作者：Benyon, L. S.,Stover, E.,Bowman, K. D.,Niedz, R.,Shatters, R. G.,Zale, J., Belknap, W.
作者单位：US Horticultural Research Laboratory, USDA/ARS,Western Regional Research Center, USDA/ARS
摘要：Transgenic solutions are being widely explored to develop huanglongbing (HLB) resistance in citrus. A critical component of a transgenic construct is the promoter, which determines tissue specificity and level of target gene expression. This study compares the characteristics of five promoters regulating the beta-glucuronidase (GUS) reporter gene in the trifoliate hybrid rootstock US-802. Two of the selected promoters direct high levels of constitutive transgene expression in other dicotyledonous plants: 2X35S, the tandem-repeat promoter of the cauliflower mosaic virus 35S gene and bul409S, a truncation of the potato polyubiquitin promoter. Because Candidatus Liberibacter, the Gram-negative bacterium associated with HLB, infects only the phloem tissue, it may be advantageous to limit transgene expression to the vascular tissue and reduce expression in the fruit. Thus, we also tested three promoters that demonstrate phloem specificity when transformed and expressed in other plants: WDV, from wheat dwarf geminivirus; AtSUC2, the sucrose-H+ symporter gene promoter from Arabidopsis; and CsSUS, the sucrose synthase promoter from citrus. Histochemical staining for GUS activity was observed throughout leaf and stem tissues for the constitutive promoters, while the three phloem-specific promoters largely showed the expected tissue-specific staining. Expression of GUS in some individual transformants with promoters CsSUS and WDV appeared leaky, with some laminar tissue staining. Relative quantification of qRT-PCR data revealed a wide range of mRNA abundance from transgenics with each of the five promoters. Fluorometry also revealed that GUS activity differed depending on the promoter used, but mRNA levels and enzyme activity were not highly correlated.
关键词：Beta-glucuronidase,Genetic engineering,HLB, Transgenics, transgenic plants ,
文献注录：Benyon, L. S.,Stover, E.,Bowman, K. D.,Niedz, R.,Shatters, R. G.,Zale, J., Belknap, W. . GUS expression driven by constitutive and phloem-specific promoters in citrus hybrid US-802 [J]. In Vitro Cellular & Developmental Biology - Plant. 2013, 03: 255-265.
报/刊名：《In Vitro Cellular & Developmental Biology - Plant》，发表于2013 / 第 03 期。
文献类型： [J]
页码：第 255-265 页 / 共11 页