Cytoplasmic Male Sterility Caused By Mitochondrial ATPase In Tobacco

The cytoplasmic male sterility?CMS?affects the breeding of male sterile lines,the interaction of nuclear quality,the mitochondrial semiautonomous genetic system and the heterosis of crop.CMS is the result of interaction between cytoplasmic genes and nuclear genes,and its related effects in crops have attracted much attention.Tobacco is an important model crop,and mitochondrion is an important functional cell organ in crops.Therefore,the research on mitochondrial ATP enzyme complex is extremely important for crop breeding.To investigate the relationship between ATPase and CMS in,three pairs of maintainers and CMS lines tobacco with the same nuclear background were selected as materials,and the DNA & RNA sequence differences,editing site differences,protein structure differences and protein-protein interaction?PPI?differences between 5 subunits?orfB,orf25,atp9,atp1 and atp6?in the mitochondrial ATP synthase were analyzed in this study.Furthermore,the PPI of the key genes from ATPase in the male sterile line and its maintainer line were tested by yeast two-hybrid test to discuss the correlation between the PPI and CMS.In addition,RNA editing is closely related to tobacco CMS,but the currently published RNA editing sites from tobacco are very limited.Based on the high-dimensional descriptor selection nonlinearly?HDSN?and the support vector classification?SVC?,we further used the mitochondrial RNA editing site information from the relatively perfect model plant Arabidopsis thaliana,Brassica napus and Oryza sativa,combined with the ones from our sequencing tobacco to construct the nonlinear high-precision prediction model for tobacco RNA editing sites,and this work will provide help for exploring the related biological phenomena about editing.The results showed that: 1)the sequence of 5 target genes in the sterile line had 1 to 12 different base mutations,and resulted in 1 to 10 amino acid changes,respectively;2)the RNA editing mode was C to U,and the atp6 gene had been found 6 editing sites in the sterile line and resulted in 6 encoding amino acid changes;3)the basic amino acid changes caused the differences in the primary structure,the secondary structure,the super secondary structure and tertiary structure,among which the difference of ATP6 was the most significant;4)the PPI prediction analysis suggested that ATP9 interacted with ATP6 in the ATP enzyme,and the yeast two-hybrid test experimently disguished that the PPI of the two proteins in CMS line was more obvious than the one in maintainer line;5)two high precision prediction models?Ina₉5 and Ina₉6?with the independent test accuracy of 0.91 and 0.87 were constructed for tobacco mitochondrial RNA editing sites,and our results were better than the reference models.To sum up,the multiple analysis of sequence,structure and PPI supported atp6 as the key gene in mitochondrial ATPase and most likely to be related to fertility,and our mitochondrial RNA editing site prediction models had excellent performance in the editing site prediction of tobacco ATPase.All these works will be the important foundation for the later research from ATPase to the mitochondrial omics,and will provide stronger support for further analysis of crop CMS.