Organellar gene transcription and early seedling development are affected in the rpoT;2 mutant of Arabidopsis
Organellar gene transcription and early seedling development are affected in the rpoT;2 mutant of Arabidopsis
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DOI：
10.1111/j.1365-313x.2004.02022.x
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发表时间：
2004-04-01
期刊：
影响因子：
7.2
通讯作者：
Bhalerao, RP
中科院分区：
文献类型：
--
作者：
Baba, K;Schmidt, J;Bhalerao, RP
从一组激活标记的T-DNA插入系中分离到一个表现出根长度缩短的拟南芥突变体，该插入系是在一个异常根生长的筛选中获得的。该突变体还表现出下胚轴长度缩短、绿色化延迟和叶形改变。对突变体的分子遗传分析表明，在编码噬菌体类型RNA聚合酶(RNAP)的同源物的基因RpoT；2中插入了单一的T-DNA，该基因同时针对线粒体和叶绿体。第二个T-DNA标记的等位基因也表现出类似的表型。RpoT；2的突变影响了光诱导的几种质体mRNAs和蛋白质的积累，导致光合作用效率降低。与叶绿体基因表达的变化相反，rpoT；2突变对所检测的线粒体基因转录本和蛋白质的积累没有重大影响。RpoT；2突变体在另外两个细胞器导向的核编码的RNAP的转录水平上表现出组织特异性的变化，RpoT；1和RpoT；3。这表明这三个RNAP通过细胞器到细胞核的通讯在调节通路之间存在串扰。这些数据为RpoT；2在叶绿体基因表达和植物早期发育中的作用提供了重要的信息。
An Arabidopsis mutant that exhibited reduced root length was isolated from a population of activation-tagged T-DNA insertion lines in a screen for aberrant root growth. This mutant also exhibited reduced hypocotyl length as well as a delay in greening and altered leaf shape. Molecular genetic analysis of the mutant indicated a single T-DNA insertion in the gene RpoT;2 encoding a homolog of the phage-type RNA polymerase (RNAP), that is targeted to both mitochondria and plastids. A second T-DNA-tagged allele also showed a similar phenotype. The mutation in RpoT;2 affected the light-induced accumulation of several plastid mRNAs and proteins and resulted in a lower photosynthetic efficiency. In contrast to the alterations in the plastid gene expression, no major effect of the rpoT;2 mutation on the accumulation of examined mitochondrial gene transcripts and proteins was observed. The rpoT;2 mutant exhibited tissue-specific alterations in the transcript levels of two other organelle-directed nuclear-encoded RNAPs, RpoT;1 and RpoT;3. This suggests the existence of cross-talk between the regulatory pathways of the three RNAPs through organelle to nucleus communication. These data provide an important information on a role of RpoT;2 in plastid gene expression and early plant development.