【作者】 李伟；

【导师】 宋喜悦；

【作者基本信息】 西北农林科技大学 ， 作物学， 2020， 硕士

【摘要】 小麦是重要的粮食作物,随着世界人口不断增长和耕地面积日益缩减,保障未来小麦需求安全势在必行。利用杂种优势是提高小麦产量的最有效途径之一,而小麦细胞质雄性不育（Cytoplasmic male sterility,CMS）是利用该途径的重要手段。然而,在小麦上,能够真正利用到大田生产的CMS系缺乏,因此发掘新的小麦雄性不育系对加快小麦杂种优势利用具有重要意义。U706A是本课题组经过多年培育形成的一种CMS系,其细胞质来源是单芒山羊草（Aegilops uniaristata）。本研究以U706A、其同核保持系706B以及56个来源广泛的恢复系为材料,通过对其表型进行观察以确定其不育性以及败育特点;利用转录组测序的方法来鉴定与其不育相关的差异基因和代谢通路,探究其败育机制;通过将不育系与恢复系杂交,检测其易恢性和稳定性;通过用保持系、恢复系和不育系构建一个BC₁F₁群体,调查该群体的育性分布进行遗传分析并定位该基因,通过以上几方面的研究,旨在综合评价该不育系在杂交小麦育种中的利用潜力,为育种家利用该不育系提供参考,为加快小麦杂种优势利用奠定基础。获得的主要结果如下:1.通过对不育系U706A、保持系706B花药和花粉粒的扫描电镜观察、花粉粒的I₂-KI染色以及DAPI染色观察发现,706B的花药饱满,顶端开裂,外壁纹路整齐,内壁乌氏体排列紧密,花粉粒饱满且染色充分。与706B相比,U706A的花药瘦小且干瘪,花药顶端不开裂,外壁纹路紊乱,内壁乌氏体稀疏,花粉粒畸形且染色不充分,表现为染败。2.对处于二核期的U706A和706B的花药进行RNA-Seq,获得9,799个差异表达基因,其中上调5,928个,下调3,871个。然后对这些差异表达基因通过数据库比对进行功能注释,综合GO和KEGG分析结果,推测磷脂酰肌醇代谢通路和果胶代谢通路可能与育性相关;另外,对转录因子相关的转录本分析,推测转录因子MYB21可能影响U706A的育性。3.通过两年两地U706A与恢复系的F₁代自交结实率的测定,并以K706A与恢复系的F₁代为对照。结果发现,U706A的恢保关系与K706A基本一致,U706A的整体结实率略低,但亦有高恢复材料,结实率可达90%以上;对比三个环境下的数据可以发现,U706A后代的稳定性要好于K706A。4.通过U706A//706B/LK783构建BC₁F₁群体,单株套袋进行遗传分析,结果发现不育株:可育株≈1:3,符合两对主效基因控制性状的期望,然后经过标记筛选与带型统计将其中一个恢复基因定位在1B染色体上的标记AX-109965610和gwm18之间,两个标记分别与恢复基因的遗传距离为2.5cM和19.6cM。更多还原

【Abstract】 Wheat is an important crop in the world.As the population continues to increase and the area of cultivated land is shrinking,it is important to ensure the wheat supply.Using heterosis is one of the most effective ways to increase wheat yield,and wheat cytoplasmic male sterility（CMS）is an important tool to use this approach.By using CMS,the process of heterosis utilization can be greatly accelerated.However,in wheat,The CMS that can really be used in field is lacking,so the discovery of new wheat CMS lines is of great significance to accelerate the utilization of wheat heterosis.U706A is a CMS line that our research group has cultivated for many years.Its cytoplasmic source is Aegilops uniaristata.In this study,U706A,its maintainer line 706B,and 56 restore lines from a wide range of sources were used as materials.Observation of their phenotypes to determine sterility and abortion characteristics;transcriptome sequencing was used to identify the sterility related differential genes and metabolic pathways to explore the mechanism of abortion;by crossing sterile lines and restorer lines to detect the restorability and stability;by constructing a BC₁F₁population,investigate the fertility distribution of the population for genetic analysis and mapping the testore gene,through the above research,aims to comprehensively evaluate the utilization potential of U706A in hybrid wheat breeding,provide a reference for breeders to use the sterile line,and lay the foundation for accelerating the utilization of wheat heterosis.The main results obtained are as follows:1.Scanning electron microscope observation,I₂-KI staining and DAPI staining of anthers and pollen grains of sterile line U706A and maintainer line 706B revealed that the anthers of 706B were full,the top was cracked,the parallel swelling lines of epidermal cells in the outer walls of the anthers were clear and arranged neatly in 706B,the microspores were plump and spherical,and the Ubisch bodies on the inner walls were dense.By contrast,the parallel swelling lines of epidermal cells were not arranged neatly in U706A,the microspores were deformed,and the Ubisch bodies were sparse.The microspores of 706B were stained uniformly and deeply by KI-I₂,but those of U706A were stained weakly and some microspores were not stained.2.9,799 differentially expressed genes were obtained by RNA-Seq of U706A and 706B anthers in binuclear stage,of which 5,928 were up-regulated and 3,871 were down regulated.Then,we annotated these differentially expressed genes through database comparison.Based on the results of GO and KEGG analysis,we speculated that phosphatidylinositol metabolism pathway and pectin metabolism pathway might be related to fertility.In addition,we analyzed transcription factors related transcripts and speculated that the transcription factor MYB21 might affect the fertility of U706A.3.The self seeding rate of F₁ generation of U706A and restorer line in two years was determined,and the F₁ generation of K706A and restorer line was used as control.The results showed that the relationship between the restoration and the conservation of U706A was basically the same as that of K706A.The overall seed setting rate of U706A was slightly lower,but there were also great restorer lines,the seed setting rate could reach more than90%.Comparing the data of three environments,it can be found that the stability of the offspring of U706A was better than that of K706A.4.BC₁F₁population was constructed by U706A//706B/LK783,and genetic analysis showed that sterile plant:fertile plant≈1:3,which met the expectations of two pairs of gene control characters.Then one of the restorer genes was located between the markers AX-109965610 and gwm18 on chromosome 1B through marker screening and band type statistics.The genetic distance between the two markers and the restorer gene was 2.5cM and 19.6cM respectively.更多还原