Université de Toulouse, Institut National Polytechnique-Ecole Nationale Supérieure Agronomique de Toulouse, Génomique et Biotechnologie des Fruits, Castanet-Tolosan F-31326, France.
Plant Physiol. 2012 Oct;160(2):708-25. doi: 10.1104/pp.112.203679. Epub 2012 Aug 20.
A comparative proteomic approach was performed to identify differentially expressed proteins in plastids at three stages of tomato (Solanum lycopersicum) fruit ripening (mature-green, breaker, red). Stringent curation and processing of the data from three independent replicates identified 1,932 proteins among which 1,529 were quantified by spectral counting. The quantification procedures have been subsequently validated by immunoblot analysis of six proteins representative of distinct metabolic or regulatory pathways. Among the main features of the chloroplast-to-chromoplast transition revealed by the study, chromoplastogenesis appears to be associated with major metabolic shifts: (1) strong decrease in abundance of proteins of light reactions (photosynthesis, Calvin cycle, photorespiration) and carbohydrate metabolism (starch synthesis/degradation), mostly between breaker and red stages and (2) increase in terpenoid biosynthesis (including carotenoids) and stress-response proteins (ascorbate-glutathione cycle, abiotic stress, redox, heat shock). These metabolic shifts are preceded by the accumulation of plastid-encoded acetyl Coenzyme A carboxylase D proteins accounting for the generation of a storage matrix that will accumulate carotenoids. Of particular note is the high abundance of proteins involved in providing energy and in metabolites import. Structural differentiation of the chromoplast is characterized by a sharp and continuous decrease of thylakoid proteins whereas envelope and stroma proteins remain remarkably stable. This is coincident with the disruption of the machinery for thylakoids and photosystem biogenesis (vesicular trafficking, provision of material for thylakoid biosynthesis, photosystems assembly) and the loss of the plastid division machinery. Altogether, the data provide new insights on the chromoplast differentiation process while enriching our knowledge of the plant plastid proteome.
采用比较蛋白质组学方法鉴定了番茄（Solanum lycopersicum）果实成熟（绿熟、转色、红熟）过程中质体中差异表达的蛋白质。对三个独立重复实验的数据进行严格的整理和处理，鉴定出 1932 种蛋白质，其中 1529 种通过光谱计数进行定量。通过对六个代表不同代谢或调节途径的蛋白质的免疫印迹分析，对定量程序进行了后续验证。该研究揭示的质体到叶绿体的转变的主要特征之一是，叶绿体发育与主要代谢转变有关：（1）在转色和红熟阶段之间，光反应（光合作用、卡尔文循环、光呼吸）和碳水化合物代谢（淀粉合成/降解）的蛋白质丰度明显降低；（2）萜类生物合成（包括类胡萝卜素）和应激响应蛋白（抗坏血酸-谷胱甘肽循环、非生物胁迫、氧化还原、热休克）增加。这些代谢变化之前是质体编码的乙酰辅酶 A 羧化酶 D 蛋白的积累，这解释了产生将积累类胡萝卜素的储存基质的原因。值得注意的是，大量参与提供能量和代谢物输入的蛋白质。质体的结构分化的特点是类囊体蛋白的急剧和连续减少，而包膜和基质蛋白仍然非常稳定。这与类囊体和光系统生物发生的机器（囊泡运输、类囊体生物合成的物质供应、光系统组装）的破坏以及质体分裂机器的丧失相一致。总的来说，这些数据为叶绿体分化过程提供了新的见解，同时丰富了我们对植物质体蛋白质组的认识。
