, although these comprised worse compositions. However, in the T917-26 line that harbored an expression deletion mutation in the Sec-1 genes, the quality parameters were markedly improved relative to its sister line, T917-15, especially for GI and DS (P < 0.05). These results indicated that expression deletion of Sec-1 genes significantly improves the end-use quality of wheat cultivars harboring the 1RS.1BL translocation. Strategies to remove the Sec-1 genes from the 1RS.1BL translocation in wheat improvement are discussed.
黑麦（Secale cereal L.）的染色体臂1RS已在全球范围内用作农艺性状改良和抗性改良的基因来源。然而，小麦中的1RS臂存在最终用途品质缺陷，部分原因是存在ω-黑麦碱，其由Sec-1位点的基因编码。人们已尝试多种方法从1RS.1BL易位染色体上去除Sec-1基因。在本研究中，从小麦品种“A42912”与中国地方黑麦“Weining”的杂交后代中培育出两个新的初级1RS.1BL易位系T917-26和T917-15。T917-15和T917-26系携带一对完整且同源的1RS.1BL染色体。T917-26系还存在Sec-1位点一些基因的表达缺失，这源于与小麦-黑麦染色体易位同时发生的突变。这些结果表明，具有进化意义的易位伴随的突变是植物改良的重要资源。将易位系与其小麦亲本进行比较，发现最终用途品质参数有所改善，包括蛋白质含量（PC）、吸水率（WA）、十二烷基硫酸钠沉淀值（SDSS）、湿面筋（WG）、干面筋（DG）和面团粘性（DS），而面筋指数（GI）和稳定时间（ST）显著降低。这些发现表明，小麦中的1RS产生了较高含量的蛋白质，尽管其组成较差。然而，在Sec-1基因存在表达缺失突变的T917-26系中，相对于其姊妹系T917-15，品质参数有显著改善，尤其是GI和DS（P < 0.05）。这些结果表明，Sec-1基因的表达缺失显著改善了携带1RS.1BL易位的小麦品种的最终用途品质。本文还讨论了在小麦改良中从1RS.1BL易位上去除Sec-1基因的策略。
