Abstract:

In order to explore new approaches for high-oil peanut breeding and establish a new method for directly developing high-oil peanut germplasm,this study employed in vitro mutagenesis breeding technology to create new high-oil peanut germplasm.Jihua 9 embryo leaflet was used as mutagenic test materials,Jihua 9 and Jihua 54 were used as control test materials,and bleomycin was used as mutagenic agent.The ovules were sterilized and placed in gradient mutagenesis medium and screened for semi-lethal concentrations of bleomycin.After somatic embryos germinated into seedlings,sterile peanut seedlings were used as rootstocks,and transplanted to the field.Bioinformatics analysis of two known regulated peanut fat synthesis genes WRI1 and experimental feasibility validation by the correlation of WRI1 gene expression in grain and crude fat content of mutagenic plants were conducted.The results were best when the bleomycin was 3 mg/L.The crude fat content of IM13-3 was higher than that of Jihua 9(CK₁,test variety control)and Jihua 54(CK₂,high oil variety control).Two WRI1 genes,WRI1X2 and WRI1X1,encoding 366 and 357 amino acids,respectively,were both unstable hydrophilic proteins. WRI1 gene expression and crude fat content were significantly positively associated in grain.Bleomycin was first used as a peanut vitro mutagenesis agent,and IM13-3 was obtained with a crude fat content of 56.64%.It further proves the authenticity of Jihua 9 high oil mutant and the feasibility of peanut in vitro mutagenesis method. The gene expression level of the high-oil mutant WRI1 was determined and was significantly different from the control varieties. Demonstrate the feasibility of breeding methods for in vitro mutagenesis of peanut.

Key words: High-oil peanut, Mutagenesis in vitro, Bleomycin, WRI1, Expression analysis