TY - JOUR
T1 - A tobacco plastidal transit sequence cannot override the dual targeting capacity of Myxococcus xanthus protoporphyrinogen oxidase in transgenic rice
AU - Jung, S.
AU - Lee, Y.
AU - Back, K.
PY - 2006/9
Y1 - 2006/9
N2 - The effect of a plastidal transit sequence in Myxococcus xanthus protoporphyrinogen oxidase (Protox) on gene targeting ability was investigated by generating transgenic rice that overexpressed M. xanthus Protox with the additional plastidal transit sequence (TTS line). In transgenic lines TTS3 and TTS4, the Protox antibody cross-reacted with the mature M. xanthus Protox protein of 50 kDa. In an in vitro import system using the M. xanthus Protox gene with the plastidal transit sequence, M. xanthus protein was detected in both chloroplasts and mitochondria, confirming that it was targeted into both organelles, as in transgenic rice line, M4, that overexpressed M. xanthus Protox lacking the plastidal transit sequence. A prominent increase in chloroplastic and mitochondrial Protox activity was observed in TTS3 and TTS4 relative to the wild type. However, the increase was lower than that in transgenic line M4. Seeds from all transgenic lines (TTS3, TTS4, and M4) were able to germinate when treated with up to 500 μM of the Protox-inhibiting herbicide, oxyfluorfen, whereas seeds from the wild type failed to germinate even when treated at levels as low as 1 μM. After foliar application of oxyfluorfen, TTS3 and TTS4 exhibited a reduced Protox activity, however, it was much greater than uninhibited Protox activity of wild type. The great increase in conductivity was followed by the great accumulation of photodynamic protoporphyrin IX only in oxyfluorfen-treated wild-type plants, not in oxyfluorfen-treated TTS lines. The presence of the plastidal transit sequence neither excludes the intrinsic ability of subcellular translocation of M. xanthus Protox nor changes herbicide resistance in TTS lines.
AB - The effect of a plastidal transit sequence in Myxococcus xanthus protoporphyrinogen oxidase (Protox) on gene targeting ability was investigated by generating transgenic rice that overexpressed M. xanthus Protox with the additional plastidal transit sequence (TTS line). In transgenic lines TTS3 and TTS4, the Protox antibody cross-reacted with the mature M. xanthus Protox protein of 50 kDa. In an in vitro import system using the M. xanthus Protox gene with the plastidal transit sequence, M. xanthus protein was detected in both chloroplasts and mitochondria, confirming that it was targeted into both organelles, as in transgenic rice line, M4, that overexpressed M. xanthus Protox lacking the plastidal transit sequence. A prominent increase in chloroplastic and mitochondrial Protox activity was observed in TTS3 and TTS4 relative to the wild type. However, the increase was lower than that in transgenic line M4. Seeds from all transgenic lines (TTS3, TTS4, and M4) were able to germinate when treated with up to 500 μM of the Protox-inhibiting herbicide, oxyfluorfen, whereas seeds from the wild type failed to germinate even when treated at levels as low as 1 μM. After foliar application of oxyfluorfen, TTS3 and TTS4 exhibited a reduced Protox activity, however, it was much greater than uninhibited Protox activity of wild type. The great increase in conductivity was followed by the great accumulation of photodynamic protoporphyrin IX only in oxyfluorfen-treated wild-type plants, not in oxyfluorfen-treated TTS lines. The presence of the plastidal transit sequence neither excludes the intrinsic ability of subcellular translocation of M. xanthus Protox nor changes herbicide resistance in TTS lines.
KW - Herbicide resistance
KW - Oxyfluorfen
KW - Protoporphyrin IX
KW - Protoporphyrinogen oxidase
KW - Transgenic rice
UR - http://www.scopus.com/inward/record.url?scp=33746716770&partnerID=8YFLogxK
U2 - 10.1016/j.pestbp.2005.11.010
DO - 10.1016/j.pestbp.2005.11.010
M3 - Article
AN - SCOPUS:33746716770
SN - 0048-3575
VL - 86
SP - 49
EP - 56
JO - Pesticide Biochemistry and Physiology
JF - Pesticide Biochemistry and Physiology
IS - 1
ER -