Mapping And Screening Of Candidate Genes For Regulation Of Sterility Of 1205AB In Brassica Napus

Rapeseed is an important oil crop,which can be used as edible oil,feed,vegetables,fertilizer,honey,sightseeing,biodiesel,lubricating oil,and industrial materials and so on.Heterosis utilization is an effective way to improve the yield,quality and resistance of rapeseed,while male sterility is the main way of heterosis utilization in Brassica napus.The recessive nuclear male sterility of the rapeseed has the advantages of complete and stable sterility,rich cytoplasm resource,widely recovery source and so on,so it has become an important way of heterosis utilization in China.In this study,genetic analysis,cytological analysis,transcriptome sequencing,BSA sequencing and QTL Mapping were used to study the mechanism of the sterility in 1205AB.The main results of this study were shown as follows:?1?Genetic analysis of fertility showed that the fertility segregation ratio in siblings and F₂is 1:1 and 3:1respectively,indicating that the recessive sterility of 1205AB was controlled by a pair of alleles.?2?Paraffin section analysis indicated that pollen mother cells of fertile anthers and sterile anthers can normally form tetrads,then stertile microspores can be degraded in comparision with the normal development of fertile anthers.Therefore,the critical period of 1205A abortion is the microspore period,microspores in sterile flower degradation cann't form normal pollen grains.?3?A total of 1059 ILP markers were chosen for screening the fertile and sterile bulks,and finally 10 ILP markers closely linked to the sterility were obtained.The q Bn.1205ms1 gene for sterility was located between At2g44050 and At1g26180 on the C03,and the distance between the markers to QTL peak was 14.0c M and 24.1c M respectively.?4?By RNA-seq method,46117758 and 44984428 clean reads of fertile and sterile buds were gotten and a total of 2499 DEGs including 134 up-regulated genes and 2315 down-regulated genes were gotten;finally 117 fertility-related DEGs including 48 up-regulated and 69down-regulated ones were obtained by GO and KEGG methods.?5?Using BSA technique,the sterile genes were mapped in one 3.5Mb region of C03 chromosome,where 9 candidate genes could be involved in sterility from 416 genes.?6?By joint analysis of genetic analysis,cytological analysis,transcriptome sequencing,BSA sequencing,QTL mapping and q RT-PCR results,we screened two candidate genes of LOC106438923?AT3G02230,RGP1?and LOC106388682?AT3G01700,AGP11?.RGP1 and RGP1 have a male gametophyte-lethal function,and the function-loss of AGP11 could lead to low fertility.By joint analysis of multiple ways,we finally obtained 2 candidate genes for genetic regulation of sterility in 1205AB.The research will lay the foundation for the study of the sterility mechanism of 1205AB,the cloning of sterile genes,the utilization of heterosis and molecular marker-assisted breeding.