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.

De novo full-length transcriptome analysis of two ecotypes of Phragmites australis (swamp reed and dune reed) provides new insights into the transcriptomic complexity of dune reed and its long-term adaptation to desert environments.

BACKGROUND: The extremely harsh environment of the desert is changing dramatically every moment, and the rapid adaptive stress response in the short term requires enormous energy expenditure to mobilize widespread regulatory networks, which is all the more detrimental to the survival of the desert plants themselves. The dune reed, which has adapted to desert environments with complex and variable ecological factors, is an ideal type of plant for studying the molecular mechanisms by which Gramineae plants respond to combinatorial stress of the desert in their natural state. But so far, the data on the genetic resources of reeds is still scarce, therefore most of their research has focused on ecological and physiological studies. RESULTS: In this study, we obtained the first De novo non-redundant Full-Length Non-Chimeric (FLNC) transcriptome databases for swamp reeds (SR), dune reeds (DR) and the All of Phragmites australis (merged of iso-seq data from SR and DR), using PacBio Iso-Seq technology and combining tools such as Iso-Seq3 and Cogent. We then identified and described long non-coding RNAs (LncRNA), transcription factor (TF) and alternative splicing (AS) events in reeds based on a transcriptome database. Meanwhile, we have identified and developed for the first time a large number of candidates expressed sequence tag-SSR (EST-SSRs) markers in reeds based on UniTransModels. In addition, through differential gene expression analysis of wild-type and homogenous cultures, we found a large number of transcription factors that may be associated with desert stress tolerance in the dune reed, and revealed that members of the Lhc family have an important role in the long-term adaptation of dune reeds to desert environments. CONCLUSIONS: Our results provide a positive and usable genetic resource for Phragmites australis with a widespread adaptability and resistance, and provide a genetic database for subsequent reeds genome annotation and functional genomic studies.

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

Land colonization is a major event in plant evolution. Little is known about the evolutionary characteristics of lipids during this process. Here, we proved that Physcomitrella patens, a bryophyte that appeared in the early evolution of terrestrial plants, has short-term desiccation resistance. The maintenance of membrane integrity is related to its specific glycerolipid composition and key genes for lipid metabolism. We analyzed 414 types of lipid molecules, and found that phospholipids accounted for 61.7%, mainly PC and PI; glycolipids accounted for only 26.5%, with a special MGDG molecular map. The most abundant MDGD, that is, MGDG34:6, contained rare 15- and 19-carbon acyl chains; the level of neutral lipids was higher. This was consistent with the results observed by TEM, with fewer lamellae and obvious lipid droplets. Slight dehydration accumulated a large number of TAG molecules, and severe dehydration degraded phospholipids and caused membrane leakage, but PA and MGDG fluctuated less. The key genes of lipid metabolism, DGAT and PAP, were actively transcribed, suggesting that PA was one of the main DAG sources for TAG synthesis. This work proves that Physcomitrella patens adopts high-constitutive PC and PI similar to plant seeds, abundant TAG, and its own specific MGDG to resist extreme dehydration. This result provides a new insight into the lipid evolution of early terrestrial plants against unfavorable terrestrial environments.