标题：Increased Chilling Tolerance Following Transfer of a betA Gene Enhancing Glycinebetaine Synthesis in Cotton (Gossypium hirsutum L.)
作者：Zhang, Kewei; Wang, Juan; Lian, Lijun; Fan, Wenju; Guo, Ning; Lv, Sulian
作者机构：[Zhang, Kewei; Wang, Juan; Lian, Lijun; Fan, Wenju; Guo, Ning; Lv, Sulian] Minist Educ, Key Lab Plant Cell Engn & Germplasm Enhancement, Jinan 250100, 更多
通讯作者地址：[Zhang, KW]Minist Educ, Key Lab Plant Cell Engn & Germplasm Enhancement, Jinan 250100, Peoples R China.
来源：PLANT MOLECULAR BIOLOGY REPORTER
关键词：Chilling stress; Glycinebetaine; Photosynthesis; Transgenic cotton
摘要：A betA gene encoding choline dehydrogenase from Escherichia coli was transformed into cotton (Gossypium hirsutum L.) via Agrobacterium-mediated transformation. Transgenic cotton plants exhibited improved tolerance to chilling due to accumulation of glycinebetaine (GB). The results of our experiment showed that GB contents of leaves of transgenic lines 1, 3, 4, and 5, both before and after chilling stress, were significantly higher than those of wild-type (WT) plants. At 15A degrees C, transgenic lines 1, 3, 4, and 5 exhibited higher germination capacity as determined by the germination speed and final germination percentage and, displayed less inhibition in seedling shoot growth rate than WT plants. Under chilling stress, transgenic lines 4 and 5 maintained higher relative water content, upper carbon dioxide (CO2) fixation capacity and PSII electron transfer rate, better osmotic adjustment (OA), a lower percentage of ion leakage, and less lipid membrane peroxidation when compared with WT plants. Chilling resistance of the transgenic lines was demonstrated to be positively correlated with GB content under chilling stress. The high levels of GB in transgenic cotton plants might not only protect the integrity of cell membrane from chilling damage, but also be involved in OA which alleviated chilling induced water stress. Moreover, under chilling-stressed conditions, transgenic cotton plants enhanced stomatal conductance, PSII electron transport rate, and further leaf photosynthesis through accumulating high levels of GB.