College of Life Science, State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Taian, 271018, China.
Department of Horticulture, ALS 4017, Oregon State University, Corvallis, OR, 97331, USA.
Plant Sci. 2019 Mar;280:355-366. doi: 10.1016/j.plantsci.2018.12.023. Epub 2019 Jan 2.
Glycinebetaine has been widely considered as an effective protectant against abiotic stress in plants, and also found to promote plant growth under normal growing conditions, especially during the reproductive stage. Betaine aldehyde dehydrogenase (BADH) and choline oxidase (COD) are two key enzymes which have been used to confer glycinebetaine synthesis in plant which normally does not synthesis glycinebetaine. In this study, we used the tomato (Solanum lycopersicum, cv 'Moneymaker') plants of wild-type and the transgenic lines codA (L1, L2) and BADH (2, 46), which were transformed with codA and BADH, respectively, to study the impact of glycinebetaine on tomato fruit development. Our results showed that the codA and BADH transgenes induced the formation of enlarged flowers and fruits in transgenic tomato plants. In addition, the transgenic tomato plants had a higher photosynthetic rate, higher assimilates content, and higher leaf chlorophyll content than the wild-type plants. We also found that the enlargement of fruit size was related to the contents of phytohormones, such as auxin, brassinolide, gibberellin, and cytokinin. Additionally, qPCR results indicated that the expressions levels of certain genes related to fruit growth and development were also elevated in transgenic plants. Finally, transcriptome sequencing results revealed that the differences in the levels of gene expression in tomato fruit between the transgenic and wild-type plants were observed in multiple pathways, predominantly those of photosynthesis, DNA replication, plant hormone signal transduction, and biosynthesis. Taken together, our results suggest that glycinebetaine promotes tomato fruit development via multiple pathways. We propose that genetic engineering of glycinebetaine synthesis offers a novel approach to enhance the productivity of tomato and other crop plants.
甘氨酸甜菜碱被广泛认为是植物抗逆的有效保护剂，也被发现可促进正常生长条件下植物的生长，尤其是在生殖阶段。甜菜碱醛脱氢酶（BADH）和胆碱氧化酶（COD）是两种关键酶，它们被用于在通常不合成甘氨酸甜菜碱的植物中赋予甘氨酸甜菜碱合成。在这项研究中，我们使用了野生型和转 codA（L1、L2）和 BADH（2、46）基因的番茄（Solanum lycopersicum，cv 'Moneymaker'）植物系，分别转 codA 和 BADH 基因，以研究甘氨酸甜菜碱对番茄果实发育的影响。我们的结果表明，codA 和 BADH 转基因诱导了转基因番茄植物花和果实的增大。此外，与野生型植物相比，转基因番茄植物具有更高的光合速率、更高的同化产物含量和更高的叶片叶绿素含量。我们还发现，果实大小的增大与植物激素如生长素、油菜素内酯、赤霉素和细胞分裂素的含量有关。此外，qPCR 结果表明，与果实生长和发育相关的某些基因的表达水平在转基因植物中也升高了。最后，转录组测序结果表明，在多个途径中，包括光合作用、DNA 复制、植物激素信号转导和生物合成，观察到转基因和野生型番茄果实中基因表达水平的差异。综上所述，我们的结果表明，甘氨酸甜菜碱通过多种途径促进番茄果实发育。我们提出，通过基因工程合成甘氨酸甜菜碱为提高番茄和其他作物的生产力提供了一种新方法。
