Wenyu Liang’s research while affiliated with Ningxia University and other places

Licorice from Glycyrrhiza uralensis roots is used in foods and medicines. Although we are aware that licorice roots and leaves have distinct material compositions, the specific reasons for these differences remain unknown. Comparison of the metabolomes and transcriptomes between the leaves and roots revealed flavonoids and triterpenoid saponins were significantly different. Isoflavones were enriched in roots because of upregulation of genes encoding chalcone isomerase and flavone synthase, which are involved in isoflavone synthesis. Six triterpenoid saponins were significantly enriched only in the roots. The leaves did not accumulate glycyrrhetinic acid because of low expression levels of genes involved in its synthesis. A gene encoding a UDP glycosyltransferase, which likely catalyzes the key step in the transformation of glycyrrhetinic acid to glycyrrhizin, was screened. Our results provide information about the differences in flavonoid and triterpenoid synthesis between roots and leaves, and highlight targets for genetic engineering.

Prunus mongolica is an ecologically and economically important xerophytic tree native to Northwest China. Here, we report a high-quality, chromosome-level P. mongolica genome assembly integrating PacBio high-fidelity sequencing and Hi-C technology. The assembled genome was 233.17 Mb in size, with 98.89% assigned to eight pseudochromosomes. The genome had contig and scaffold N50s of 24.33 Mb and 26.54 Mb, respectively, a BUSCO completeness score of 98.76%, and CEGMA indicated that 98.47% of the assembled genome was reliably annotated. The genome contained a total of 88.54 Mb (37.97%) of repetitive sequences and 23,798 protein-coding genes. We found that P. mongolica experienced two whole-genome duplications, with the most recent event occurring ~3.57 million years ago. Phylogenetic and chromosome syntenic analyses revealed that P. mongolica was closely related to P. persica and P. dulcis. Furthermore, we identified a number of candidate genes involved in drought tolerance and fatty acid biosynthesis. These candidate genes are likely to prove useful in studies of drought tolerance and fatty acid biosynthesis in P. mongolica, and will provide important genetic resources for molecular breeding and improvement experiments in Prunus species. This high-quality reference genome will also accelerate the study of the adaptation of xerophytic plants to drought.

Lysine malonylation (Kmal) is an evolutionarily conserved post-translational modification (PTM) that has been demonstrated to be involved in cellular and organismal metabolism. However, the role that Kmal plays in response to drought stress of the terrestrial cyanobacteria N. flagelliforme is still unknown. In this study, we performed the first proteomic analysis of Kmal in N. flagelliforme under different drought stresses using LC-MS/MS. In total, 421 malonylated lysine residues were found in 236 different proteins. GO and KEGG enrichment analysis indicated that these malonylated proteins were highly enriched in several metabolic pathways, including carbon metabolism and photosynthesis. Decreased malonylation levels were found to hinder the reception and transmission of light energy and CO2 fixation, which led to a decrease in photosynthetic activity. Kmal was also shown to inhibit the flux of the TCA cycle and activate the gluconeogenesis pathway in response to drought stress. Furthermore, malonylated antioxidant enzymes and antioxidants were synergistically involved in reactive oxygen species (ROS) scavenging. Malonylation was involved in lipid degradation and amino acid biosynthesis as part of drought stress adaptation. This work represents the first comprehensive investigation of the role of malonylation in dehydrated N. flagelliforme, providing an important resource for understanding the drought tolerance mechanism of this organism.

Nostoc flagelliforme is a kind of terrestrial edible cyanobacteria with important ecological and economic value which has developed special mechanisms to adapt to drought conditions. However, the specific mechanism of lipidome changes in drought tolerance of N. flagelliforme has not been well understood. In this study, the ultra-high-performance liquid chromatography and mass spectrometry were employed to analyze the lipidome changes of N. flagelliforme under dehydration. A total of 853 lipid molecules were identified, of which 171 were significantly different from that of the control group. The digalactosyldiacylglycerol/monogalactosyldiacylglycerol (DGDG/MGDG) ratio was increased. The amount of wax ester (WE) was sharply decreased during drought stress, while Co (Q10) was accumulated. The levels of odd chain fatty acids (OCFAs) were increased under dehydration, positively responding to drought stress according to the energy metabolism state. In conclusion, the lipidomic data corroborated that oxidation, degradation, and biosynthesis of membrane lipids took place during lipid metabolism, which can respond to drought stress through the transformation of energy and substances. Besides, we constructed a lipid metabolic model demonstrating the regulatory mechanism of drought stress in N. flagelliforme. The present study provides insight into the defense strategies of cyanobacteria in lipid metabolic pathways.

Background Drought is an important abiotic stress that constrains the growth of many species. Despite extensive study in model organisms, the underlying mechanisms of drought tolerance in Nostoc flagelliforme remain elusive. Results We characterized the drought adaptation of N. flagelliforme by a combination of proteomics and qRT-PCR. A total of 351 differentially expressed proteins involved in drought stress adaptation were identified. It was found that the expression of several nutrient influx transporters was increased, including molybdate ABC transporter substrate binding protein (modA), sulfate ABC transporter substrate-binding protein (sbp) and nitrate ABC transporter (ntrB), while that of efflux transporters for toxic substances was also increased, including arsenic transporting ATPase (ArsA), potassium transporter (TrkA) and iron ABC transporter substrate-binding protein (VacB). Additionally, photosynthetic components were reduced while sugars built up during drought stress. Non-enzymatic antioxidants, orange carotenoid protein (OCP) homologs, cytochrome P450 (CYP450), proline (Pro) and ascorbic acid (AsA) were all altered during drought stress and may play important roles in scavenging reactive oxygen species (ROS). Conclusion In this study, N. flagelliforme may regulates its adaptation to drought stress through the changes of protein expression in photosynthesis, energy metabolism, transport, protein synthesis and degradation and antioxidation. Highlights • A total of 351 DEPs involved in adaptation to drought stress were identified. • Changes in the expression of six OCP homologs were found in response to drought stress. • Differential expression of transporters played an important role in drought stress adaptation. • Most PSII proteins were downregulated, while PSI proteins were unchanged in response to drought stress. • Sugar metabolism was upregulated in response to drought stress.

The high salt- and drought-tolerance of Lycium barbarum L. (goji berry) makes the plant suitable for cultivation in the arid and semi-arid regions of northwest China. However, monocropping of L. barbarum has caused severe issues, including increasing plant disease incidents and declining goji berry productivity. The negative impacts of L. barbarum monocropping on the soil health over time remain unclear. We investigated the temporal shifts in soil properties and microbial community diversity in the top (0–20 cm) and subsoils (20–40 cm) of L. barbarum fields across a 20-year age sequence and the adjacent control fields at two independent research sites in Ningxia, China. Our results show that L. barbarum monocropping leads to accumulation of total organic C, N, P, and available N stocks, but simultaneously caused secondary soil salinization and soil pH declination. The community α-diversity indices and the dissimilarities in community compositions of bacteria and fungi generally decline with the increase in stand age at both soil depths. Co-occurrence analysis found a decreased complexity of network structure with stand development, indicating that monocropping would profoundly disrupt the potential interactions among soil microbes. The phytopathogenic fungi Fusarium spp. progressively prevailed in soils of L. barbarum fields. The structural equation modeling further demonstrates that the variation in bacterial community composition directly explained the increase in the absolute abundance of Fusarium spp. The results infer an essential role of soil bacterial assemblages in the biocontrol of Fusarium wilt of L. barbarum under monocropping. Together, our results suggest that secondary soil salinization, loss of soil microbial diversity, and build-up of fungal phytopathogens, particularly in subsoils, are major threats to the soil health of L. barbarum field. An in-depth understanding of these threats to soil quality could help develop sustainable cropping management for L. barbarum.

Nostoc flagelliforme is a remarkable drought-resistant terrestrial cyanobacterium whose exopolysaccharides (EPS) have been found to exert important physiological and ecological functions, and the EPS are known to improve soil physicochemical properties. In this study, we used physiological and molecular methods to investigate the influences of three moisture loss levels on EPS production and the antioxidant system in N. flagelliforme. The aim was to reveal the EPS production mechanism involved in the gene differential expression and antioxidant system of N. flagelliforme in response to drought. Our results showed that EPS contents increased by 13% and 22% after 6-h and 48-h dehydration (6HAD and 48HAD) compared with 4-h rehydration (4HAR), respectively. The same trends were also detected for most EPS synthesis genes, especially glycosyltransferases. Furthermore, the intracellular reactive oxygen species (ROS) levels in N. flagelliforme were generally higher at 6HAD and 48HAD than at 4HAR. Superoxide dismutase (SOD) and peroxidase (POD) activities were restricted in N. flagelliforme under 6HAD and 48HAD compared with 4HAR, but the opposite result was found in catalase (CAT) activity. These results provide a new foundation for understanding the mechanism of EPS accumulation in N. flagelliforme in response to drought.

Terrestrial cyanobacteria, originated from aquatic cyanobacteria, exhibit a unique mechanism for drought adaptation during long-term evolution. To elucidate this diverse adaptive mechanism exhibited by terrestrial cyanobacteria from the post-translation modification aspect, we performed a global phosphoproteome analysis on the abundance of phosphoproteins in response to dehydration using Nostoc flagelliforme, a kind of terrestrial cyanobacteria having strong ecological adaptability to xeric environments. A total of 329 phosphopeptides from 271 phosphoproteins with 1168 phosphorylation sites were identified. Among these, 76 differentially expressed phosphorylated proteins (DEPPs) were identified for each dehydration treatment (30, 75, and 100% water loss), compared to control. The identified DEPPs were functionally categorized to be mainly involved in a two-component signaling pathway, photosynthesis, energy and carbohydrate metabolism, and an antioxidant system. We concluded that protein phosphorylation modifications related to the reactive oxygen species (ROS) signaling pathway might play an important role in coordinating enzyme activity involved in the antioxidant system in N. flagelliforme to adapt to dehydration stress. This study provides deep insights into the extensive modification of phosphorylation in terrestrial cyanobacteria using a phosphoproteomic approach, which may help to better understand the role of protein phosphorylation in key cellular mechanisms in terrestrial cyanobacteria in response to dehydration.

Nostoc flagelliforme is a type of terrestrial cyanobacteria that is distributed in arid or semi-arid steppes in China. To research the molecular mechanisms underlying the adaptation of N. flagelliforme to drought stress, the succinylated expression profile and changes in N. flagelliforme that resulted as a response to dehydration were analyzed by label-free proteomics. A total of 1149 succinylated sites, 1128 succinylated peptides, and 396 succinylated proteins were identified. Succinylated proteins were differentially involved in photosynthesis and energy metabolism, as well as in reactive oxygen species (ROS) scavenging. Motif-X analysis of succinylated sites determined a succinylation motif [KxxG]. N. flagelliforme adapts to dehydration by increasing glucose metabolism and pentose phosphate pathway flux, and decreasing photosynthetic rate, which some of the key proteins were succinylated. ROS scavenging was mainly involved in the regulation of the enzyme antioxidant defense system and non-enzymatic antioxidant defense system through succinylation modification, thus eliminating excessive ROS. Protein succinylation of N. flagelliforme may play an important regulatory role in response to dehydration. The results are foundational, as they can inform future research into the mechanisms involved in the succinylation regulation mechanism of N. flagelliforme in response to dehydration. Significance The global succinylation network involved in response to dehydration in N. flagelliforme has been established. We found that many succinylated proteins were involved in photosynthesis, glucose metabolism and antioxidation. The global survey of succinylated proteins and the changes of succinylated levels in response to dehydration provided effective information for the drought tolerance mechanism in N. flagelliforme.