The specific glycerolipid composition is responsible for maintaining the membrane stability of Physcomitrella patens under dehydration stress

The dehydration-responsive protein PpFAS1.3 in moss Physcomitrium patens plays a regulatory role in lipid metabolism

Moss plants appear in the early stages of land colonization and possess varying degrees of dehydration tolerance. In this study, a protein called PpFAS1.3 was identified, which contains a fasciclin 1-like domain and is essential for the moss Physcomitrium patens' response to short-term rapid dehydration. When the FAS1.3 protein was knocked out, leafyshoots showed a significant decrease in tolerance to rapid dehydration, resulting in accelerated water loss and increased membrane leakage. Phylogenetic analysis suggests that PpFAS1.3 and its homologous proteins may have originated from bacteria and are specifically found in non-vascular plants like mosses and liverworts. As a dehydration-related protein, FAS1.3 plays a significant role in regulating lipid metabolism, particularly in the synthesis of free fatty acids (FFA) and the metabolism of two phospholipids, PC and PA. This discovery highlights the close connection between PpFAS1.3 and lipid metabolism, providing new insights into the molecular mechanisms underlying plant adaptation to stresses.

Dynamic Regulation of Lipid Droplet Biogenesis in Plant Cells and Proteins Involved in the Process

Lipid droplets (LDs) are ubiquitous, dynamic organelles found in almost all organisms, including animals, protists, plants and prokaryotes. The cell biology of LDs, especially biogenesis, has attracted increasing attention in recent decades because of their important role in cellular lipid metabolism and other newly identified processes. Emerging evidence suggests that LD biogenesis is a highly coordinated and stepwise process in animals and yeasts, occurring at specific sites of the endoplasmic reticulum (ER) that are defined by both evolutionarily conserved and organism- and cell type-specific LD lipids and proteins. In plants, understanding of the mechanistic details of LD formation is elusive as many questions remain. In some ways LD biogenesis differs between plants and animals. Several homologous proteins involved in the regulation of animal LD formation in plants have been identified. We try to describe how these proteins are synthesized, transported to the ER and specifically targeted to LD, and how these proteins participate in the regulation of LD biogenesis. Here, we review current work on the molecular processes that control LD formation in plant cells and highlight the proteins that govern this process, hoping to provide useful clues for future research.

Flavonoids from Sedum aizoon L. inhibit Botrytis cinerea by negatively affecting cell membrane lipid metabolism

Botrytis cinerea is a highly destructive and widespread phytopathogen in fruits. The widespread use of chemical antifungal agents on fruits has aided in disease control while their long-term use has resulted in the emergence of resistant fungal strains. Flavonoids have a specific antifungal effect. The inhibitory effect and underlying mechanism of flavonoids from Sedum aizoon L. (FSAL) on B. cinerea were determined in this study. The results showed that the minimum inhibitory concentration of FSAL against B. cinerea was 1.500 mg/mL. FSAL treatment caused leakage of macromolecules such as nucleic acids, led to accumulation of malondialdehyde and relative oxygen species, and disrupted the ultrastructure of B. cinerea. The transcriptome results indicated that compared with the control group, there were 782 and 1330 genes identified as being substantially upregulated and downregulated, respectively, in the FSAL-treated group. The identified genes and metabolites were mostly involved in redox processes and glycerolipid and amino acid metabolism pathways. FSAL offer a promising choice for food prevention and safety. KEY POINTS: • FSAL negatively affects the glycerolipid metabolism of B. cinerea • FSAL minimum inhibitory concentration against B. cinerea was 1.500 mg/mL • FSAL could be utilized as a new prevention strategy for gray mold in fruits.

Regulation of Heat Stress in Physcomitrium (Physcomitrella) patens Provides Novel Insight into the Functions of Plant RNase H1s

RNase H1s are associated with growth and development in both plants and animals, while the roles of RNase H1s in bryophytes have been rarely reported. Our previous data found that PpRNH1A, a member of the RNase H1 family, could regulate the development of Physcomitrium (Physcomitrella) patens by regulating the auxin. In this study, we further investigated the biological functions of PpRNH1A and found PpRNH1A may participate in response to heat stress by affecting the numbers and the mobilization of lipid droplets and regulating the expression of heat-related genes. The expression level of PpRNH1A was induced by heat stress (HS), and we found that the PpRNH1A overexpression plants (A-OE) were more sensitive to HS. At the same time, A-OE plants have a higher number of lipid droplets but with less mobility in cells. Consistent with the HS sensitivity phenotype in A-OE plants, transcriptomic analysis results indicated that PpRNH1A is involved in the regulation of expression of heat-related genes such as DNAJ and DNAJC. Taken together, these results provide novel insight into the functions of RNase H1s.