玉米C型不育系、保持系和恢复系线粒体基因组的比较分析

以不育系K932S和K169S、保持系K169和恢复系K932R为供试材料,通过二代测序技术对线粒体基因组序列进行比较分析,挖掘玉米CMS-C败育相关基因(ORFs)。结果表明,不育胞质K932S、K169S和K932R线粒体基因组大小分别为739 676、739 723、739 765 bp,正常胞质K169为569 617 bp。注释到蛋白编码基因33个,tRNA基因15～16个和rRNA基因3～4个。大于100 bp重复序列在不育胞质和正常胞质基因组中分别为19、10个,小于100 bp重复序列差异不大。同源片段在3个不育胞质基因组中排列顺序一致,共线性达99%以上。正常胞质中3个片段反转,排列顺序也发生了重大改变,相似度为95%。4个基因组中发现ORFs基因145～151个,其中,K169S与K169间差异基因(ORFs)高达13个,与K932S或K932R间差异仅1个,K169S特有ORFs基因8个。筛选出orf429(atp6-c)、orf104-s、orf410、orf349和orf246共5个ORFs,可能与CMS-C败育相关。

Comparative Analyses of Mitochondrial Genomes of C-type Sterile Line, Maintainer Line and Restorer Line in Maize

In order to dig up genes(ORFs) related to CMS-C sterility in maize, the sequences of the mitochondrial genome of four materials, sterile line K932S and K169S, maintainer line K169 and restorer line K932R, were comparatively analyzed by using next-generation sequencing technology. The results showed that the mitochondrial genome length of sterile cytoplasm K932S, K169S and K932R were 739 676 bp, 739 723 bp and 739 765 bp, respectively; and that of normal cytoplasm K169 was 569 617 bp; 33 protein coding genes, 15-16 tRNA genes and 3-4 rRNA genes were annotated. There were 19 and 10 repetitive sequences longer than 100 bp in the sterile cytoplasmic and normal cytoplasmic genomes, respectively, and repetitive sequences shorter than 100 bp presented little differences; Among the three sterile cytoplasmic genomes, the homologous fragments are arranged in the same order, with a collinearity of 99%, however, three reversed fragments were found in the normal cytoplasm, and the arrangement order also changed, with a similarity of 95%. Among the four genomes, 145-151 ORFs were found, there were 13 differential genes(ORFs) between K169S and K169, but only 1 of that was extracted between K932S and K932R, 8 unique ORFs was discovered in K169S mitochondrial genome. Five ORFs including orf429(atp6-c), orf104-s, orf410, orf349 and orf246 were screened, which may be related to CMS-C abortion. Those results may provide some genomic information for dissecting the mechanism of CMS-C abortion in maize.