Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-Saving, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050022, China.
College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
Int J Mol Sci. 2021 Apr 3;22(7):3748. doi: 10.3390/ijms22073748.
Tillering is a crucial agronomic trait of wheat; it determines yield and plant architecture. Strigolactones (SLs) have been reported to inhibit plant branching. D14, a receptor of SLs, has been described to affect tillering in rice, yet it has seldomly been studied in wheat. In this study, three homoeologous genes, , , and , were identified. , , and were constitutively expressed, and had a higher expression level in most tissues. TaD14 proteins were localized in both cytoplasm and nucleus. An SNP and a 22 bp insertion/deletion (Indel) at the exon regions of were detected, forming three haplotypes, namely , , and . Due to the frameshift mutation in the coding region of , the interaction of 4D-HapII with TaMAX2 and TaD53 was blocked, which led to the blocking of SL signal transduction. Based on the two variation sites, two molecular markers, namely and , were developed. Association analysis suggested that haplotypes of were associated with effective tillering number (ETN) and thousand kernel weight (TKW) simultaneously in four environments. The favorable haplotype underwent positive selection in global wheat breeding. This study provides insights into understanding the function of natural variations of and develops two useful molecular markers for wheat breeding.
分蘖是小麦的一个重要农艺性状，它决定了产量和植株结构。独脚金内酯（SLs）已被报道能抑制植物分枝。D14 是 SLs 的受体，已被描述影响水稻分蘖，但在小麦中很少研究。本研究鉴定了三个同源基因 、 、和 。 、 和 组成型表达，而 在大多数组织中表达水平更高。TaD14 蛋白定位于细胞质和细胞核。在 的外显子区域检测到一个 SNP 和一个 22bp 的插入/缺失（Indel），形成三个单倍型，分别为 、 、和 。由于 在编码区的移码突变，4D-HapII 与 TaMAX2 和 TaD53 的相互作用被阻断，导致 SL 信号转导受阻。基于这两个变异位点，开发了两个分子标记，即 和 。关联分析表明，在四个环境中， 的单倍型与有效分蘖数（ETN）和千粒重（TKW）同时相关。有利的单倍型 经历了全球小麦育种中的正选择。本研究为理解 自然变异的功能提供了新的认识，并开发了两个用于小麦育种的有用的分子标记。
