Publications by authors named "Ya Yu Zhang"

7 Publications

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Occurrence of postharvest snow rot caused by on Asian ginseng in China.

Plant Dis 2021 Jul 20. Epub 2021 Jul 20.

Chinese Academy of Agricultural Sciences, 12661, Institute of Special Wild Economic Animal and Plant Science, Chinese Academy of Agricultural Sciences, Changchun, Jilin, China;

Asian ginseng () is a valuable medicinal plant that is commercially cultivated in China. A long postharvest storage period is required before ginseng is processed. From October 2019 to May 2020, snow rot was observed on the roots of 4- and 5-year-old fresh ginseng stored in three cold storage facilities located in Tonghua and Changbai cities in northeastern China, which are the most important regions for Asian ginseng production. We sampled 1,000 ginseng roots from the three cold storage facilities, and the average disease incidence was 21%. Initially, sparse hyphae and microsclerotia appeared on the root epidermis. Lesions gradually softened and the epidermis detached easily. Multiple infected sites slowly converged, resulting in the formation of a dense complex of multiple sclerotia and thick hyphae on the surface of the ginseng root as well as internal decay. The infection eventually spread to the adjacent ginseng roots (Fig. 1). Sixteen diseased ginseng roots were collected and then sclerotia were removed from the root surface, immersed in 1% NaClO for 2 min, rinsed three times with sterile water, and placed on potato dextrose agar (PDA) containing streptomycin (40 μg/mL) in Petri dishes. After a 3-day incubation at 20 °C in darkness, 22 suspected Sclerotinia isolates were obtained. Isolates SN1 and SN2 were randomly selected for identification. On PDA, fast-growing colonies produced white, sparse, powdery, and cotton-like aerial mycelia, and the reverse side showed the same color (Fig. 2). Small and white sclerotial primordia formed 3 days later and a ring of sclerotia was detected at the plate periphery. At 7 to 10 days after incubation, the mature sclerotia were black, spherical-to-subspherical, and elongated or fused to form irregular shapes. Each Petri dish produced 55-65 sclerotia, measuring 1.1 × 1.2 to 3.2 × 3.9 mm (n = 100). The sclerotia were firmly attached to the agar surface. The isolates were initially identified as sp. (Saito 1997). After sequencing the nuclear ribosomal internal transcribed spacer region (MW927134 and MW927135) and the β-tubulin gene (MW929179 and MW929180) (White et al. 1990; Glass and Donaldson 1995), BLAST searches revealed 100% homology with JX262268 and JX296007 of the published strain KGC-S0601, respectively. The pathogenicity of the two isolates was tested using detached ginseng roots. Briefly, healthy roots were washed, surface-disinfested with 75% alcohol, and rinsed with sterile water. Mycelial plugs (5 mm diameter) removed from the margin of actively growing colonies on PDA were placed on the ginseng roots. For each isolate, four roots were inoculated, with two plugs per root. Additionally, PDA plugs without mycelia were used as the negative control. The roots were placed in a fresh-keeping box at 20 °C in darkness and evaluated after 7 days. The pathogenicity test was repeated twice. The symptoms on the inoculated roots were the same as those observed on the roots during cold storage, whereas the control roots remained symptomless. The same fungus was reisolated consistently from all infected roots and its identity was confirmed by resequencing, thereby fulfilling Koch's postulates. To the best of our knowledge, this is the first report of causing postharvest snow rot on Asian ginseng in China. The occurrence of this disease threatens the postharvest storage of Asian ginseng. Hence, effective management strategies must be developed.
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http://dx.doi.org/10.1094/PDIS-04-21-0868-PDNDOI Listing
July 2021

First Report of Anthracnose of American Ginseng caused by in Northeast China.

Plant Dis 2021 May 4. Epub 2021 May 4.

Chinese Academy of Agricultural Sciences, 12661, Institute of Special Wild Economic Animal and Plant Science, Chinese Academy of Agricultural Sciences, Juye Street No. 4899, Changchun, Jilin, China, 130112.

American ginseng () is a medicinal plant that is commercially cultivated in China. Anthracnose is a devastating disease of American ginseng, with annual production losses exceeding 20%. In July 2019, anthracnose of American ginseng was observed on 3-year-old plants in Fusong County, Jilin Province, China, the most important region of American ginseng. Round or irregular-shaped, brown, sunken and necrotic lesions (5 to 11 mm in diameter), occasionally with a concentric ring or surrounded by brown halos, were detected on leaves (Fig. 1). Multiple lesions gradually coalesced, eventually causing yellowing and wilting. More than 36% of plants in a 30-ha field were infected. Symptomatic leaves (n=16) were collected and the diseased tissue was cut into small pieces, immersed in 1% NaOCl for 2 min, rinsed three times with sterile water, and placed on acidified potato dextrose agar (PDA) in Petri dishes. After incubation in darkness at 25°C for 4 days, 15 suspected single-spore isolates purified in water agar were obtained. The isolate XTJ2 was randomly selected for identification. On PDA, colonies were white to gray, occasionally mixed with gray-black strips, and the reverse was similar to the surface. Colonies on nutrient-poor agar (SNA) were flat, thin, floccose, with an entire margin, whitish to pale gray with the same colors on the reverse. The conidia were hyaline, smooth-walled, straight with a rounded base and apex, ranging from 11.1 to 21.2 × 4.0 to 5.5 μm (n=100), with length/width =3.5. Conidia were initially aseptate, but became septate with age. Setae were dark brown with a slightly acute tip, 2 to 3-septa, and 31.5 to 81.6 μm long. Appressoria were rarely observed, brown, smooth-walled, oval, bullet-shaped or irregular. Chlamydospores were not observed. The isolate was initially identified as sp. (Damm et al. 2019). Initial BLAST searches of XTJ2 sequences of the rDNA internal transcribed spacer region (GenBank accession no. MW048745), a partial glyceraldehyde-3-phosphate dehydrogenase (MW053381), chitin synthase 1 (MW053382), histone H3 (MW053383), actin (MW053384) and beta-tubulin (MW053385) in GenBank showed that the sequences were respectively 100% similar to Colletotrichum sojae sequences: NR_158358, MG600810, MG600860, MG600899, MG600954 and MG601016 (Carbone and Kohn 1999; Crous et al. 2004;Guerber et al. 2003). The identity of XTJ2 was confirmed by constructing a phylogenetic tree combining all loci, which grouped the isolate and the type strain of into one clade (Fig. 2). The sequences of all isolates were genetically identical to the XTJ2 sequences. For pathogenicity tests, 15 healthy 3-year-old plants grown in five pots were spray-inoculated with the XTJ2 conidial suspension (1×105 spores/mL), and the same number of plants were sprayed with water as the control. This experiment was repeated twice. Plants were kept in a greenhouse (28°C, natural light, and 85% relative humidity) under clear plastic bags. After 10 days, inoculated leaves exhibited symptoms that were similar to those observed in the field, whereas the controls were symptomless. The same fungus was recovered and sequenced, and its identity was confirmed by a phylogenetic analysis. This is the first report of causing anthracnose of American ginseng in China, being a potential threat to the production of this culture. More studies on the epidemiology of this disease are needed to improve disease management.
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http://dx.doi.org/10.1094/PDIS-11-20-2440-PDNDOI Listing
May 2021

Multi-Locus Phylogeny and Taxonomy of the Fungal Complex Associated With Rusty Root Rot of in China.

Front Microbiol 2020 16;11:618942. Epub 2020 Dec 16.

Engineering Research Center, Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun, China.

Panax rusty root rot caused by the species complex is a devastating disease, and it is one of the main factors contributing to the difficulty in continual cropping. Rusty root rot occurs in all ginseng fields, but little is known about the taxonomy of the fungal pathogen complex, especially and -like species. Rusty root rot samples were collected from commercial ginseng cultivation areas of China, and the pathogens were isolated and purified as single spores. Based on the combination analysis of multiple loci (rDNA-ITS, , , , , LSU, , , and SSU) and morphological characteristics, the pathogens causing ginseng rusty root rot were determined. Fungal isolates were obtained from infected roots in 56 locations within main cultivation areas in China. A total of 766 strains were identified as , -like and species, including (55.0%), (21.7%), (10.9%), (2.0%), (1.3%), (1.3%), (2.0%), (0.5%), sp. (0.5%), and (1.5%), and four novel species, (1.0%), (1.0%), (0.8%) and (0.5%), with a total of 14 species. As the pathogen present in the highest proportion, was the most prevalent and damaging species, unlike the pathogens reported previously. All of the examined strains were proven to cause ginseng rusty root rot. Our results indicate that the taxonomy of the fungal complex associated with ginseng rusty root rot includes , -like genera (, , and ) and .
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http://dx.doi.org/10.3389/fmicb.2020.618942DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7772391PMC
December 2020

Occurrence of Causing Root Rot on in northeastern China.

Plant Dis 2020 Dec 1. Epub 2020 Dec 1.

Chinese Academy of Agricultural Sciences, 12661, Institute of Special Wild Economic Animal and Plant Science, Chinese Academy of Agricultural Sciences, Changchun, Jilin, China;

Bunge (Fabaceae) is a perennial medicinal herb widely cultivated in China. In June 2018, root rot was observed on two-year-old plants in Chaoyangshan town (northeastern China). In a 40-ha field, over 40% of the plants exhibited root rot and the infected area ranged from 10 to 70% of the roots. The roots first exhibited circular or irregular brown, sunken and necrotic lesions, and finally multiple lesions coalesced. The infected root surface was destroyed, showing rusty and dry rot (Fig. 1). Symptoms were concentrated in the main roots (Carlucci et al. 2017). The aboveground parts of infected plants did not initially show symptoms but gradually wilted; 7.6% of the plants died when root decay became severe. Infected roots were not used for processing and were not marketable. Ten infected roots were collected from May to October 2018 from the above location. The diseased root tissue was cut into 25 mm3 pieces, immersed in 1% NaOCl for 2 minutes, rinsed three times with sterile water and placed on water agar in Petri plates. After 15 days of incubation at 20°C, 11 single-spore isolates were obtained. Isolates HQ1 and HQ2 were randomly selected for morphological and molecular identification. Colonies grown for 10 days produced yellow, cottony to felty aerial mycelium on potato dextrose agar. Conidiophores originating laterally or terminally from the mycelium were solitary to loosely aggregated and unbranched or sparsely branched. Macroconidia predominated and were cylindrical, with a tendency to gradually widen towards the tip; 1- to 3-septate; and 20.2 to 31.0 × 3.0 to 6.7 µm (n=100). Microconidia had mostly 0¬- to 1-septate and 8.6 to 16.7 × 1.9 to 5.1 µm (n=100) (Fig. 1). Chlamydospores were rare, but occasional chlamydospore chains were observed. The isolates were tentatively identified as (Cabral et al. 2012a). Further confirmation of the two isolates was conducted by DNA sequencing of the internal transcribed spacer (ITS, GenBank accession no. MN558983 and MN558984), β-tubulin (, MN561692 and MN561693), histone 3 (, MN561694 and MN561695), and translation elongation factor (, MN561696 and MN561697) genes (Cabral et al. 2012b). These sequences had 99 to 100% match with D. torresensis (JF735362 for ITS, JF735492 for , JF735681 for and JF735870 for TEF). Phylogenetic trees based on analyses of a concatenated alignment of all loci grouped these isolates into the clade (Fig. 2). The same two isolates were tested for pathogenicity. Healthy two-year-old plants were taken from the field, and their roots were disinfected with 75% alcohol for 3 minutes, rinsed with sterile water three times, immersed in a 1×10/ml spore suspension or sterile water (control) for 10 minutes, transferred to a tray filled with sterile sand and placed in a greenhouse (12 h photoperiod, 25°C). Twelve plants grown in three pots were used for each isolate, and the same number of plants were inoculated as a control. This experiment was repeated three times. After one month, inoculated plant roots showed the same symptoms as those observed in the field, while the controls remained symptomless and no pathogen was recovered. The same fungus was reisolated from all the infected plants and confirmed by sequencing all of the above genes. This is the first report of causing root rot in in China. The occurrence of this disease poses a threat, and management strategies need to be developed.
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http://dx.doi.org/10.1094/PDIS-02-20-0278-PDNDOI Listing
December 2020

Seed-Associated Fungal Diversity and the Molecular Identification of with Potential Threat to Ginseng () in China.

Plant Dis 2020 Feb 18;104(2):330-339. Epub 2019 Dec 18.

Institute of Special Wild Economic Animal and Plant Science, Chinese Academy of Agricultural Sciences, Changchun, Jilin, 130112, China.

The utility of traditional methods for detecting seed-borne fungi is limited by the fact some fungi are unculturable or difficult to isolate. The seed-borne pathogens affecting cultivation have not been fully characterized. Seed-borne fungi can be identified based on the high-throughput sequencing of internal transcribed spacer (ITS) amplicons. A hierarchical clustering tree diagram analysis based on operational taxonomic units revealed a relationship between the seed-borne fungi and the region from which the seeds were collected. This study analyzed the fungal diversity on 30 ginseng seed samples from the main ginseng-producing areas of China. The 50 most abundant genera were identified including those responsible for ginseng diseases, , , , , , , and . species, which are the primary causes of root rot, were detected in all seed samples. The results of a phylogenetic analysis indicated that the seed-borne fungal species originating from the same region were closely related. Fungi on ginseng seeds from eight different regions were divided into eight clades, suggesting they were correlated with the local storage medium. A total of 518 isolates were obtained and 10 species identified, all of which can be detrimental to ginseng production. Pathogenicity tests proved that seed-borne species can infect ginseng seedlings and 2-year-old ginseng root, with potentially adverse effects on ginseng yield and quality.
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http://dx.doi.org/10.1094/PDIS-09-19-1817-REDOI Listing
February 2020

[Photosynthetic characteristics and active ingredients differences of Asarum heterotropoides var. mandshuricum under different light irradiance].

Zhongguo Zhong Yao Za Zhi 2019 Jul;44(13):2753-2761

College of Herbal Medicine,Jilin Agricultural University Changchun 130118,China.

Chlorophyll content,leaf mass to per area,net photosynthetic rate and bioactive ingredients of Asarum heterotropoides var. mandshuricum,a skiophyte grown in four levels of solar irradiance were measured and analyzed in order to investigate the response of photosynthetic capability to light irradiance and other environmental factors. It suggested that the leaf mass to per area of plant was greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in the decrease of leaf mass to per area at every phenological stage. At expanding leaf stage,the rate of Chla and Chlb was 3. 11 when A. heterotropoides var. mandshuricum grew in full light irradiance which is similar to the rate of heliophytes,however,the rate of Chla and Chlb was below to 3. 0 when they grew in shading environment. The content of Chla,Chlb and Chl( a+b) was the greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in its decreasing remarkably( P<0. 05). The rate of Chla and Chlb decreased but the content of Chla,Chlb and Chl( a+b) increased gradually with continued shading. The maximum value of photosynthetically active radiation appeared at 10: 00-12: 00 am in a day. The maximum value of net photosynthetic rate appeared at 8: 30-9: 00 am and the minimum value appeared at 14: 00-14: 30 pm at each phenological stage if plants grew in full sunlight. However,when plants grew in shading,the maximum value of net photosynthetic rate appeared at about 10: 30 am and the minimum value appeared at 12: 20-12: 50 pm at each phenological stage. At expanding leaf stage and flowering stage,the average of net photosynthetic rate of leaves in full sunlight was remarkably higher than those in shading and it decreased greatly with decreasing of irradiance gradually( P < 0. 05). However,at fruiting stage,the average of net photosynthetic rate of leaves in full sunlight was lower than those in 50% and 28% full sunlight but higher than those in 12% full sunlight. All photosynthetic diurnal variation parameters of plants measured in four kinds of different irradiance at three stages were used in correlation analysis. The results suggested that no significant correlation was observed between net photosynthetic rate and photosynthetically active radiation,and significant negative correlation was observed between net photosynthetic rate and environmental temperature as well as vapor pressure deficit expect for 12% full sunlight. Positive correlation was observed between net photosynthestic rate and relative humidity expect for 12% full sunlight. Significant positive correlation was observed between net photosynthetic rate and stomatal conductance in the four light treatments. Only,in 12% full sunlight,the net photosynthetic rate was significantly related to photosynthetically active radiation rather than related to environmental temperature,vapor pressure deficit and relative humidity. In each light treatment,a significant positive correlation was observed between environmental temperature and vapor pressure deficit,relative humidity as well as stomatal conductance. Volatile oil content was 1. 46%,2. 16%,1. 56%,1. 30% respectively. ethanol extracts was 23. 44%,22. 45%,22. 18%,21. 12% respectively. Asarinin content was 0. 281%,0. 291%,0. 279% and 0. 252% respectively. The characteristic components of Asarum volatile oil of plant in different light treatments did not change significantly among different groups.
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http://dx.doi.org/10.19540/j.cnki.cjcmm.20190504.101DOI Listing
July 2019

[Relationship between R236C site in exon 7 of SP-B gene and respiratory distress syndrome in Han newborns in western Inner Mongolia].

Zhongguo Dang Dai Er Ke Za Zhi 2016 Sep;18(9):802-805

Department of Neonatology, Affiliated Hospital, Inner Mongolia Medical University, Hohhot 010059, China.

Objective: To detect and analyze the genetic variation in exon 7 of lung surfactant protein B (SP-B), and to investigate the relationship between the genetic variation and the incidence of neonatal respiratory distress syndrome (NRDS) in Han populations in western Inner Mongolia.

Methods: In the case-control study, 47 Han infants with NRDS were assigned to case group. All the 47 patients had the last three generations of their ancestors reside in western Inner Mongolia. Forty-seven Han newborns without NRDS were assigned to control group. PCR-based gene analysis was used to determine the mutation in exon 7 of SP-B gene and genotype and allele frequencies of the R236C site in exon 7 of SP-B gene.

Results: In Han newborns in western Inner Mongolia, there was no mutation in exon 7 of SP-B gene; two genotypes, CC and CT, were identified in the R236C site in exon 7 of SP-B gene. No TT genotype was found in the two groups. There were no significant differences in the genotype frequency of CC or CT as well as the allele frequency of C or T between the case and control groups (CC: 72% vs 85%, P>0.05; CT: 28% vs 15%, P>0.05; C: 85% vs 93%, P>0.05; T: 15% vs 7%, P>0.05).

Conclusions: There is no mutation in exon 7 of SP-B gene in Han infants with NRDS in western Inner Mongolia. There is no significant association between the gene polymorphism of the R236C site in exon 7 of SP-B gene and the incidence of NRDS in Han populations in that region.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7389981PMC
September 2016
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