Transcriptomics Integrated With Metabolomics Reveal the Effects of Ultraviolet-B Radiation on Flavonoid Biosynthesis in Antarctic Moss

Abstract

Bryophytes are the dominant vegetation in the Antarctic continent. They have suffered more unpleasant ultraviolet radiation due to the Antarctic ozone layer destruction. However, it remains unclear about the molecular mechanism of Antarctic moss acclimation to UV-B light. Here, the transcriptomics and metabolomics approaches were conducted to uncover transcriptional and metabolic profiling of the Antarctic moss Leptobryum pyriforme under UV-B radiation. Totally, 67,290 unigenes with N50 length of 2,055 bp were assembled. Of them, 1,594 unigenes were significantly up-regulated and 3353 unigenes were markedly down-regulated under UV-B radiation. These differentially expressed genes (DEGs) involved in UV-B signaling, flavonoid biosynthesis, ROS scavenging, and DNA repair. In addition, a total of 531 metabolites were detected, while flavonoids and anthocyanins accounted for 10.36% of the total compounds. There were 49 upregulated metabolites and 41 downregulated metabolites under UV-B radiation. Flavonoids were the most significantly changed metabolites. qPCR analysis showed that UVR8-COP1-HY5 signaling pathway genes and photolyase genes (i.e., LpUVR3, LpPHR1, and LpDPL) were significantly up-regulated under UV-B light. In addition, the expression levels of JA signaling pathway-related genes (i.e., OPR and JAZ) and flavonoid biosynthesis-related genes were also significantly increased under UV-B radiation. The integrative data analysis showed that UVR8-mediated signaling, jasmonate signaling, flavonoid biosynthesis pathway and DNA repair system might contribute to L. pyriforme acclimating to UV-B radiation. Therefore, these findings present a novel knowledge for understanding the adaption of Antarctic moss to polar environments and provide a foundation for assessing the impact of global climate change on Antarctic land plants.

Integrated transcriptome and metabolome analyses reveal the adaptation of Antarctic moss Pohlia nutans to drought stress

“…The Antarctic terrestrial and maritime ecosystem suffers from a variety of harsh climatic conditions like extreme dryness, low temperature, high UV-B radiation, extremely short growing season, all of which severely limit the growth and development of plants ( Convey and Peck, 2019 ; Perera-Castro et al, 2021 ; Liu et al, 2021b ). Lichens and bryophytes as well as two native Antarctic vascular plants Deschampsia antarctica and Colobanthus quitensis dominate the vegetations of Antarctica Peninsula ( Robinson et al, 2010 ).…”

A Moss 2-Oxoglutarate/Fe(II)-Dependent Dioxygenases (2-ODD) Gene of Flavonoids Biosynthesis Positively Regulates Plants Abiotic Stress Tolerance

“…However, some 2-ODD genes from S. moellendorffii and P. patens were also annotated as probable ANS. Furthermore, six anthocyanin compounds including peonidin 3-O-glucoside chloride, peonidin O-hexoside, pelargonidin, malvidin 3-O-glucoside, cyanidin 3-O-galactoside, and cyanidin 3-O-rutinoside were recently confirmed to be present in Antarctic moss Leptobryum pyriforme by a widely targeted metabolomics, and cyanidin 3-O-rutinoside was the significantly up-regulated metabolite with log2(Fold change) 14.68 under ultraviolet-B radiation (Liu et al, 2021).…”

The Antarctic Moss Pohlia nutans Genome Provides Insights Into the Evolution of Bryophytes and the Adaptation to Extreme Terrestrial Habitats

“…Similarly, a significant increase was found in biological activity over the past 50 years, measured through moss growth or accumulation rates (Amesbury et al, 2017). Currently, Antarctic plants appears to be promising models for studying the adaptation mechanism to various abiotic stresses (Convey and Peck, 2019;Perera-Castro et al, 2020;Bertini et al, 2021;Liu et al, 2021) and monitoring the regional climate changes (Amesbury et al, 2017;Lee et al, 2017;Robinson et al, 2018;Cannone et al, 2022) as well as assessing the impact of human activities (Malenovský et al, 2015;Hughes et al, 2020). Particularly, the genomic features were widely clarified in the Antarctic bacteria (Benaud et al, 2021), algae (Zhang et al, 2020b), and fishes (Kim et al, 2019), but the underpinnings remain unclear in the adaptation of mosses to extreme environments.…”

“…The field experiments demonstrated that continuing UV-B radiation reduced the chlorophyll contents in the Antarctic moss (Bryum argenteum) and lichen (Umbilicaria aprina), and increased the contents of UV-B absorbing compounds (Singh and Singh, 2014). The Multi-omics analysis indicated that UVR8-mediated signaling, flavonoid biosynthesis, and DNA repair machinery might facilitate the adaptation of Antarctic moss to UV-B radiation Liu et al, 2021). The moderate moss Physcomitrella patens was more qualified of surviving UV-B radiation than Arabidopsis, and several flavonoid biosynthesis genes were also markedly upregulated in response to UV-B radiation (Wolf et al, 2010).…”

“…TL20W/01RS narrowband UV-B tubes were used for UV-B light source as described previously (Wolf et al, 2010;Liu et al, 2021). Mosses without treatments or treated with sterile water were used as control group.…”