Heat stress results in incomplete C-to-U editing of maize chloroplast mRNAs and correlates with changes in chloroplast transcription rate.
The editing status rps14 and rpl20 mRNAs decreased rapidly from nearly 100% edited to about 30% edited when maize plants were shifted from 20 degrees C to 37 degrees C. A decrease in the extent of editing was easily detected within 2 h and decreased to a steady-state level of about 40% C-to-U conversion at 37 degrees C. In contrast, the editing status of these chloroplast mRNAs increased relatively slowly after plants were shifted from 37 degrees C to 20 degrees C. Chloroplasts isolated from maize plants which were grown at 20 degrees C and then shifted to 37 degrees C for 24 h were 5-10 times more transcriptionally active than chloroplasts isolated from maize plants grown continuously at 20 degrees C. Thus, the high transcription rate at 37 degrees C may establish a kinetic condition where the rate of transcription exceeds the capacity of the editing apparatus and results in incomplete editing.
Nakajima
Y
Y
Department of Developmental and Cell Biology, University of California, Irvine 92697-2300, USA.
Mulligan
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RM
D002736:Chloroplasts / Q000235:genetics*; D003596:Cytosine / Q000378:metabolism; D017343:Genes, Plant; D006358:Hot Temperature; D017393:RNA Editing / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism*; D018749:RNA, Plant / Q000378:metabolism*; D014158:Transcription, Genetic; D014529:Uridine / Q000378:metabolism; D003313:Zea mays / Q000235:genetics* / Q000502:physiology
D012333:RNA, Messenger; D018749:RNA, Plant; D003596:Cytosine; D014529:Uridine