马家柚线粒体基因组序列特征、密码子偏好性及系统发育分析OA

[Objective]The study aims to investigate the structural characteristics and phylogenetic re-lationships of the mitochondrial genome in Citrus maxima(L.)Osbeck cv.'Majiayou'.[Method]The mitochondrial genome of C.maxima(L.)Osbeck cv.'Majiayou'was sequenced using high-throughput sequencing.Bioinformatics software was employed to assemble,annotate,map,and analyze sequence cha-racteristics of the mitochondrial genome.A phylogenetic tree of five Citrus species was constructed based on this mitochondrial genome sequence.[Result]The mitochondrial genome size of C.maxima(L.)Os-beck cv.'Majiayou'was 516 383 bp,with a complete monocyclic structure and a GC content of 45.15%.Annotation identified 65 genes,including 35 protein coding genes,27 tRNA genes,and 3 rRNA genes.A to-tal of 64 SSRs(A/T single nucleotide repeats dominant)and 100 Longrepeat sequences(51 direct repeats and 49 palindromic repeats)were identified in the mitochondrial genome of C.maxima(L.)Osbeck cv.'Majiayou'.This mitogenome exhibited weak codon usage bias with a preference for A and U endings.The codon usage preference of C.maxima(L.)Osbeck cv.'Majiayou'mitochondrial genome was influenced by both internal mutations and natural selection,with the latter being dominant.Twenty-two optimal co-dons were determined(AAU,GAU,UGU,CAA,AAA,UUU,UAU,AUU,AUG,UAA,GGA,GGU,CCA,CCU,ACU,GUA,GUU,CGA,CGU,UUA,UCA,and UCU),all ending in A and U.The mitochon-drial genome of C.maxima(L.)Osbeck cv.'Majiayou'showed high collinearity with the mitochondrial genome of Citrus sinensis,indicating a close genetic relationship between the two.There were 21 chloro-plast gene fragments of C.maxima(L.)Osbeck cv.'Majiayou'transferred to its mitochondrial genome,with a total length of 12 195 bp.[Conclusion]Sequence characteristics and codon usage bias of mitochon-drial genome of Citrus maxima(L.)Osbeck cv.'Majiayou'were elucidated,with the closest genetic rela-tionship to Citrus sinensis among the studied Citrus species being demonstrated.