Identification of cis-elements conferring high levels of gene expression in non-green plastids.
Although our knowledge about the mechanisms of gene expression in chloroplasts has increased substantially over the past decades, next to nothing is known about the signals and factors that govern expression of the plastid genome in non-green tissues. Here we report the development of a quantitative method suitable for determining the activity of cis-acting elements for gene expression in non-green plastids. The in vivo assay is based on stable transformation of the plastid genome and the discovery that root length upon seedling growth in the presence of the plastid translational inhibitor kanamycin is directly proportional to the expression strength of the resistance gene nptII in transgenic tobacco plastids. By testing various combinations of promoters and translation initiation signals, we have used this experimental system to identify cis-elements that are highly active in non-green plastids. Surprisingly, heterologous expression elements from maize plastids were significantly more efficient in conferring high expression levels in root plastids than homologous expression elements from tobacco. Our work has established a quantitative method for characterization of gene expression in non-green plastid types, and has led to identification of cis-elements for efficient plastid transgene expression in non-green tissues, which are valuable tools for future transplastomic studies in basic and applied research.
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany.
Jiang
J
Zhang
Stephanie
S
Ruf
Claudia
C
Hasse
Liam
L
Childs
Lars B
LB
Scharff
Ralph
R
Bock
D020121:5' Untranslated Regions / Q000235:genetics*; D015870:Gene Expression / Q000235:genetics*; D017930:Genes, Reporter; D005819:Genetic Markers; D005822:Genetic Vectors; D054627:Genome, Plastid; D007612:Kanamycin / Q000494:pharmacology; D007613:Kanamycin Resistance / Q000235:genetics*; D009928:Organ Specificity; D010641:Phenotype; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D018087:Plastids / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D019076:Transgenes; D003313:Zea mays / Q000235:genetics
D020121:5' Untranslated Regions; D005819:Genetic Markers; D012333:RNA, Messenger; D018749:RNA, Plant; D007612:Kanamycin