Study On The Characteristics Of Sterility And Restoration Of Cytoplasmic Male Sterile Wheat Line U706A With Aegilops Uniaristata Cytoplasm

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.