Changes in the transcriptional activity of barley plastome genes under heat shock

Abstract

Plants use a wide range of molecular reactions for adaptation of their photosynthetic apparatus to high temperature. To understand the role of plastome genes in this process, we studied transcription of photosynthetic and household genes in plastids of 7-day-old barley (Hordeum vulgare L.) seedlings and found that the genes of both groups are involved in the adaptation to heat shock. Transcription of genes encoding apoproteins of the photosystem I and photosystem II reaction centers was enhanced in 1.5 h after temperature elevation and reduced after 3 h, whereas transcription of some other genes (NADPH plastoquinone oxidoreductase, ribosomal proteins, and multisubunit RNA polymerase) was enhanced after 3 h of exposure to high temperature. Transcription of plastome genes rpl23-rpl2 and rps16 was activated by heating either the whole plant or isolated chloroplasts. This permits a supposition that changes in transcription of plastome genes occur not only due to changes in nuclear transcription of the genes encoding plastid transcription factors but also due to changes in the properties of transcription factors inside chloroplasts.