RNA editing analysis of some chloroplast transcripts and its response to light and salt stress in Mesona chinensis Benth

To study the effects of light quality and salt stress on RNA editing of Mesona chinensis Benth (MCB) chloroplast genome, the RNA editing sites in the MCB chloroplast protein-coding genes were predicted and then partially verified by PCR and RT-PCR. Meanwhile, the RNA editing efficiency and relative expression of accD, ndhB, ndhF, and rpoB under red and blue light and salt stress conditions were analyzed. A total of 45 editing sites were predicted and all the editing sites were C-to-U conversion. 12 predicted editing sites were verified. The expression level of accD was down-regulated under red light compared with the blue light, as well as down-regulated under salt stress compared with the normal condition (CK). Additionally, the editing efficiency of accD-287 was 96.7% under normal condition, higher than that under salt stress (93.3%) but lower than those under blue and red light (both 100%). In ndhB, ndhB-494 was partially edited under normal growth condition but completely edited under blue and red light and salt stress, and other sites were completely edited under all conditions. It was indicated that the editing frequency was not positively relevant to the transcript level. Besides, accD-287 and ndhB-494 might be involved in response to salt stress.