10个线粒体基因在甘蓝型油菜NCa不育系统不同组织中的转录调控及其与育性的关系

用10个线粒体基因为探针,对NCα不育系、保持系和可育F1的苗期叶片、幼蕾及未成熟种子的线粒体RNA进行了Northern分析。结果表明,这10个线粒体基因除atp6外,其余9个基因在同一材料的不同组织中没有表达差异,都属于组成型表达的线粒体基因。其中,off139、orf222、atp1、cox1、cox2、cob、rm5S、rm26S等8个线粒体基因在不育系、保持系和可育F1的苗期叶片、幼蕾及未成熟种子中有着相同的表达,属于表达不受核基因型影响,没有组织特异性的类型：atp9基因分别在同一材料的不同组织中的转录也基本没有变化,但是在3个不同的材料间具有表达差异：可能属于表达受核基因型影响、没有组织特异性的线粒体基因。atp6基因也在3个材料的叶、蕾和种子中都产生相同大小的转录本,但是在各个材料的不同组织中存在着信号强度的差异,可能是属于表达既受核基因型影响、又有组织特异性的线粒体基因。Orf222和off139分别在不育系和可育F1幼蕾中产生相同大小和丰度的转录本,但是在保持系幼蕾中没有检测到转录本;orf222检测到的3条转录本分别为1．1kb、0．9kb、0．6kb,而off139检测到0．8kb和0．6kb两条带。atp9探针在不育系和保持系幼蕾中都检测到1条0．6kb的转录本,而在可育F1幼蕾中检测到0．6kb和1．2kb的转录本。讨论了orf222、off139、atp9基因的表达与NCα细胞质雄性不育的可能关系。     

Three loblolly pine CesA genes expressed in developing xylem are orthologous to secondary cell wall CesA genes of angiosperms

Specific plant cellulose synthases (CesA), encoded by a multigene family, are necessary for secondary wall synthesis in vascular tissues and are critical to wood production. We obtained full-length clones for the three CesAs that are highly expressed in developing xylem and examined their phylogenetic relationships and expression patterns in loblolly pine tissues. Full-length CesA clones were isolated from cDNA of developing loblolly pine (Pinus taeda) xylem and phylogenetic inferences made from plant CesA protein sequences. Expression of the three genes was examined by Northern blot analysis and semiquantitative RT-PCR. Each of three PtCesA genes is orthologous to one of the three angiosperm secondary cell wall CesAs. The PtCesAs are coexpressed in tissues of loblolly pine with tissues undergoing secondary cell wall biosynthesis showing the highest levels of expression. Phylogenetic and expression analyses suggest that functional roles for these loblolly pine CesAs are analogous to those of orthologs in angiosperm taxa. Based upon evidence from this and other studies, we suggest division of seed plant CesA genes into six major paralogous groups, each containing orthologs from various taxa. Available evidence suggests that paralogous CesA genes and their distinct functional roles evolved before the divergence of gymnosperm and angiosperm lineages.