First Report of Erysiphe astragali Causing Powdery Mildew on Astragalus mongholicus in China.

Astragalus mongholicus Bge. [A. membranaceus Bge. var. mongholicus (Bge.) Hsiao] is a highly valuable perennial medicinal plant mainly distributed in China, whose dry roots are known as Huangqi in traditional Chinese medicine for reinforcing vital energy, strengthening superficial resistance, and promoting tissue regeneration (Lin et al. 2000). A. mongholicus roots of high quality are produced in Northwest and North China. Since July 2021, powdery mildew outbreaks happened annually on the leaves of A. mongholicus in a plantation (123° 56' 40'' E, 47° 22' 20'' N) in Qiqihar city, Heilongjiang Province, China. Disease incidence reached 100% by October (Fig. 1A-C), causing severe impairment of growth. Powdery mildew spots of circular or irregular shapes emerged on upper surface of leaf, resulting in plentiful lesion specks. Dense white hyphae appeared chaotically intertwined. Hyphae were hyaline and highly flexuous, 5.3 - 10.7 µm in diameter (n = 20). Chasmothecia were globose or slightly ovoid-shaped and turned dark brown when matured. Chasmothecia (diameter: 135.2 - 222.9 µm, n = 20) existed abundantly on the diseased leaves in the fields. Conidiophores were 89.0 - 129.9 µm in length (n = 20) and composed of one cylindrical, straight foot cell, followed by two cells and one to three conidia. Conidia were slim ellipsoid-shaped, occasionally ovoid-shaped, measuring 14.6 - 24.7 µm by 6.4 to10.4 µm, length/width ratio was 1.8 - 3.0 (n = 30). Hyphal appressoria were nipple-shaped and appeared in singular, occasionally in pairs. Unbranched germ tube emerged reaching out of the germinating conidia while forming an acute angle with the long axis. Comprehensively, the pathogen exhibited micro-morphology of the genus Erysiphe. For molecular identification, pathogen was carefully scraped off diseased leaves for DNA extraction. We used the DNA samples of three biological replicates for the sequencing of the ITS rDNA fragment (primers by (White et al. 1990). All the samples resulted in an identical ITS sequence (deposited in GenBank as OQ390098.1). It displayed 99.83% identity with OP806835.1 of an E. astragali voucher collected in Iran (Fig. 1D-M, O). Hence, our pathogen was identified as an E. astragali stain. Additionally, we amplified the Mcm7 sequence (using primers by (Ellingham et al. 2019), deposited as OQ397582.1). We propagated 40-day-old A. mongholicus plants via germinating seeds in pot soil and performed pathogenicity tests. Firstly, we incubated detached healthy leaves of propagated plants with severely symptomatic leaves collected from the fields in petri dishes under saturated moisture content and room temperature. Powdery mildew symptoms emerged on each healthy leaf (n = 5) after two weeks. Further, we infected healthy plants (n = 5) by gently pressing and rubbing symptomatic leaves on each healthy leaf, and kept them in a greenhouse (24 ℃, 80% humidity, 16/8-hour light/dark cycle). After a month, symptoms emerged on a number of leaves of each infected plant. We performed micromorphology observation (Fig. 1N-P) and ITS sequencing to confirm that the results fulfilled Koch's postulates. Powdery mildew caused by E. astragali on A. strictus in Tibet (Wang and Jiang 2023) and on A. scaberrimus in Inner Mongolia (Sun et al. 2023) have been reported. Here we report powdery mildew caused by E. astragali on Astragalus mongholicus for the first time. These Astragalus spp. are all acknowledged to have medicinal values in China but their usages are quite different.

[Advances in research and application of Trichoderma for inducing resistance against root rot diseases in root and rhizome of Chinese medicinal materials].

Root rot is a microbial disease that is difficult to control and can result in serious losses in the planting of most Chinese medicinal materials. As high as 87.6% of roots or rhizomes of Chinese medicinal materials are susceptible to root rot, which seriously affects the cultivation development of Chinese medicinal materials. Trichoderma fungi, possessing biological control functions, can induce plants to improve their resistance to microbial diseases, promote plant growth, and effectively reduce the losses caused by various microbial diseases on cultivation. At present, Trichoderma is rarely used in the cultivation of Chinese medicinal materials, so it has great application potential for the prevention and control of root rot diseases in farmed Chinese medicinal materials. Based on the above situation, after comparison and discussion, it is believed that compared with chemical control and physical control, biological control of root rot diseases of Chinese medicinal materials is more efficient and meets the development needs of Chinese medicinal materials ecological planting in China. This paper reviewed the progress in the research and application of Trichoderma in the control of root rot diseases in the root and rhizome of farmed Chinese medicinal materials in the past 10 years and found that most of the current research on the biological control of root rot diseases in Chinese medicinal materials was mostly limited to the verification of the inhibitory effect of Trichoderma strains on the growth of the pathogenic microbes. Studies on the induction effect of Trichoderma on Chinese medicinal materials are not in depth. Studies on the responding mechanisms of most Chinese medicinal materials to Trichoderma are highly absent. Moreover, there are few reports on field experiments, which indicates that there is a long way to go before Trichoderma is widely applied in the farming practice of Chinese medicinal materials. To sum up, this paper aimed to link the present and the future and advocated further relevant research and more experiments on the application of Trichoderma in the farming of Chinese medicinal materials.

[DUS testing guidelines for new varieties of Chinese medicinal plants].

A rich diversity of wild medicinal plant resources is distributed in China, but the breeding of new plant varieties of Chinese medicinal plants started late and the breeding level is relatively weak. Chinese medicinal plant resources are the foundation for new varieties breeding, and the plant variety rights(PVP) are of great significance for the protection and development of germplasm resources. However, most Chinese medicinal plants do not have a distinctness, uniformity, and stability(DUS) testing guideline. The Ministry of Agriculture and Rural Affairs has put 191 plant species(genera) on protection lists, of which only 30 are medicinal species(genera). At the same time, only 29 of 293 species(genera) plants in the Protection List of New Plant Varieties of the People's Republic of China(Forest and Grass) belong to Chinese medicinal plants. The number of PVP applications and authorization of Chinese medicinal plants is rare, and the composition of variety is unreasonable. Up to now, 29 species(genera) of DUS test guidelines for Chinese medicinal plants have been developed. Some basic problems in the breeding of new varieties of Chinese medicinal plants have appeared, such as the small number of new varieties and insufficient utilization of Chinese medicinal plant resources. This paper reviewed the current situation of breeding of new varieties of Chinese medicinal plants and the research progress of DUS test guidelines in China and discussed the application of biotechnology in the field of Chinese medicinal plant breeding and the existing problems in DUS testing. This paper guides the further application of DUS to protect and utilize the germplasm resources of Chinese medicinal plants.

[Application of tissue culture technology of medicinal plants in sustainable development of Chinese medicinal resources].

Chinese medicinal resources are the cornerstone of the sustainable development of traditional Chinese medicine industry. However, due to the fecundity of species, over-exploitation, and limitations of artificial cultivation, some medicinal plants are depleted and even endangered. Tissue culture, a breakthrough technology in the breeding of traditional Chinese medicinal materials, is not limited by time and space, and can allow the production on an annual basis, which plays an important role in the protection of Chinese medicinal resources. The present study reviewed the applications of tissue culture of medicinal plants in the field of Chinese medicinal resources, including rapid propagation of medicinal plant seedlings, breeding of novel high-yield and high-quality cultivars, construction of a genetic transformation system, and production of secondary metabolites. Meanwhile, the current challenges and suggestions for the future development of this field were also proposed.

[Medicinal plant microbiome: advances and prospects].

Medicinal plants are the main source of clinical medication in traditional Chinese medicine(TCM). China has achieved large-scale cultivation and production of medicinal plants. As an important resource for the sustainable development of agriculture in the future, microorganisms can also promote the green, ecological and high-quality development of Chinese medicine agriculture. However, research on the medicinal plant microbiome is still limited. Therefore, based on the development timeline of microbiome research, the present study reviewed the origin, technology, and hotspots of microbiome research and proposed some suggestions for future research according to the advances in medicinal plant microbiome.(1)Systematic investigation of medicinal plant microbiome on the species, genus, and family levels should be carried out on the medicinal plants of different chemotypes in order to reveal the coevolution of the microorganisms and their host plants.(2)Spatial and temporal research on medicinal plant microbiome should be performed to reveal the effects of microorganisms on the growth, development, and secondary metabolite accumulation of medicinal plants, as well as the underlying mechanisms.(3)Model medicinal plant species should be selected and microorganism-plant interaction research models should be established.(4)Core microbiome of medicinal plants should be explored for the future application of crucial microbes in the sustaina-ble agriculture of Chinese medicine.(5)Breeding of medicinal plant-associated microbes should be carried out to lay the foundation for novel medicinal plant breeding strategies.(6)High-throughput sequencing, traditional incubation, and isolation of microbes should be combined to study medicinal plant microbiome, thereby promoting the exploitation and application of uncultured microbial strains.(7)Platforms for the preservation of medicinal plant-associated microbe strains and data of their metabolites should be established and the exchange of information and cooperation between these platforms should be subsequently enhanced. With these suggestions, the efficient and rapid development of medicinal plant microbiome research is expected to be promoted.

[Comparison of transcriptome of Atractylodes lancea rhizome and exploration of genes for sesquiterpenoid biosynthesis].

This study compared the transcriptome of Atractylodes lancea rhizome at different development stages and explored genes encoding the key enzymes of the sesquiterpenoid biosynthesis pathway. Specifically, Illumina NovaSeq 6000 was employed for sequencing the cDNA libraries of A. lancea rhizome samples at the growth stage(SZ), flowering stage(KH), and harvesting stage(CS), respectively. Finally, a total of 388 201 748 clean reads were obtained, and 16 925, 8 616, and 13 702 differentially expressed genes(DEGs) were identified between SZ and KH, KH and CS, and SZ and CS, separately. Among them, 53 genes were involved in the sesquiterpenoid biosynthesis pathways: 9 encoding 6 enzymes of the mevalonic acid(MVA) pathway, 15 encoding 7 enzymes of the 2-C-methyl-D-erythritol-4-phosphate(MEP) pathway, and 29 of sesquiterpenoid and triterpenoid biosynthesis pathway. Weighted gene co-expression network analysis(WGCNA) yielded 12 genes related to sesquiterpenoid biosynthesis for the SZ, 1 gene for the KH, and 1 gene for CS, and several candidate genes for sesquiterpenoid biosynthesis were discovered based on the co-expression network. This study laid a solid foundation for further research on the sesquiterpenoid biosynthesis pathway, analysis of the regulation mechanism, and mechanism for the accumulation of sesquiterpenoids in A. lancea.

The proteome and phosphoproteome of maize pollen uncovers fertility candidate proteins.

Maize is unique since it is both monoecious and diclinous (separate male and female flowers on the same plant). We investigated the proteome and phosphoproteome of maize pollen containing modified proteins and here we provide a comprehensive pollen proteome and phosphoproteome which contain 100,990 peptides from 6750 proteins and 5292 phosphorylated sites corresponding to 2257 maize phosphoproteins, respectively. Interestingly, among the total 27 overrepresented phosphosite motifs we identified here, 11 were novel motifs, which suggested different modification mechanisms in plants compared to those of animals. Enrichment analysis of pollen phosphoproteins showed that pathways including DNA synthesis/chromatin structure, regulation of RNA transcription, protein modification, cell organization, signal transduction, cell cycle, vesicle transport, transport of ions and metabolisms, which were involved in pollen development, the following germination and pollen tube growth, were regulated by phosphorylation. In this study, we also found 430 kinases and 105 phosphatases in the maize pollen phosphoproteome, among which calcium dependent protein kinases (CDPKs), leucine rich repeat kinase, SNF1 related protein kinases and MAPK family proteins were heavily enriched and further analyzed. From our research, we also uncovered hundreds of male sterility-associated proteins and phosphoproteins that might influence maize productivity and serve as targets for hybrid maize seed production. At last, a putative complex signaling pathway involving CDPKs, MAPKs, ubiquitin ligases and multiple fertility proteins was constructed. Overall, our data provides new insight for further investigation of protein phosphorylation status in mature maize pollen and construction of maize male sterile mutants in the future.

Corrigendum to "Ethanol Extract from Ampelopsis sinica Root Exerts Anti-Hepatitis B Virus Activity via Inhibition of p53 Pathway In Vitro".

[This corrects the article DOI: 10.1093/ecam/neq011.].

Ethanol Extract from Ampelopsis sinica Root Exerts Anti-Hepatitis B Virus Activity via Inhibition of p53 Pathway In Vitro.

Ampelopsis sinica root is widely used in Chinese folk medicine for treating liver disorders caused by the hepatitis B virus (HBV). The present study was performed in order to investigate the anti-HBV activity and mechanisms of the ethanol extract from A. sinica root (EASR) in vitro. The antiviral activity of EASR was examined by detecting the levels of HBsAg, HBeAg and extracellular HBV DNAs in stable HBV-producing human hepatoblastoma HepG2 2.2.15 cells. We found that EASR effectively suppressed the secretion of HBsAg and HBeAg from HepG2 2.2.15 cells in a dose-dependent manner, and it also suppressed the amount of extracellular HBV DNA. After EASR treatment, the percentage of apoptotic cells was found to be significantly higher than that of control by flow cytometric analysis. A luciferase reporter gene assay was used to determine the effects of EASR on the activities of HBV promoters and intracellular signaling pathways. The results showed that EASR selectively inhibited the activities of HBV promoters (Cp, S1p and Fp) and the p53 signaling pathway in HepG2 cells significantly. These data indicate that EASR exerts anti-HBV effects via inhibition of HBV promoters and the p53-associated signaling pathway, which helps to elucidate the mechanism underlying the potential therapeutic value of EASR.

In vitro antiviral activity of lutein against hepatitis B virus.

Despite the availability of an effective vaccine, the hepatitis B virus (HBV) infection and its treatment remains one of the foremost public health problems in the world. The present study was performed in order to investigate the anti-HBV activity of lutein in vitro. The antiviral activity of lutein was examined by detecting the levels of HBsAg, HBeAg and extracellular HBV DNA in stable HBV-producing human hepatoblastoma HepG2 2.2.15 cells. It was found that lutein effectively suppressed the secretion of HBsAg from HepG2 2.2.15 cells in a dose-dependent manner, and it also suppressed the amount of extracellular HBV DNA. A luciferase reporter gene assay was used to determine the effects of lutein on the activities of HBV promoters. The results showed that lutein inhibited the activity of HBV full-length promoter (Fp). These data indicate that lutein possesses an anti-HBV activity and exerts its antivirus effects via inhibition of HBV transcription.

BmTx3B, a novel scorpion toxin from Buthus martensi Karsch, inhibits delayed rectifier potassium current in rat hippocampal neurons.

AIM: To examine the effect of BmTx3B, a novel short-chain peptide isolated from the venom of Asian scorpion Buthus martensi Karsch, on voltage-gated potassium channels. METHODS: Two types of voltage-dependent potassium currents were recorded from dissociated hippocampal neurons of neonatal rat in whole-cell voltage-clamp mode, and separated based upon their kinetic properties. RESULTS: BmTx3B (10-100 micromol/L) selectively inhibited the delayed rectifier potassium current (I(K)), without affecting the fast transient potassium current (I(A)). The inhibition of the peptide on I(K) was reversible, concentration-dependent and voltage-independent. BmTx3B did not affect the steady-state activation and inactivation kinetics of the current. CONCLUSION: The short-chain scorpion peptide BmTx3B selectively blocked the delayed rectifier potassium channel.