Project description:Most regions of the Antarctic continent are experiencing increased dryness due to global climate change. Mosses and lichens are the dominant vegetation of the ice-free areas of Antarctica. However, the molecular mechanisms of these Antarctic plants adapting to drought stress are less documented. Here, transcriptome and metabolome analyses were employed to reveal the responses of an Antarctic moss (Pohlia nutans subsp. LIU) to drought stress. We found that drought stress made the gametophytes turn yellow and curled, and enhanced the contents of malondialdehyde and proline, and the activities of antioxidant enzymes. Totally, 2,451 differentially expressed genes (DEGs) were uncovered under drought treatment. The representative DEGs are mainly involved in ROS-scavenging and detoxification, flavonoid metabolism pathway, plant hormone signaling pathway, lipids metabolism pathway, transcription factors and signal-related genes. Meanwhile, a total of 354 differentially changed metabolites (DCMs) were detected in the metabolome analysis. Flavonoids and lipids were the most abundant metabolites and they accounted for 41.53% of the significantly changed metabolites. In addition, integrated transcriptome and metabolome analyses revealed co-expression patterns of flavonoid and long-chain fatty acid biosynthesis genes and their metabolites. Finally, qPCR analysis demonstrated that the expression levels of stress-related genes were significantly increased. These genes included those involved in ABA signaling pathway (NCED3, PP2C, PYL, and SnAK2), jasmonate signaling pathway (AOC, AOS, JAZ, and OPR), flavonoid pathway (CHS, F3',5'H, F3H, FLS, FNS, and UFGT), antioxidant and detoxifying functions (POD, GSH-Px, Prx and DTX), and transcription factors (ERF and DREB). In summary, we speculated that P. nutans were highly dependent on ABA and jasmonate signaling pathways, ROS scavenging, flavonoids and fatty acid metabolism in response to drought stress. These findings present an important knowledge for assessing the impact of coastal climate change on Antarctic basal plants.
Project description:This experiment probed for the presence of known Arabidopsis and rice microRNAs in total RNA samples derived from species representative of the major groups of land plants: Eudicots (Arabidopsis thaliana, Nicotiana benthamiana), monocots (Oryza satica, Triticum aestivum), magnoliids (Liriodendron tulipifera), gymnosperms (Pinus resinosa), ferns (Ceratopteris thalictroides), lycopods (Selaginella uncinata), and mosses (Polytrichum juniperinum). In most cases two technical or biological replicates were performed.
Project description:The colonization of land by plants relies on numerous evolutionary innovations crucial for terrestrial adaptation. These include advances in sexual reproduction and the ability to properly respond to various environmental stresses, which involve precise control of their regulatory genes. A notable genetic innovation in land plants is the emergence of histone lysine methyltransferases ATXR5/6, which specifically catalyse the repressive histone H3 lysine 27 monomethylation (H3K27me1). However, the evolutionary reason for land plants to develop these enzymes remains unclear. In this study, we investigate the importance of ATXR5/6 by generating strong atxr5;axtr6 double mutants in Arabidopsis. Our results show that ATXR5/6 are essential for plant reproductive development and play a critical role in supporting normal plant growth by repressing the transcription of stress responsive genes. In addition, ATXR5/6 are necessary for maintaining H3K27 trimethylation (H3K27me3), likely by providing H3K27me1 as a substrate for further methylation. We also demonstrate that the function of ATXR5/6 in regulating reproductive development and responsive genes is conserved in the monocot rice. We propose that land plants may have evolved ATXR5/6 to assist in the transcriptional regulation necessary for terrestrial adaptation