Loss of the plastid envelope protein AtLrgB causes spontaneous chlorotic cell death in Arabidopsis thaliana.
Loss of the plastid envelope protein AtLrgB causes spontaneous chlorotic cell death in Arabidopsis thaliana.
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DOI：
10.1093/pcp/pcr180
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发表时间：
2012
影响因子：
4.9
通讯作者：
Mizuki Yamaguchi;K. Takechi;F. Myouga;Shinya Imura;Hiroshi Sato;S. Takio;K. Shinozaki;H. Takano
中科院分区：
文献类型：
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作者：
Mizuki Yamaguchi;K. Takechi;F. Myouga;Shinya Imura;Hiroshi Sato;S. Takio;K. Shinozaki;H. Takano
为了鉴定与质体功能有关的核基因，我们使用激活/解离（Ac/Ds）转座子标记系统分析了具有白化病、淡绿色或杂色叶的拟南芥突变体。在这项研究中，我们专注于突变体与Ds插入基因At 1g 32080（AtLrgB），它编码的同源物的细菌膜蛋白LrgB。尽管细菌LrgB的详细功能仍不清楚，但据推测，LrgB与LrgA合作对抗细胞死亡和裂解。RT-PCR和启动子-GUS分析表明，AtLrgB在叶、茎和花中表达，但在根中不表达。此外，它在叶片中的表达一直持续到衰老。我们使用了三个Ac/Ds标记的突变体（atlrgB），表现出相同的表型。在短日照条件下对幼苗的连续观察中，我们发现突变体植株在发育早期的子叶和真叶表现出与野生型植株相似的立即变绿，之后某些部分表现出褪绿表型。相反，植物发育后期的真叶没有退化。当atlrgB突变体在连续光照下生长时，其褪绿表型被抑制。用正常AtLrgB转化恢复了这些表型。台盼蓝染色和电镜观察表明，褪绿细胞死亡发生在白色部门。atlrgB的表型类似于病变模拟突变体中的表型，表明AtLrgB对细胞死亡的功能，类似于细菌Lrg系统。
To identify nuclear genes involved in plastid function, we analyzed Arabidopsis thaliana mutants with albino, pale green or variegated leaves using the Activator/Dissociation (Ac/Ds) transposon tagging system. In this study, we focused on mutants with a Ds insertion in the gene At1g32080 (AtLrgB), which encodes a homolog of the bacterial membrane protein LrgB. Although the detailed function of bacterial LrgB remains unclear, it is speculated that LrgB functions against cell death and lysis in cooperation with LrgA. Reverse transcription-PCR (RT-PCR) and promoter-GUS (β-glucuronidase) analyses showed that AtLrgB is expressed in leaves, stems and flowers, but not in roots. Moreover, its expression in leaves continued until senescence. We used three Ac/Ds-tagged mutants (atlrgB) that showed the same phenotypes. During the continuous observation of seedlings under short-day conditions, we found that the cotyledons and true leaves of the mutant plants during early development showed immediate greening, similar to wild-type plants, after which some parts showed a chlorotic phenotype. In contrast, true leaves at the late stage of plant development did not show degreening. When the atlrgB mutant was grown under continuous light, its chlorotic phenotype was suppressed. Transformation with normal AtLrgB restored these phenotypes. Trypan blue staining and electron microscopic observations indicated that chlorotic cell death occurred in the white sectors. The phenotypes of atlrgB resembled those in lesion mimic mutants, suggesting that AtLrgB functions against cell death, similar to the bacterial Lrg system.