Comparative transcriptome profiling provides insights into different photosynthetic responses in two tall fescue cultivars under low-light stress

Abstract Background Tall fescue ( Festuca arundinacea Schreb) is a primary cool-season forage and turfgrass, low-light (LL) stress is a primary limiting factor for turfgrass growth. Studies on two tall fescue cultivars, Arid 3 and Airlie, showed that Airlie is more susceptible to LL stress than Arid 3. However, the underlying susceptibility mechanism is obscure. Results In this study, we investigated the physiological and transcriptional changes of two tall fescue cultivars under LL stress. The two cultivars differed in growth characteristics, chlorophyll contents, photosynthetic gas exchange, and chlorophyll fluorescence. A total of 136925 unigenes were obtained from our RNA-sequencing. There were 24944 and 30816 differentially expressed genes (DEGs) between LL stress and the control in Arid 3 and Airlie, respectively. Meanwhile, there were 20599 DEGs detected between Arid 3 and Airlie under the control, and under LL stress the DEGs between two cultivars were 20783. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that the DEGs are mainly involved in ‘cell prat’ and ‘glutathione metabolism’. These results indicated that LL stress affects the expression of phytochrome-interacting factor 5 ( PIF5) , constitutively photomorphogenic 1 ( COP1) , phytochrome A ( PhyA) , and phytochrome B ( PhyB) in tall fescue, which are vital transcription factors. Genes related to chlorophyll metabolism and photosynthesis were also affected by LL stress, and were significantly differentially expressed between the two cultivars. Conclusions This study reveals two tall fescue cultivars develop different physiological and transcriptional changes to cope with LL stress, and provides an insight into different photosynthetic responses in two tall fescue cultivars responds to LL stress.