Characterization and Fine Mapping of a Novel Rice Albino Mutant low temperature albino 1
Characterization and Fine Mapping of a Novel Rice Albino Mutant low temperature albino 1
复制标题
新型水稻白化突变体低温白化1的表征和精细定位
DOI：
10.1016/j.jgg.2012.05.001
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发表时间：
2012-08-01
影响因子：
5.9
通讯作者：
Teng, Sheng
中科院分区：
文献类型：
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作者：
Peng, Yu;Zhang, Yi;Teng, Sheng
植物白化病突变体是研究叶绿素合成和叶绿体发育以及克隆相关基因的重要遗传资源。在这里，我们报告了一个新的水稻突变体低温白化病1（lta 1），显示白化病叶片前4叶期时，生长温度低于20摄氏度，但发展正常的绿色叶片温度高于24摄氏度或类似的形态表型在黑暗中的野生型（WT）。结果表明，低温胁迫下lta1突变体的叶绿素和叶绿素前体物含量显著低于野生型。透射电镜观察发现，白化病lta 1叶片中叶绿体发育不良，缺乏堆叠整齐的基粒，基质片层较少。这些结果表明lta1突变可能延迟了低温下光诱导类囊体的组装。遗传分析表明，该白化病表型受一个隐性基因控制。通过图位分析，我们最终将Lta1基因定位于11号染色体短臂上40.3kb的区域。在该区域有8个预测的开放阅读框（ORF），其中2个在lta1基因组中缺失。对Lta1基因的进一步研究将为揭示低温胁迫下叶绿体发育的分子机制提供一个很好的途径。
Albino mutants are useful genetic resource for studying chlorophyll biosynthesis and chloroplast development and cloning genes involved in these processes in plants. Here we report a novel rice mutant low temperature albino 1 (lta1) that showed albino leaves before 4-leaf stage when grown under temperature lower than 20 degrees C, but developed normal green leaves under temperature higher than 24 degrees C or similar morphological phenotypes in dark as did the wild-type (WT). Our analysis showed that the contents of chlorophylls and chlorophyll precursors were remarkably decreased in the lta1 mutant under low temperature compared to WT. Transmission electron microscope observation revealed that chloroplasts were defectively developed in the albino lta1 leaves, which lacked of well-stacked granum and contained less stroma lamellae. These results suggested that the lta1 mutation may delay the light-induced thylakoid assembly under low temperature. Genetic analysis indicated that the albino phenotype was controlled by a single recessive locus. Through map-based approach, we finally located the Lta1 gene to a region of 40.3 kb on the short arm of chromosome 11. There are 8 predicted open reading frames (ORFs) in this region and two of them were deleted in lta1 genome compared with the WT genome. The further characterization of the Lta1 gene would provide a good approach to uncover the novel molecular mechanisms involved in chloroplast development under low temperature stress.