Sequencing And Analysis Of Cytoplasmic Male Sterile Line P30A And Maintainer P30B Mitochondrial Genome(Gossypium Hirsutum L.))

Cotton is a plant of significant economic importance worldwide. The male sterility on cotton has played an important role in heterosis usage in cotton. Utilization of the male sterile system have made a breakthrough in conquering breeding bottleneck by artificial emasculation and unfolded a bright outlook for promoting commercial production of hybrid seed.In this study, mtochondria were obtained from 7-days-old etiolated seedlings of a variety of upland cotton (Gossypium hirsutum L.),’P30B’ and ’P30A’. Purified mitochondria were obtained by Sucrose differential centrifugation and discontinuous sucrose density gradient centrifugation. The mitochondrial DNA was extracted by gel lysis. Upland cotton mtDNA were sequenced using PacBio and Solexa. Finally, the upland cotton P30B and P30A mt genome was assembled into a single, circular molecule, with the length 621,692 bp and 627,590bp.68 genes were annotated in the P30B and P30A mt genome, including 35 protein-coding genes, four rRNA genes and 29 tRNA genes. Among the eight multi-copy genes (i.e., nadl, rps3, rrn26, trnW, trnS (GCT), trnP, trnfM and trnM), nadl gene contains an additional copy, and rps3 gene has an extra pseudogene-like copy. The protein coding sequences are 26942bp, accounting for 4.33% 和 4.29%.And the repeat sequences are 118565bp 和 12155Obp separately,accounting for 19.1% 和 19.4%. According to the results, we found the gene number, gene type and gene order are same between P30B and P30A.Meanwhile,18 candidate genes were considered as cytoplamic male sterile genes by comparision of P30B and P30A mitochondrial gennome.