Glycine betaine (GB) plays a crucial role in plant response to abiotic stress, and its accumulation in chloroplasts is more effective than in the cytosol in improving the resistance of transgenic plants. Here, we report that the codA gene from Arthrobacter globiformis, which encodes a choline oxidase catalysing the conversion of choline to GB, was successfully introduced into the plastid genome of potato (Solanum tuberosum L.). Transgenic plants with plastid expression of codA showed increased tolerance to low temperature stress compared with the wild type (WT). Further studies revealed that under low temperature stress condition, transgenic plants presented a significantly higher photosynthetic performance by regulating the electron transport and energy distribution in PSII, and higher antioxidant enzyme activities and lower O₂^– and H₂O₂ accumulation than did the WT plants. A higher expression of the COR genes was also observed in transgenic plants. Our results suggest that chloroplast biosynthesis of GB could be an effective strategy for the engineering of plants with increased resistance to low temperature stress.

甘氨酸甜菜碱（GB）在植物对非生物胁迫的响应中起着至关重要的作用，其在叶绿体中的积累比在细胞质中的积累更有效地提高了转基因植物的抗性。在这里，我们报告说，来自球形节杆菌的codA基因已成功地导入马铃薯（Solanum tuberosum L.）的质体基因组中，该基因编码催化胆碱向GB转化的胆碱氧化酶。具有codA质体表达的转基因植物与野生型（WT）相比，对低温胁迫的耐受性增强。进一步研究表明，在低温胁迫条件下，转基因植物通过调节在PSII的电子传输和能量分布呈现的显著较高的光合性能，以及更高的抗氧化酶活性和下部O ₂ ^-和H ₂ ö ₂累积比没有野生型植物。在转基因植物中还观察到COR基因的更高表达。我们的结果表明，GB的叶绿体生物合成可能是对低温胁迫具有增强抗性的植物工程化的有效策略。