| dc.description.abstract | Plants can be genetically modified (termed transgenic plants) to meet special needs, such as increased resistance to extreme weather, increased nutritious values, or the production of the useful compounds. These often involve the expression of endogenous or exogenous genes under the control of chosen promoters. Cauliflower mosaic virus (CaMV) 35S is one of the promoters commonly used. However, genes driven by the foreign 35S promoter often suffer from gene silencing after the transgenic plants grow for a few generations, greatly hampers the stable application of transgenic plants produced. Therefore, there are urgent needs of identifying stable promoters that can replace 35S. For this purpose, we selected and experimentally tested the strength and stability of 5 endogenous promoters in Arabidopsis in 2nd (T2) to 5th (T5) generations of transgenic plants. Our results revealed that promoters AT4G05320 (UBQ10), AT5G60390 (EF1α), AT4G31700 (RPS6a), and AT1G13320 (PP2A) have ubiquitous activities and can drive stable expression of the reporter gene eGFP in T2 to T5 generations of the transgenic lines. Among them, promoter strength of EF1α and UBQ10 is similar to that of 35S thus are optimal candidates to replace 35S. RPS6a, and PP2A promoters, on the other hand, have intermediate to low activities, allowing for versatile choices in expressing transgenes of interests. Unexpectedly, the reporter gene driven by one of the promoters selected, AT1G13440 (GAPC2), also exhibited gene silencing behaviors when transgenic plants were propagated for several generations. This indicated that both origin endogenous (which construct from endogenous promoters) and heterologous (such as 35S) promoters can elicit gene silencing in transgenic plants. In conclusion, our study revealed alternative choices of plant promoters with expression stability and wide-range of activities for generating transgenic plants. | en_US |