Root rot destabilizes the Sanqi rhizosphere core fungal microbiome by reducing the negative connectivity of beneficial microbes.

The stability of microbial communities, especially among core taxa, is essential for supporting plant health. However, the impacts of disease infection on the stability of rhizosphere fungal core microbiome remain largely unexplored. In this study, we delved into the effects of root rot infestation on the community structure, function, network complexity, and stability of Sanqi fungal core microbiomes, employing amplicon sequencing combined with co-occurrence network and cohesion analyses. Our investigation revealed that root rot disease led to a decrease in the α-diversity but an increase in the ß-diversity of the Sanqi fungal core microbiomes in the rhizosphere. Notably, Ilyonectria, Plectosphaerella, and Fusarium emerged as indicator species in the rhizosphere core microbiome of root rot-infected Sanqi plants, while Mortierella predominated as the dominant biomarker taxa in healthy soils. Additionally, root rot diminished the complexity and modularity of the rhizosphere networks by reducing the metrics associated with nodes, edges, degrees, and modularity. Furthermore, root rot resulted in a reduction in the proportion of negative connections in the network and the negative/positive cohesion of the entire core fungal microbiome. Particularly noteworthy was the observation that root rot infection destabilized the rhizosphere core fungal microbiome by weakening the negative connectivity associated with beneficial agents. Collectively, these results highlight the significance of the negative connectivity of beneficial agents in ensuring the stability of core microbial community.IMPORTANCERoot rot disease has been reported as the most devastating disease in the production process of artificial cultivated Sanqi ginseng, which seriously threatens the Sanqi industry. This study provides valuable insights into how root rot influences microbial relationships within the community. These findings open up opportunities for disease prevention and the promotion of plant health by regulating microbial interactions. In summary, the research sheds light on the ecological consequences of root rot on rhizosphere fungal microbiomes and offers potential strategies for managing soil-borne diseases and enhancing plant health.

The loss of microbial autotoxin degradation functions is associated with the decline of beneficial bacterial agents induced by phenolic acids.

Continuous cultivation of medicinal plants can disrupt the rhizosphere's microbial community. There is still a need to know about the beneficial bacterial community, their putative drivers, and the potential functions they may have. This study used different growth years of Sanqi ginseng (Panax notoginseng) with root rot to look at the beneficial microbial community structure, the function of microbial carbon source utilization, and the function of rhizosphere soil metabolism. The beneficial bacterial community changed and the relative abundance of beneficial agents was suppressed significantly with the successive Sanqi ginseng plantings. The carbon source utilization capacity and diversity increased significantly, whereas three autotoxin degradation-related pathways (biosynthesis of other secondary metabolites, metabolism of terpenoids and polyketides, and xenobiotics biodegradation and metabolism) were downregulated considerably with planting year extended. The changes in the beneficial agents were driven by the shifts in phenolic acid profiles, and the decline of beneficial microbes led to the loss of microbial autotoxin degradation functions. Overall, these results provide insight into beneficial microbes, microbial functions, phenolic acids, and their interactions, and these findings are essential for maintaining healthy and sustainable cultivation of Sanqi ginseng. IMPORTANCE Sanqi ginseng is a valuable perennial Chinese herb with various benefits for human health. However, continuous cultivation causes a high incidence of root rot disease, which leads to decreased yield and serious economic losses and ultimately impedes the sustainable development of Chinese medicine production. The significance of this study is to reveal the pattern of changes in beneficial bacteria and their related functions in root rot diseased rhizosphere with the successive planting years of Sanqi ginseng. This study found that the decline of beneficial bacterial agents mediated by phenolic acid profiles appears to be associated with the loss of microbial autotoxin degradation functions. This result may have new implications for deciphering the causes of Sanqi ginseng's continuous cropping obstacles.

[Qualitative and quantitative study of flavonoids in Notoginseng Radix et Rhizoma based on UPLC-Q-TOF-MS and HPLC-DAD].

The flavonoids in Panax notoginseng were qualitatively analyzed by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry(UPLC-Q-TOF-MS), and the content of three main flavonoids in P. notoginseng of different specifications and grades collected from different habitats was determined by HPLC-DAD. Flavonoids and anthocyanins were analyzed by UPLC-Q-TOF-MS/MS in the positive and negative ion modes, respectively. Twelve flavonoid glycosides and one anthocyanin glycoside in P. notoginseng were identified, but no flavonoid aglycones were detected. Among them, 12 compounds were identified in the underground part of P. notoginseng for the first time and eight compounds were first reported in this plant. Moreover, six and four compounds were identified in the Panax genus and the Araliaceae family for the first time, respectively. A method for simultaneous determination of three flavonoids in P. notoginseng was established by HPLC-DAD. The content of flavonoids in 721 P. notoginseng samples of 124 specifications and grades collected from 20 different habitats was simultaneously determined. Among three flavonoids determined, the content of quercetin-3-O-(2″-ß-D-xylosyl)-ß-D-galactoside was the highest with the average content in the tested samples of 161.0 µg·g~(-1). The content of compounds quercetin-3-O-hexosyl-hexoside and kaempferol-3-O-pentosyl-hexoside was relatively low, with the average content of 18.5 µg·g~(-1)(calculated as quercetin-3-O-sophoroside) and 49.4 µg·g~(-1)(calculated as kaempferol-3-O-sangbu diglycoside). There were significant differences in flavonoids content of samples from different production area. The content of flavonoids in spring P. notoginseng was significantly lower than that in winter P. notoginseng when the other influencing factors such as production areas, germplasm resources, and cultivation conditions were fixed. As for P. notoginseng of different specifications, the flavonoid content in the part connecting the taproot and the aboveground stem was significantly higher than that in other parts. The results of large-scale data showed that the flavonoid content gradually increased with the increase in the number of heads. There were significant differences between the flavonoid content in most specifications and grades, especially the 20-head P. notoginseng and countless head P. notoginseng, whose content was significantly lower and significantly higher than that of other specifications and grades, respectively. This study provides a scientific basis for the study of the effective components and quality control of P. notoginseng from the perspective of flavonoids.

Core rhizosphere microbiome of Panax notoginseng and its associations with belowground biomass and saponin contents.

The core rhizosphere microbiome is critical for plant fitness. However, its contribution to the belowground biomass and saponin contents of Panax notoginseng remains unclear. High-throughput sequencing of amplicon and metagenome was performed to obtain the microbiome profiles and functional traits in P. notoginseng rhizosphere across a large spatial scale. We obtained 639 bacterial and 310 fungal core OTUs, which were mainly affected by soil pH and organic matter (OM). The core taxa were grouped into four ecological clusters (i.e. high pH, low pH, high OM and low OM) for sharing similar habitat preferences. Furthermore, structural equation modelling (SEM) and correlation analyses revealed that the diversity and composition of core microbiomes, as well as the metagenome-derived microbial functions, were related to belowground biomass and saponin contents. Key microbial genera related to the two plant indicators were also identified. In short, this study explored the main driving environmental factors of core microbiomes in the P. notoginseng rhizosphere and revealed that the core microbiomes and microbial functions potentially contributed to the belowground biomass and saponin contents of the plant. This work may enhance our understanding of interactions between microbes and perennial plants and improve our ability to manage root microbiota for the sustainable production of herbal medicine.

Biochar increases Panax notoginseng's survival under continuous cropping by improving soil properties and microbial diversity.

Replant problem is widespread in agricultural production and causes serious economic losses, which has limited sustainable cultivation of Panax notoginseng (PN), a well-known medicinal plant in Asia. Here we conducted a field experiment to investigate the effectiveness and possible mechanisms of biochar to improve its survival under continuous cropping. Biochar from tobacco stems was applied at 4 rates of 9.0, 12, 15, and 18 t/ha to a soil where PN has been continuously cultivated for 10 years. After 18 months, soil properties, 5 allelochemicals, including p-hydroxybenzoic acid, vanillic acid, syringic acid, p-coumaric acid, and ferulic acid, key pathogen Fusarium oxysporum, microbial community, and PN survival rate were investigated. Our results show that 10 years' continuous PN cropping led to soil acidification, accumulation of NH4+-N and F. oxysporum, and low PN survival rate. However, biochar increased its survival rate from 6.0% in the control to 69.5% under 15 t/ha treatment. Moreover, soil pH, available P and K, organic matter content, and microbial diversity were increased while NH4+-N and allelochemicals vanillic acid and syringic acid contents were decreased under biochar treatment (P<0.05). Soil available K increased from 177 to 283 mg·kg-1 while NH4+-N decreased from 6.73 to 4.79 mg·kg-1 under 15 t/ha treatment. Further, soil pH, available P and K, and microbial diversity (bacteria and fungi) were positively correlated with PN survival rate, however, NH4+-N content was negatively correlated (P<0.05). Our study indicates that biochar effectively increased the survival rate of Panax notoginseng under continuous cropping by improving soil properties and microbial diversity.

Temporal Dynamics of Rhizosphere Communities Across the Life Cycle of Panax notoginseng.

Rhizosphere microbiome promotes plant growth; however, the succession of rhizosphere microbial community during the growth stages of perennial medicinal plant Panax notoginseng (P. notoginseng) is still unclear. Here, amplicon sequencing was performed to assess the succession characteristics of rhizosphere microbiomes during developmental stages. Results showed that bacterial and fungal communities were mainly shaped by the development stages. The microbial α-diversities first increased and then decreased with plant growth and the variation in microbial composition was active at the 3-year root growth (3YR) stage. The variation trend of cross-domain co-occurrence network complexity was similar to that of α-diversities. Cross-domain nodes decreased at the 3YR stage and fungal nodes increased at the 3YR stage. This study provided a detailed and systematic survey of rhizosphere microbiomes during the growth stages of P. notoginseng. The findings revealed that the development stages of P. notoginseng drove the temporal dynamics of rhizosphere communities. This study helps in harnessing the power of microbiomes to evaluate herbal medicine growth and provides valuable information to guide the microbial breeding of medical plants.

Evidence for saponin diversity-mycobiome links and conservatism of plant-fungi interaction patterns across Holarctic disjunct Panax species.

Although interplays between plant and coevolved microorganisms are believed to drive landscape formation and ecosystem services, the relationships between the mycobiome and phytochemical evolution and the evolutionary characteristics of plant-mycobiome interaction patterns are still unclear. The present study explored fungal communities from 405 multiniche samples of three Holarctic disjunct Panax species. The overall mycobiomes showed compartment-dominated variations and dynamic universality. Neutral models were fitted for each compartment at the Panax genus (I) and species (II) levels to infer the community assembly mechanism and identify fungal subgroups potentially representing different plant-fungi interaction results, i.e., the potentially selected, opposed, and neutral taxa. Selection contributed more to the endosphere than to external compartments. The nonneutral taxa showed significant phylogenetic clustering. In Model I, the opposed subgroups could best reflect Panax saponin diversities (r = 0.69), and genera with highly positive correlations to specific saponins were identified using machine learning. Although mycobiomes in the three species differed significantly, subgroups in Model II were phylogenetically clustered based on potential interaction type rather than plant species, indicating potentially conservative plant-fungi interactions. In summary, the finding of strong links between invaders and saponin diversity can help explore the underlying mechanisms of saponin biosynthesis evolution from microbial insights, which is important to understanding the formation of the current landscape. The potential conservatism of plant-fungi interaction patterns suggests that the related genetic modules and selection pressures were convergent across Panax species, advancing our understanding of plant interplay with biotic environments.

[Effects of natural organic soil amendments on quality of Panax notoginseng].

The effects of four natural organic soil amendments on the quality and pesticide residues of Panax notoginseng were investigated through field experiments and the suitable dosage ratio of each soil amendment was selected to provide a new idea for the pollution-free cultivation of P. notoginseng. The four natural organic soil amendments used in this study were Jishibao, Jihuo, Fudujing, and omnipotent nutrients, which were produced by mixed fermentation of aboveground parts of different plants, biological waste residue, and biochar. During the experiments, only four soil amendments were applied to P. notoginseng instead of any pesticides and fertilizers. The experiment was designed as four factors and three levels. There were three dosage gradients(low, medium, and high) for Jishibao(A), Jihuo(B), Fudujing(C), and omnipotent nutrients(D). When the dosage of one soil amendment changed, the do-sage of the other soil amendments remained medium. There were 10 groups in addition to the soil amendment-free group as control(CK). The results showed that the four soil amendments could significantly improve the growth environment of P. notoginseng and increase the seedling survival rate and saponin content of P. notoginseng. The seedling survival rates of the treatment groups increased by 8.24%-30.05% as compared with the control group. Furthermore, the content of pesticide residues in P. notoginseng was too low to be detected, and that of heavy metals in P. notoginseng was far lower than the specified content in the Chinese Pharmacopoeia(2020). The optimal effect was achieved at medium dosage for all the soil amendments with the highest content of saponins, high seedling survival rate, and significantly reduced heavy metals, such as lead, cadmium, arsenic, and mercury.

Dispersal Limitation Plays Stronger Role in the Community Assembly of Fungi Relative to Bacteria in Rhizosphere Across the Arable Area of Medicinal Plant.

Understanding the ecological patterns of rhizosphere microbial communities is critical for propelling sustainable agriculture and managing ecosystem functions by exploiting microorganisms. However, this knowledge is still unclear, especially under host-associated large-scale and regarding the comparison between bacteria and fungi. We examined community assembly processes and community characters including environmental thresholds and co-occurrence patterns across the cultivatable area of Panax notoginseng for bacteria and fungi. Both are vital members of the rhizosphere but differ considerably in their life history and dispersal potentiality. Edaphic factors drove the parallel variations of bacterial and fungal communities. Although bacterial and fungal communities exhibited similar biogeographic patterns, the assembly of fungi was more driven by dispersal limitation than selection compared with bacteria. This finding supported the 'size-dispersal' hypothesis. pH and total nitrogen respectively mediated the relative importance of deterministic and stochastic processes in shaping bacterial and fungal communities. In addition, fungal communities exhibited potentially broader environmental thresholds and more modular co-occurrence patterns than bacteria (bacteria: 0.67; fungi: 0.78). These results emphasized the importance of dispersal limitation in structuring rhizosphere microbiota and shaping community features of ecologically distinct microorganisms. This study provides insights into the improved prediction and management of the key functions of rhizosphere microbiota.

Endophytes isolated from Panax notoginseng converted ginsenosides.

Endophytes may participate in the conversion of metabolites within medicinal plants, influencing the efficacy of host. However, the distribution of endophytes within medicinal plants P. notoginseng and how it contributes to the conversion of saponins are not well understood. Here, we determined the distribution of saponins and endophytes within P. notoginseng compartments and further confirm the saponin conversion by endophytes. We found metabolites showed compartment specificity within P. notoginseng. Potential saponin biomarkers, such as Rb1, Rg1, Re, Rc and Rd, were obtained. Endophytic diversity, composition and co-occurrence networks also showed compartment specificity, and bacterial alpha diversity values were highest in root compartment, consistently decreased in the stem and leaf compartments, whereas those of fungi showed the opposite trend. Potential bacterial biomarkers, such as Rhizobium, Bacillus, Pseudomonas, Enterobacter, Klebsiella, Pantoea and fungal biomarkers Phoma, Epicoccum, Xylariales, were also obtained. Endophytes related to saponin contents were found by Spearman correlation analysis, and further verification experiments showed that Enterobacter chengduensis could convert ginsenoside Rg1 to F1 at a rate of 13.24%; Trichoderma koningii could convert ginsenoside Rb1 to Rd at a rate of 40.00% and to Rg3 at a rate of 32.31%; Penicillium chermesinum could convert ginsenoside Rb1 to Rd at a rate of 74.24%.

Genomic and Transcriptomic Analysis Provide Insights Into Root Rot Resistance in Panax notoginseng.

Panax notoginseng (Panax notoginseng (Burk.) F.H. Chen), a plant of high medicinal value, is severely affected by root rot during cultivation. Here, we generated a reference genome of P. notoginseng, with a contig N50 size of 241.268 kb, and identified 66 disease-resistance genes (R-genes) as candidate genes for breeding disease-resistant varieties. We then investigated the molecular mechanism underlying the responses of resistant and susceptible P. notoginseng genotypes to Fusarium oxysporum infection at six time points by RNA-seq. Functional analysis of the genes differentially expressed between the two genotypes indicated that genes involved in the defense response biological process like hormone transduction and plant-pathogen interaction are continuously and highly expressed in resistant genotype during infection. Moreover, salicylic acid and jasmonic acid levels gradually increased during infection in the resistant genotype. Coexpression analysis showed that PnWRKY22 acts as a hub gene in the defense response of the resistant genotype. Finally, transiently overexpressing PnWRKY22 increased salicylic acid levels in P. notoginseng leaves. Our findings provide a theoretical basis for studying root rot resistance in P. notoginseng.

Metabolomes and transcriptomes revealed the saponin distribution in root tissues of Panax quinquefolius and Panax notoginseng.

BACKGROUND: Panax quinquefolius and Panax notoginseng are widely used and well known for their pharmacological effects. As main pharmacological components, saponins have different distribution patterns in the root tissues of Panax plants. METHODS: In this study, the representative ginsenosides were detected and quantified by desorption electrospray ionization mass spectrometry and high-performance liquid chromatography analysis to demonstrate saponin distribution in the root tissues of P. quinquefolius and P. notoginseng, and saponin metabolite profiles were analyzed by metabolomes to obtain the biomarkers of different root tissues. Finally, the transcriptome analysis was performed to demonstrate the molecular mechanisms of saponin distribution by gene profiles. RESULTS: There was saponin distribution in the root tissues differed between P. quinquefolius and P. notoginseng. Eight-eight and 24 potential biomarkers were detected by metabolome analysis, and a total of 340 and 122 transcripts involved in saponin synthesis that were positively correlated with the saponin contents (R > 0.6, P < 0.05) in the root tissues of P. quinquefolius and P. notoginseng, respectively. Among them, GDPS1, CYP51, CYP64, and UGT11 were significantly correlated with the contents of Rg1, Re, Rc, Rb2, and Rd in P. quinquefolius. UGT255 was markedly related to the content of R1; CYP74, CYP89, CYP100, CYP103, CYP109, and UGT190 were markedly correlated with the Rd content in P. notoginseng. CONCLUSIONS: These results provided the visual and quantitative profiles of and confirmed the pivotal transcripts of CYPs and UGTs regulating the saponin distribution in the root tissues of P. quinquefolius and P. notoginseng.

SMRT- and Illumina-based RNA-seq analyses unveil the ginsinoside biosynthesis and transcriptomic complexity in Panax notoginseng.

Panax notoginseng is one of the most widely used traditional Chinese herbs with particularly valued roots. Triterpenoid saponins are mainly specialized secondary metabolites, which medically act as bioactive components. Knowledge of the ginsenoside biosynthesis in P. notoginseng, which is of great importance in the industrial biosynthesis and genetic breeding program, remains largely undetermined. Here we combined single molecular real time (SMRT) and Second-Generation Sequencing (SGS) technologies to generate a widespread transcriptome atlas of P. notoginseng. We mapped 2,383 full-length non-chimeric (FLNC) reads to adjacently annotated genes, corrected 1,925 mis-annotated genes and merged into 927 new genes. We identified 8,111 novel transcript isoforms that have improved the annotation of the current genome assembly, of which we found 2,664 novel lncRNAs. We characterized more alternative splicing (AS) events from SMRT reads (20,015 AS in 6,324 genes) than Illumina reads (18,498 AS in 9,550 genes), which contained a number of AS events associated with the ginsenoside biosynthesis. The comprehensive transcriptome landscape reveals that the ginsenoside biosynthesis predominantly occurs in flowers compared to leaves and roots, substantiated by levels of gene expression, which is supported by tissue-specific abundance of isoforms in flowers compared to roots and rhizomes. Comparative metabolic analyses further show that a total of 17 characteristic ginsenosides increasingly accumulated, and roots contained the most ginsenosides with variable contents, which are extraordinarily abundant in roots of the three-year old plants. We observed that roots were rich in protopanaxatriol- and protopanaxadiol-type saponins, whereas protopanaxadiol-type saponins predominated in aerial parts (leaves, stems and flowers). The obtained results will greatly enhance our understanding about the ginsenoside biosynthetic machinery in the genus Panax.

Composition and function of rhizosphere microbiome of Panax notoginseng with discrepant yields.

BACKGROUND: Panax notoginseng is a highly valuable medicinal plant. Reduced P. notoginseng yield is a common and serious problem that arises in a continuous cropping system. Variation in the composition and function of soil microbial community is considered the primary cause of yield reduction. METHODS: This study used shotgun metagenomic sequencing approaches to describe the taxonomic and functional features of P. notoginseng rhizosphere microbiome and screen microbial taxa and functional traits related to yields. RESULTS: At the family and genus level, a total of 43 families and 45 genera (relative abundance > 0.1%) were obtained, and the correlation with the yield of P. notoginseng was further analyzed. Nitrosomonadaceae, Xanthomonadaceae, Mycobacterium and Arthrobacter that were enriched in soils with higher yields were positively correlated with P. notoginseng yields, thereby suggesting that they might increase yields. Negative correlation coefficients indicated that Xanthobacteraceae, Caulobacteraceae, Oxalobacteraceae, Chitinophagaceae, Sphingomonas, Hyphomicrobium, Variovorax and Phenylobacterium might be detrimental to P. notoginseng growth. A total of 85 functional traits were significantly (P < 0.05) correlated with P. notoginseng yields. Functional traits, likely steroid biosynthesis and MAPK signaling pathway were positively correlated with P. notoginseng yields. In contrast, functional traits, such as bacterial secretion system, ABC transporters, metabolism of xenobiotics by cytochrome P450 and drug metabolism-cytochrome P450, were negatively associated with yields. CONCLUSIONS: This study describes an overview of the rhizosphere microbiome of P. notoginseng with discrepant yields and identifies the taxa and functional traits related to yields. Our results provide valuable information to guide the isolation and culture of potentially beneficial microorganisms and to utilize the power of the microbiome to increase plant yields in a continuous cropping system.

Diversity and composition of bacterial endophytes among plant parts of Panax notoginseng.

BACKGROUND: Bacterial endophytes are widespread inhabitants inside plant tissues that play crucial roles in plant growth and biotransformation. This study aimed to offer information for the exploitation of endophytes by analyzing the bacterial endophytes in different parts of Panax notoginseng. METHODS: We used high-throughput sequencing methods to analyze the diversity and composition of bacterial endophytes from different parts of P. notoginseng. RESULTS: A total of 174,761 classified sequences were obtained from the analysis of 16S ribosomal RNA in different parts of P. notoginseng. Its fibril displayed the highest diversity of bacterial endophytes. Principal coordinate analysis revealed that the compositions of the bacterial endophytes from aboveground parts (flower, leaf, and stem) differed from that of underground parts (root and fibril). The abundances of Conexibacter, Gemmatimonas, Holophaga, Luteolibacter, Methylophilus, Prosthecobacter, and Solirubrobacter were significantly higher in the aboveground parts than in the underground parts, whereas the abundances of Bradyrhizobium, Novosphingobium, Phenylobacterium, Sphingobium, and Steroidobacter were markedly lower in the aboveground parts. CONCLUSIONS: Our results elucidated the comprehensive diversity and composition profiles of bacterial endophytes in different parts of 3-year-old P. notoginseng. Our data offered pivotal information to clarify the role of endophytes in the production of P. notoginseng and its important metabolites.

Integrated Chemical and Transcriptomic Analysis Reveals the Distribution of Protopanaxadiol- and Protopanaxatriol-Type Saponins in Panax notoginseng.

Panax notoginseng is famous for its important therapeutic effects and commonly used worldwide. The active ingredients saponins have distinct contents in different tissues of P. notoginseng, and they may be related to the expression of key genes in the synthesis pathway. In our study, high-performance liquid chromatography results indicated that the contents of protopanaxadiol-(Rb1, Rc, Rb2, and Rd) and protopanaxatriol-type (R1, Rg1, and Re) saponins in below ground tissues were higher than those in above ground tissues. Clustering dendrogram and PCA analysis suggested that the below and above ground tissues were clustered into two separate groups. A total of 482 and 882 unigenes were shared in the below and above ground tissues, respectively. A total of 75 distinct expressions of CYPs transcripts (RPKM ≥ 10) were detected. Of these transcripts, 38 and 37 were highly expressed in the below ground and above ground tissues, respectively. RT-qPCR analysis showed that CYP716A47 gene was abundantly expressed in the above ground tissues, especially in the flower, whose expression was 31.5-fold higher than that in the root. CYP716A53v2 gene was predominantly expressed in the below ground tissues, especially in the rhizome, whose expression was 20.1-fold higher than that in the flower. Pearson's analysis revealed that the CYP716A47 expression was significantly correlated with the contents of ginsenoside Rc and Rb2. The CYP716A53v2 expression was associated with the saponin contents of protopanaxadiol-type (Rb1 and Rd) and protopanaxatriol-type (R1, Rg1, and Re). Results indicated that the expression patterns of CYP716A47 and CYP716A53v2 were correlated with the distribution of protopanaxadiol-type and protopanaxatriol-type saponins in P. notoginseng. This study identified the pivotal genes regulating saponin distribution and provided valuable information for further research on the mechanisms of saponin synthesis, transportation, and accumulation.

[DNA marker-assisted selection of medicinal plants (â ) .Breeding research of disease-resistant cultivars of Panax notoginseng].

DNA marker-assisted selection of medicinal plants is based on the DNA polymorphism, selects the DNA sequences related to the phenotypes such as high yields, superior quality, stress-resistance and so on according to the technologies of molecular hybridization, polymerase chain reaction and high-throughput sequencing, and assists the breeding of new cultivars. This study bred the first disease-resistant cultivar of notoginseng "Miaoxiang Kangqi 1" using the technology of DNA marker-assisted selection of medicinal plants and systematic breeding. The disease-resistant cultivar of notoginseng contained 12 special SNPs based on the analysis of Restriction-site Associated DNA Sequencing (RAD-Seq). Among the SNP (record_519688) was related to the root rot-resistant characteristics, which indicated this SNP could serve as genetic markers of disease-resistant cultivars and assist the systematic breeding. Compared to the conventional cultivated cultivars, the incidence rate of root-rot and rust-rot in notoginseng seedlings decreased by 83.6% and 71.8%, respectively. The incidence rate of root-rot respectively declined by 43.6% and 62.9% in notoginseng cultivation for 2 and 3 years compared with those of the conventional cultivated cultivars. Additionally, the potential disease-resistant groups were screened based on the relative SNP, and this model enlarged the target groups and advanced the breeding efficiency. DNA marker-assisted selection of medicinal plants accelerated the breeding and promotion of new cultivars, and guaranteed the healthy development of Chinese medicinal materials industry.

[DNA marker-assisted selection of medicinal plants (â ¢)Evaluation of disease resistance of "Miaoxiang Kangqi 1" --a new cultivar of Panax notoginseng].

DNA marked-assisted selection of medicinal plants accelerated the breeding and promotion of new cultivars, and guaranteed the healthy development of Chinese medicinal materials industry. The first disease-resistant cultivar of notoginseng, namely "Miaoxiang Kangqi 1", served as the object of study. We evaluated the Kangqi's resistance of seeds, seedlings and root against the pathological bacteria (Fusarum oxysporum) of root rot. Compared to the traditional cultivars, the disease index of notoginseng seeds declined by 52.0% after inoculation for seven days; the death rate of seedlings and disease index of root respectively decreased by 72.1% and 62.4% after inoculation for 25 days. Additionally, the growth inhibition ratio of notoginseng seeds and seedlings declined after inoculation. The seeds, seedlings and roots of "Miaoxiang Kangqi 1" showed significantly resistant to root rot. The evaluation of disease-resistance of Kangqi provided the basis for the popularization of new cultivar and guaranteed the favoring conduct of notoginseng pollution-free cultivation.

Stability-increasing effects of anthocyanin glycosyl acylation.

This review comprehensively summarizes the existing knowledge regarding the chemical implications of anthocyanin glycosyl acylation, the effects of acylation on the stability of acylated anthocyanins and the corresponding mechanisms. Anthocyanin glycosyl acylation commonly refers to the phenomenon in which the hydroxyl groups of anthocyanin glycosyls are esterified by aliphatic or aromatic acids, which is synthetically represented by the acylation sites as well as the types and numbers of acyl groups. Generally, glycosyl acylation increases the in vitro and in vivo chemical stability of acylated anthocyanins, and the mechanisms primarily involve physicochemical, stereochemical, photochemical, biochemical or environmental aspects under specific conditions. Additionally, the acylation sites as well as the types and numbers of acyl groups influence the stability of acylated anthocyanins to different degrees. This review could provide insight into the optimization of the stability of anthocyanins as well as the application of suitable anthocyanins in food, pharmaceutical and cosmetic industries.

Unveiling of Dominant Fungal Pathogens Associated With Rusty Root Rot of Panax notoginseng Based on Multiple Methods.

Root rot is an important disease hampering the sustainable cultivation of Panax notoginseng. Culture-dependent and independent techniques were used to elucidate the dominant fungal pathogen of rusty root rot of P. notoginseng. Based on Illumina sequencing profiles for fungi using ITS primers, five phyla-namely Ascomycota, Basidiomycota, Glomeromycota, Zygomycota, and Chytridiomycota-were identified, and the analyses showed that the Ascomycota was the dominant phylum (∼50 to 97%), especially in the symptomatic samples. Out of 226 total genera identified, seven genera had over 1% average abundance, including Ilyonectria, Fusarium, Tetracladium, Cladosporium, Rhizophagus, Alternaria, and Perisporiopsis. However, only Ilyonectria was the predominant genera in the symptomatic samples (∼76 to 80%), while the others, including Fusarium, had higher abundances in asymptomatic samples. Based on in vitro and in vivo pathogenicity, the isolate G3B was demonstrated to be the pathogen causing rusty root rot of P. notoginseng, and it was identified as Ilyonectria mors-panacis. Based on primers F2-R2 targeting the His3 gene of Ilyonectria, real-time quantitative PCR (qPCR) was performed as an additional proof confirming that I. mors-panacis was the dominant pathogen in the symptomatic samples during the years of the study (2014-2015).