Full-length transcriptome of in Medicago sativa L. roots in response to drought stress

Identification of key genes for triacylglycerol biosynthesis and storage in herbaceous peony (Paeonia lactifolra Pall.) seeds based on full-length transcriptome

BACKGROUND

The herbaceous peony (Paeonia lactiflora Pall.) is extensively cultivated in China due to its root being used as a traditional Chinese medicine known as 'Radix Paeoniae Alba'. In recent years, it has been discovered that its seeds incorporate abundant unsaturated fatty acids, thereby presenting a potential new oilseed plant. Surprisingly, little is known about the full-length transcriptome sequencing of Paeonia lactiflora, limiting research into its gene function and molecular mechanisms.

RESULTS

A total of 484,931 Reads of Inserts (ROI) sequences and 1,455,771 full-Length non-chimeric reads (FLNC) sequences were obtained for CDS prediction, TF analysis, SSR analysis and lncRNA identification. In addition, gene function annotation and gene structure analysis were performed. A total of 4905 transcripts were related to lipid metabolism biosynthesis pathway, belonging to 28 enzymes. We use these data to identify 10 oleosin (OLE) and 5 diacylglycerol acyltransferase (DGAT) gene members after de-redundancy. The analysis of physicochemical properties and secondary structure showed them similarity in gene family respectively. The phylogenetic analysis showed that the distribution of OLE and DGAT family members was roughly the same as that of Arabidopsis. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed expression changes in different seed development stages, and showed a trend of increasing and then decreasing.

CONCLUSION

In summary, these results provide new insights into the molecular mechanism of triacylglycerol (TAG) biosynthesis and storage during the seedling stage in Paeonia lactiflora. It provides theoretical references for selecting and breeding oil varieties and understanding the functions of oil storage as well as lipid synthesis related genes in Paeonia lactiflora.

Research on drought stress in Medicago sativa L. from 1998 to 2023: a bibliometric analysis

Alfalfa (Medicago sativa L.) is one of the most important forage crops in the world. Drought is recognized as a major challenge limiting alfalfa production and threatening food security. Although some literature reviews have been conducted in this area, bibliometric reviews based on large amounts of published data are still lacking. In this paper, a bibliometric analysis of alfalfa drought stress from 1998-2023 was conducted using the Web of Science Core Collection database in order to assess global trends in alfalfa drought stress research and to provide new directions for future research. The results showed that the annual publication output maintained an increase in most years, with China and the United States contributing significantly to the field. Most of the journals published are specialized journals in botany, environmental science, soil science and crop science, as well as related agribusiness journals. "plant growth" and "yield" were the most frequently used keywords, reflecting the important purpose of research in this field. And two main research directions were identified: research on drought response mechanism of alfalfa and exploration of drought-resistant technology. In addition, physiological, biochemical, and molecular responses of drought tolerance and high yield in alfalfa, transgenics, and microbial fertilizer research have been hot research topics in recent years and may continue in the future. The ultimate goal of this paper is to provide a foundational reference for future research on alfalfa's drought resistance and yield optimization mechanisms, thereby enhancing the crop's application in agricultural production.

Transcriptome sequencing and metabolome analysis reveal the molecular mechanism of Salvia miltiorrhiza in response to drought stress

Salvia miltiorrhiza is commonly used as a Chinese herbal medicine to treat different cardiovascular and cerebrovascular illnesses due to its active ingredients. Environmental conditions, especially drought stress, can affect the yield and quality of S. miltiorrhiza. However, moderate drought stress could improve the quality of S. miltiorrhiza without significantly reducing the yield, and the mechanism of this initial drought resistance is still unclear. In our study, transcriptome and metabolome analyses of S. miltiorrhiza under different drought treatment groups (CK, A, B, and C groups) were conducted to reveal the basis for its drought tolerance. We discovered that the leaves of S. miltiorrhiza under different drought treatment groups had no obvious shrinkage, and the malondialdehyde (MDA) contents as well as superoxide dismutase (SOD) and peroxidase (POD) activities dramatically increased, indicating that our drought treatment methods were moderate, and the leaves of S. miltiorrhiza began to initiate drought resistance. The morphology of root tissue had no significant change under different drought treatment groups, and the contents of four tanshinones significantly enhanced. In all, 5213, 6611, and 5241 differentially expressed genes (DEGs) were shared in the A, B, and C groups compared with the CK group, respectively. The results of KEGG and co-expression analysis showed that the DEGs involved in plant-pathogen interactions, the MAPK signaling pathway, phenylpropanoid biosynthesis, flavonoid biosynthesis, and plant hormone signal transduction responded to drought stress and were strongly correlated with tanshinone biosynthesis. Furthermore, the results of metabolism analysis indicated that 67, 72, and 92 differentially accumulated metabolites (DAMs), including fumarate, ferulic acid, xanthohumol, and phytocassanes, which were primarily involved in phenylpropanoid biosynthesis, flavonoid biosynthesis, and diterpenoid biosynthesis pathways, were detected in these groups. These discoveries provide valuable information on the molecular mechanisms by which S. miltiorrhiza responds to drought stress and will facilitate the development of drought-resistant and high-quality S. miltiorrhiza production.

Full-length transcriptome sequencing provides new insights into the complexity of flavonoid biosynthesis in Glechoma longituba

Glechoma longituba has been frequently used in treating urolithiasis and cholelithiasis due to the presence of flavonoids, which are its major bioactive constituents. However, research on the molecular background of flavonoid biosynthesis in G. longituba is limited. In this study, we used single-molecule real-time combined with next-generation sequencing technologies to construct the complete transcriptome of G. longituba. We identified 404,648 non-redundant transcripts, including 249,697 coding sequences, 197,811 simple sequence repeats, 174,846 long noncoding RNA, and 176,554 coding RNA. Moreover, we functionally annotated 346,218 isoforms (85.56%) and identified 86,528 differentially expressed genes. We also identified 55 non-redundant full-length isoforms related to the flavonoid biosynthetic pathway. Pearson correlation analysis revealed that the expression levels of some key genes of the flavonoid biosynthesis pathway were significantly positively correlated with the flavonoid metabolites. Furthermore, we performed bioinformatics analysis (sequence and structural) of isoform_47029 (encoding flavanone 3-hydroxylase) and isoform_53692 (encoding flavonol synthase) to evaluate their potential biological functions. Finally, we validated gene expression levels of 12 flavonoid-related key enzyme genes using quantitative real-time PCR. Overall, this study provides full-length transcriptome information on G. longituba for the first time and valuable molecular resources for further research on the medicinal properties of this plant.