小麦太谷核不育基因Ms2的图位克隆

Wheat is the No. 2 cereal crop impacting food security in China. As early as the last 60s, people started to pay attention to male sterile wheat which could be used to produce hybrid wheat. In 1972, one wheat plant whose spikes had wide-open glumes and appeared to be semitransparent in the sunlight was discovered in Taigu country in Shanxi province, which was later reconginzed as the national treasure known as "Taigu genic male sterile wheat". The Taigu male sterility is controlled by the single dominant gene Ms2 on wheat chromosome 4DS, which has been used as a powerful tool in wheat recurrent selecction and has potential application for hyrid seed production in wheat. Cloning of Ms2 gene has been a long-term goal of wheat scientists in China. In the current study, we developed the BC1F1 population from the Ms2 carrier"Taigu - Lumai 15 (LM15Ms2)"and the hexaploid synthetic wheat "SN421", took the advantage of the high-density maps of Aegilops tauschii (wheat D-genome donor) and Triticeae genome data to develop PCR markers in the Ms2 region, and located the Ms2 corresponding region in current physical maps of Ae. tauschii. Our goal is to construct the Ms2 physical map in "LM15Ms2", idnetify Ms2 candidate genes, validate putative Ms2 candidates using transgenic complementation and/or gene scilencing, and characterize Ms2-regulated transcriptome using RNA-seq techniques. This study presents great value in science and production, and will be important for food security in China.

小麦是我国第二大粮食作物，小麦生产关系我国粮食安全。上世纪60年代，我国开始关注小麦雄性不育，用以挖掘杂种优势。1972年，山西太谷诞生了一株穗部蓬松、呈半透明状的小麦，后发展为国宝级种质"太谷核不育小麦"。太谷核不育受小麦 4DS 染色体上的显性基因 Ms2 控制，在轮回选择中发挥了重要作用。克隆太谷核不育基因 Ms2 是我国小麦工作者梦寐以求的夙愿。为此,我们配制了"太谷核不育-鲁麦15 （LM15Ms2）"和人工合成小麦"SN421"的 BC1F1 回交群体，借鉴小麦 D 基因组供体 - 山羊草的高密度图谱，充分挖掘麦类作物基因组数据，现已将 Ms2 对应区域锁定在山羊草的物理图谱中。目前研究的重点是构建 LM15Ms2 中 Ms2 区域的物理图谱，分离候选基因，确认候选基因的功能，并运用转录组测序（RNA-seq）揭示Ms2 基因的调控网络。本项研究具有重要的理论和应用价值。

植物雄性不育是一种重要的性状，广泛用于杂交育种。太谷核不育小麦Ms2基因，属于显性核雄性不育基因，已用于上百个小麦品种或品系的培育，加快了我国小麦育种进程。本研究利用图位克隆技术分离到Ms2基因，通过反向遗传学手段验证了该基因的功能，并采用遗传转化技术证明Ms2基因可以引起小麦、大麦和短柄草的雄性不育。MS2基因只在部分小麦亚族物种出现，显性Ms2基因在太谷反转录转座子（Taigu）的驱动下表达，其表达呈现花药特异性。MS2蛋白很可能是通过影响翻译机制而最终导致雄性不育的。Ms2基因的克隆对小麦轮回选择或杂交制种具有重要意义。