The barley plastome mutant CL2 affects expression of nuclear and chloroplast housekeeping genes in a cell-age dependent manner
The barley plastome mutant CL2 affects expression of nuclear and chloroplast housekeeping genes in a cell-age dependent manner
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DOI：
10.1007/s00438-008-0321-x
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发表时间：
2008-04-01
影响因子：
3.1
通讯作者：
Boerner, Thomas
中科院分区：
文献类型：
--
作者：
Colombo, Noemi;Emanuel, Carola;Boerner, Thomas
大麦质体突变体CL2（细胞质系2）在infA基因中携带点突变，infA基因是保守的翻译起始因子I（IF）的细菌基因的同源物。infA在质体中的功能尚不清楚。在CL2的突变导致一个时间叶绿素缺乏症的初级叶片是正常的，在进一步发展过程中的基部和中部。我们比较了CL 2和野生型初生叶不同部分中选定的核基因和质体基因的表达，没有发现突变对质体转录产生不利影响的迹象。我们观察到RpoTp（编码噬菌体型核编码的质体RNA聚合酶）的表达增强，这表明是由逆行质体信号传导引起的。基部和顶部的质体rRNA数量减少与infA突变导致质体翻译的时间和位置依赖性缺陷导致质体发育延迟的想法一致。CL2叶中段表型的正常化与叶绿体16S rRNA和RbcL的野生型水平以及质体管家基因的表达增加相关。在CL2叶尖的细胞中没有观察到正常化，这表明与其他叶部分相比，在初级大麦叶尖的细胞中调节叶绿体发育的方式不同。
The barley plastome mutant CL2 (cytoplasmic line 2) carries a point mutation in the infA gene, a homologue of the bacterial gene for the conserved translation initiator factor I (IF]). The function of infA in plastids is not known. The mutation in CL2 leads to a temporal chlorophyll deficiency in the primary leaf blade that is normalised in the basal and middle parts during further development. We have compared the expression of selected nuclear and plastid genes in different parts of primary leaves of CL2 and wild-type and found no indication for an adverse effect of the mutation on plastidial transcription. We observed an enhanced expression of RpoTp) (encoding the phage-type nuclear-encoded plastid RNA polymerase) suggested to be caused by retrograde plastid signalling. Decreased amounts of plastid rRNA in basal and top sections are in agreement with the idea that the mutation in infA leads to a time- and position-dependent defect of plastid translation that causes a delay in plastid development. The normalisation of the phenotype in the middle section of CL2 leaves correlates with wild-type levels of chloroplast 16S rRNA and RbcL and increased expression of plastid housekeeping genes. The normalisation was not observed in cells at the tip of CL2 leaves suggesting different ways of regulating chloroplast development in cells at the tip of primary barley leaves as compared with other leaf sections.