Background

Chloroplasts are essential for photosynthesis and play key roles in plant development. High temperature affects structure of chloroplasts and metabolism in plants. The seryl-tRNA synthetase plays an important role in translation of proteins. Although seryl-tRNA synthetase has been widely studied in microbes and animals, few studies have reported about its role in chloroplast development under high temperature in rice.

Results

In this study, we isolated a novel temperature-sensitive chlorophyll-deficient 11 (tscd11) mutant by ethyl methane sulfonate (EMS) mutagenesis of japonica variety Wuyujing7. The tscd11 mutant developed albino leaves at the 3-leaf stage under high temperature (35 °C), but had normal green leaves under low temperature (25 °C). Consistent with the albino phenotype, impaired chloroplasts, decreased chlorophyll content and increased ROS accumulation were found in the tscd11 mutant at 35 °C. Fine mapping and DNA sequencing of tscd11 revealed a missense mutation (G to A) in the eighth exon of LOC_Os11g39670 resulted in amino acid change (Glu₃₇₄ to Lys₃₇₄). The TSCD11 gene encodes a seryl-tRNA synthetase localized to chloroplast. Complementation test confirmed that the point mutation in TSCD11 is responsible for the phenotype of tscd11. TSCD11 is highly expressed in leaves. Compared with the wild type (WT), mutation in TSCD11 led to significant alteration in expression levels of genes associated with chlorophyll biosynthesis, photosynthesis and chloroplast development under high temperature.

Conclusions

TSCD11, encoding a seryl-tRNA synthetase localized to chloroplast, is vital to early chloroplast development at high temperature in rice, which help to further study on the molecular mechanism of chloroplast development under high temperature.

中文翻译：

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水稻高温下叶绿体早期发育的TSCD11基因的分离。

背景

叶绿体对于光合作用至关重要，并在植物发育中起关键作用。高温会影响植物的叶绿体结构和新陈代谢。丝氨酰-tRNA合成酶在蛋白质翻译中起重要作用。尽管已经在微生物和动物中对丝氨酰-tRNA合成酶进行了广泛研究，但很少有报道报道其在水稻高温下叶绿体发育中的作用。

结果

在这项研究中，我们分离了一种新的温度-敏感的叶绿素-缺陷11（tscd11）通过的甲磺酸乙酯（EMS）诱变突变粳稻品种Wuyujing7。所述tscd11突变体在高温（35℃）下的3叶期开发的白化叶，但低温（25℃）下具有正常的绿叶。与白化病表型一致，叶绿体受损，叶绿素含量降低，并且在tscd11突变体中在35°C时增加了ROS积累。精细定位和进行DNA测序tscd11揭示的第八外显子的错义突变（G到A）LOC_Os11g39670导致氨基酸改变（Glu ₃₇₄至Lys ₃₇₄）。该TSCD11基因编码丝氨酰-tRNA合成酶定位于叶绿体。补充测试证实TSCD11中的点突变是tscd11表型的原因。TSCD11在叶中高表达。与野生型（WT）相比，TSCD11的突变导致高温下叶绿素生物合成，光合作用和叶绿体发育相关基因的表达水平发生显着变化。

结论

TSCD11是一种编码位于叶绿体中的丝氨酰-tRNA合成酶，对水稻高温下早期叶绿体的发育至关重要，这有助于进一步研究高温下叶绿体发育的分子机制。