A novel light-dependent selection marker system in plants.
Photosensitizers are common in nature and play diverse roles as defense compounds and pathogenicity determinants and as important molecules in many biological processes. Toxoflavin, a photosensitizer produced by Burkholderia glumae, has been implicated as an essential virulence factor causing bacterial rice grain rot. Toxoflavin produces superoxide and H₂O₂ during redox cycles under oxygen and light, and these reactive oxygen species cause phytotoxic effects. To utilize toxoflavin as a selection agent in plant transformation, we identified a gene, tflA, which encodes a toxoflavin-degrading enzyme in the Paenibacillus polymyxa JH2 strain. TflA was estimated as 24.56 kDa in size based on the amino acid sequence and is similar to a ring-cleavage extradiol dioxygenase in the Exiguobacterium sp. 255-15; however, unlike other extradiol dioxygenases, Mn(2+) and dithiothreitol were required for toxoflavin degradation by TflA. Here, our results suggested toxoflavin is a photosensitizer and its degradation by TflA serves as a light-dependent selection marker system in diverse plant species. We examined the efficiencies of two different plant selection systems, toxoflavin/tflA and hygromycin/hygromycin phosphotransferase (hpt) in both rice and Arabidopsis. The toxoflavin/tflA selection was more remarkable than hygromycin/hpt selection in the high-density screening of transgenic Arabidopsis seeds. Based on these results, we propose the toxoflavin/tflA selection system, which is based on the degradation of the photosensitizer, provides a new robust nonantibiotic selection marker system for diverse plants.
Koh
Serry
S
Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea.
Kim
Hongsup
H
Kim
Jinwoo
J
Goo
Eunhye
E
Kim
Yun-Jung
YJ
Choi
Okhee
O
Jwa
Nam-Soo
NS
Ma
Jun
J
Nagamatsu
Tomohisa
T
Moon
Jae Sun
JS
Hwang
Ingyu
I
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics; D015415:Biomarkers / Q000378:metabolism; D002934:Cinnamates / Q000494:pharmacology; D005798:Genes, Bacterial / Q000235:genetics; D005821:Genetic Techniques; D006921:Hygromycin B / Q000031:analogs & derivatives / Q000494:pharmacology; D008027:Light; D012275:Oryza / Q000187:drug effects / Q000235:genetics; D056507:Paenibacillus / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D010944:Plants / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects*; D030821:Plants, Genetically Modified; D011744:Pyrimidinones / Q000737:chemistry / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014170:Transformation, Genetic / Q000187:drug effects / Q000528:radiation effects; D014227:Triazines / Q000737:chemistry / Q000494:pharmacology
D015415:Biomarkers; D002934:Cinnamates; D011744:Pyrimidinones; D011993:Recombinant Fusion Proteins; D014227:Triazines; D006921:Hygromycin B; C026273:hygromycin A; C009570:toxoflavin; D017853:Phosphotransferases (Alcohol Group Acceptor); C063242:hygromycin-B kinase