Cool temperatures interfere with D1 synthesis in tomato by causing ribosomal pausing
Cool temperatures interfere with D1 synthesis in tomato by causing ribosomal pausing
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DOI：
10.1007/s11120-007-9169-x
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发表时间：
2007-11-01
影响因子：
3.7
通讯作者：
Ort, Donald R.
中科院分区：
文献类型：
--
作者：
Grennan, Aleel K.;Ort, Donald R.
当叶子暴露在超过可用于光合作用的光线以及超过辅助光保护和修复机制的能力时，就会发生光损伤。光损伤的一个重要位点是叶绿体编码的 D1 蛋白，它是光系统 II (PSII) 反应中心的一个组成部分。即使在最佳生长辐照度下，D1 也会受到光损伤，需要快速周转以防止光损伤 PSII 反应中心的积累以及随后的光合作用抑制。然而，当在低温下暴露于高生长光照时，对寒冷敏感的番茄 (Solanum lycopersicum) 植物中 D1 周转和替代的持续过程会受到阻碍。发现 D1 周转和替换的减少并不是由于 psbA 消息的稳态水平的变化造成的。虽然核糖体向 psbA 转录本的募集、D1 翻译的起始以及多核糖体与类囊体膜的结合正常发生，但在番茄中，低温导致核糖体在 D1 肽延伸过程中暂停。暂停位置非随机位于 D1 转录本上。核糖体暂停引起的翻译干扰使得光损伤的 PSII 中心积累，导致光合作用受到抑制。
Photodamage occurs when leaves are exposed to light in excess of what can be used for photosynthesis and in excess of the capacity of ancillary photoprotective as well as repair mechanisms. An important site of photodamage is the chloroplast encoded D1 protein, a component of the photosystem II (PSII) reaction center. Even under optimal growth irradiance, D1 is photodamaged necessitating rapid turnover to prevent the accumulation of photodamaged PSII reaction centers and consequent inhibition of photosynthesis. However, this on-going process of D1 turnover and replacement was impeded in the chilling-sensitive tomato (Solanum lycopersicum) plants when exposed to high-growth light at cool temperature. The decrease in D1 turnover and replacement was found not to be due to changes in the steady-state level of the psbA message. While the recruitment of ribosomes to psbA transcript, initiation of D1 translation, and the association of polysomes with the thylakoid membrane occurred normally, chilling temperatures caused ribosomal pausing during D1 peptide elongation in tomato. The pause locations were non-randomly located on the D1 transcript. The interference with translation caused by ribosomal pausing allowed photodamaged PSII centers to accumulate leading to the consequent inhibition of photosynthesis.