Production components in transformed and untransformed ‘Micro-Tom’ tomato plants

ABSTRACT Changes to the amounts of certain proteins have resulted in several studies, among them the so-called heat shock proteins (HSP), which take many forms, most of them constitutive. However, other forms may be inducible by a particular stress factor. The ‘Micro-Tom’ tomato is considered a model for experimental studies due to having suitable characteristics, such as reduced size, short generation time, and ease of transformation. Growth and production components were therefore evaluated in ‘Micro-Tom’ tomato plants transformed for different levels of mitochondrial HSP (MT-sHSP23.6). Plants from genotypes of the ‘Micro-Tom’ tomato (untransformed, and transformed with overexpression and with expression silencing) were grown under controlled conditions of temperature, photoperiod and photon flux density. To obtain the data, successive collections were carried out at regular intervals (21 days) throughout the development cycle of the plants, starting from the 21st day after transplanting (DAT). Total dry matter, leaf area, dry-weight partitioning between the plant organs, and production components were determined in the three genotypes. From interpretation of the results, it was found that plants transformed with overexpression of MT-sHSP23.6 displayed greater production capacity, considering the fresh weight of the fruit; but in general, the data showed that genetic transformation did not bring about major changes in growth, since the three genotypes displayed similar behaviour.摘要：特定蛋白质的含量变化催生了多项相关研究，其中便包括热激蛋白（heat shock proteins, HSP）家族。该家族蛋白存在多种亚型，多数为组成型表达，而其余亚型则可被特定胁迫因子诱导表达。‘Micro-Tom’番茄因具备植株体型小巧、生长周期短且易于遗传转化等优良特性，被广泛用作实验研究的模式植物。本研究针对线粒体热激蛋白（mitochondrial HSP, MT-sHSP23.6）的不同表达水平，对经遗传转化的‘Micro-Tom’番茄植株的生长与产量相关性状展开了评估。实验所用的‘Micro-Tom’番茄基因型包含三类：未转化对照株系、过表达转化株系以及基因表达沉默转化株系，所有植株均在可控的温度、光周期及光量子通量密度条件下进行培养。为获取完整实验数据，本研究自植株移栽后第21天（days after transplanting, DAT）起，于整个生长周期内每隔21天开展一次连续采样。研究人员对三类基因型植株的总干物质含量、叶面积、植株各器官干物质分配比例以及产量相关性状进行了测定。结果分析显示，过表达MT-sHSP23.6的转化株系在果实鲜重维度上具备更高的生产能力；但整体而言，实验数据表明遗传转化并未对植株生长造成显著改变，三类基因型的生长表现并无明显差异。