Plant dehydration-responsive element binding (DREB) transcription factors (TFs) play important roles during stress tolerance by regulating the expression of numerous genes involved in stresses. DREB TFs have been extensively studied in a variety of angiosperms and bryophytes. To date, no information on the identification and characterization of DREB TFs in Dicranum scoparium has been reported. In this study, a new DBF1 gene from D. scoparium was identified by cloning and sequencing. Analysis of the conserved domain and physicochemical properties revealed that DsDBF1 protein has a classic AP2 domain encoding a 238 amino acid polypeptide with a molecular mass of 26 kDa and a pI of 5.98. Subcellular prediction suggested that DsDBF1 is a nuclear and cytoplasmic protein. Phylogenetic analysis showed that DsDBF1 belongs to group A-5 DREBs. Expression analysis by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) revealed that DsDBF1 was significantly upregulated in response to abiotic stresses such as desiccation/rehydration, exposure to paraquat, CdCl₂, high and freezing temperatures. Taken together, our data suggest that DsDBF1 could be a promising gene candidate to improve stress tolerance in crop plants, and the characterization of TFs of a stress tolerant moss such as D. scoparium provides a better understanding of plant adaptation mechanisms.

In the present work, the APX gene encoding ascorbate peroxidase in the moss Dicranum scoparium was for the first time cloned and sequenced, and a high homology of APX with ascorbate peroxidase genes of the mosses Grimmia pilifera and Physcomitrella patens was shown. The structure of the protein was characterized using bioinfomatics approach, and the activity of the enzyme under abiotic stresses was studied. An increase in the activity of ascorbate peroxidase was detected during desiccation of D. scoparium shoots. When exposed to heat shock, a decrease in the activity of ascorbate peroxidase correlated with a decrease in the expression of APX. Conserved elements, which were found in the structure of ascorbate peroxidase gene and protein, indicate that these sequences are conserved in the plant genome during evolution, in support of the importance of this enzyme in maintaining cellular redox status.

Currently, due to the increasing impact of anthropogenic factors and changes in solar activity, the temperature on Earth is rising, posing a threat to biodiversity. Lichens are among the most sensitive organisms to climate change. Elevated ambient temperatures can have a significant impact on lichens, resulting in more frequent and intense drying events that can impede metabolic activity. It has been suggested that the possession of a diverse sterol composition may contribute to the tolerance of lichens to adverse temperatures and other biotic and abiotic stresses. The major sterol found in lichens is ergosterol (ERG); however, the regulation of the ERG biosynthetic pathway, specifically the step of epoxidation of squalene to 2,3-oxidosqualene catalyzed by squalene epoxidase during stress, has not been extensively studied. In this study, we used lichen Lobaria pulmonaria as a model species that is well known to be sensitive to air pollution and habitat loss. Using in silico analysis, we identified cDNAs encoding squalene epoxidase from L. pulmonaria, designating them as LpSQE1 for the mycobiont and SrSQE1 for the photobiont Symbiochloris reticulata. Our results showed that compared with a control kept at room temperature (+20 °C), mild temperatures (+4 °C and +30 °C) did not affect the physiology of L. pulmonaria, assessed by changes in membrane integrity, respiration rates, and PSII activity. An extreme negative temperature (−20 °C) noticeably inhibited respiration but did not affect membrane stability. In contrast, treating lichen with a high positive temperature (+40 °C) significantly reduced all physiological parameters. Quantitative PCR analysis revealed that exposing thalli to −20 °C, +4 °C, +30 °C, and +40 °C stimulated the expression levels of LpSQE1 and SrSQE1 and led to a significant upregulation of Hsps. These data provide new information regarding the roles of sterols and Hsps in the response of lichens to climate change.

Fusarium oxysporum f. sp. radicis-cucumerinum (Forc) V03-2g and Fusarium oxysporum f. sp. radicis-lycopersici (Forl) ZUM2407 both cause foot and root rot in cucumber, but differ in host range. Forc V03-2g possesses Secreted in Xylem (SIX) effector genes, whereas Forl ZUM2407 does not, raising questions about their distinct infection strategies on this host. Using comparative transcriptomic analysis (in cucumber at 7 and 14 days post-inoculation (dpi) and in tomato at 2 dpi) we show that Forl ZUM2407 induces a delayed defense response in cucumber compared to Forc V03-2g. In turn, Forc V03-2g rapidly activates accessory chromosome effectors on cucumber, while Forl ZUM2407 initially deploys core chromosome genes, activating distinct from Forc V03-2g accessory genes only by 14 dpi. Thereby, Forc V03-2g and Forl ZUM2407 use distinct accessory gene repertoires (unique to each strain) and distinct core gene transcription strategies to infect the same host.