02444naa a2200277 a 450000100080000000500110000800800410001902400520006010000200011224501200013226000090025252016110026165000200187265000190189265300160191165300130192765300270194065300190196765300160198670000190200270000180202170000190203970000180205870000220207677300680209821649052024-08-02       2024    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1007/s11240-024-02796-42DOI1 aMONTEIRO, T. R.  aEvaluation of two new promoters to express transgenes stably in lettuce (Lactuca sativa L.).h[electronic resource]  c2024  aSeveral studies suggest that transgene expression in lettuce may be unstable, possibly as a result of epigenetic silencing of the cauliflower mosaic virus 35 S RNA promoter (35SCaMV). To solve this problem, the ACT2 promoter from Arabidopsis thaliana (pAtACT2) and the novel SlAVP1 promoter from Solanum lycopersicum (pSlAVP1) were evaluated to express the gus reporter gene in lettuce plants. Three generations of genetically modified plants were evaluated using histochemical and fluorometric GUS assays. The results demonstrated that the GUS activity of plants expressing gus under the control of the pAtACT2 and pSlAVP1 promoters was higher and more stable than that of plants expressing the gus gene under the control of the 35SCaMV promoter. It was observed in different mature and immature tissues and organs, such as seeds, cotyledons, leaves, stems, roots and flowers. This demonstrated that the alternative promoters, pAtACT2 and pSlAVP1, have the potential to direct constitutive expression in lettuce leaf tissues and achieve more stable transgene expression. In addition, the study also explored the reactivation of transgene expression in 35SCaMV plants treated with 5-azacytidine, a compound known to affect DNA methylation and potentially reverse epigenetic silencing. The results indicated that transgene expression in 35SCaMV plants could be reactivated with 5-azacytidine treatment. These results suggest that the alternative promoters pAtACT2 and pSlAVP1 are superior to the conventional 35SCaMV promoter for achieving more stable and elevated levels of transgene expression in lettuce.  aDNA methylation  aGene silencing  aAtACT2 gene  aGus gene  aLettuce transformation  aOverexpression  aSlAVP1 gene1 aQUEIROZ, L. N.1 aCABRAL, G. B.1 aCITADIN, C. T.1 aSANTOS, M. P.1 aARAGÃO, F. J. L.  tPlant Cell, Tissue and Organ Culture (PCTOC)gv. 157, 71, 2024.