First Report of Cyst Nematode (Heterodera elachista) on Zea mays in Gansu Province, China

The most globally recognized and economically important nematode on wheat is the cereal cyst nematode (CCN) complex (1). One of the most important species of this group is Heterodera filipjevi (Madžidov, 1981) Mulvey and Golden, 1983. During regular soil quarantine control in September 2010, Heterodera sp. cysts were found in soil samples originating from a wheat field in Gunaroš, Vojvodina Province, in northern Serbia. The wheat was a winter crop grown in a dryland production system and had an average cyst density of 2.50/100 cm3 of soil. Morphologically, the cysts were golden brown and lemon shaped with a posterior protuberance. The vulval cone was bifenestrate with horseshoe-shaped semifenestra, bullae, and underbridge. Cyst measurements (n = 30) ranged as follows: cyst length (without neck): 511.50 to 899.00 μm, cyst width: 201.50 to 682.00 μm, fenestral length: 44.80 to 65.60 μm, fenestral width: 24.00 to 40.00 μm, vulval bridge length: 12.80 to 20.80 μm, vulval bridge width: 6.40 to 14.40 μm, vulval slit: 6.00 to 12.80 μm, and underbridge length: 60.00 to 112.00 μm. The second-stage juveniles had an offset head, stylet with characteristic anchor-shaped basal knobs, four incisures, and a conical tail with a rounded tip. The J2 morphometrics (n = 30) were: length: 447.30 to 611.10 μm, width: 22.40 to 25.60 μm, stylet: 20.80 to 24.00 μm, tail length: 56.00 to 68.80 μm, tail width: 14.40 to 19.20 μm, and hyaline length: 35.20 to 44.80 μm. The ITS region was used for molecular analysis. Each DNA sample was extracted from a single cyst. Sequencing was done with primers TW81 and AB28 (2). In comparison with other H. filipjevi populations, the obtained sequence (GenBank Accession No. JX235959) revealed 99 to 100% similarity. Morphological and molecular data confirmed the existence of H. filipjevi. This is, to our knowledge, the first report of H. filipjevi from Serbia. Since wheat has important socioeconomic value for Serbia, after extensive surveys, additional phytosanitary measures may be necessary to prevent the spread of this parasite. References: (1) J. M. Nicol et al. Current Nematode Threats to World Agriculture. Genomics and Molecular Genetics of Plant-Nematode Interactions, Springer, New York, 2011. (2) A. M. Skantar et al. J. Nematol. 39:133, 2007.

Download Full-text

First report of Leptosphaeria biglobosa ‘canadensis’ causing blackleg on oilseed rape (Brassica napus) in China

Plant Disease ◽

10.1094/pdis-12-20-2735-pdn ◽

2021 ◽

Author(s):

Tao Luo ◽

Guoqing Li ◽

Long Yang

Keyword(s):

Brassica Napus ◽

Oilseed Rape ◽

Southern China ◽

Disease Incidence ◽

Morphological Characteristics ◽

Gansu Province ◽

Bootstrap Support ◽

First Report ◽

Fungal Isolates ◽

Leptosphaeria Biglobosa

Oilseed rape (Brassica napus L.) is one of the most important oilseed crops in China. It is widely cultivated in China, with winter oilseed rape in Yangtze River basin and in southern China, and spring oilseed rape in northern China. In August 2017, a survey for Leptosphaeria spp. on spring oilseed rape was conducted in Minle county, Zhangye city, Gansu Province, China. The symptoms typical of blackleg on basal stems of oilseed rape were observed in the field. A large number of black fruiting bodies (pycnidia) were present on the lesions (Fig. 1A). The disease incidence of basal stem infection in the surveyed field was 19%. A total of 19 diseased stems were collected to isolate the pathogen. After surface sterilizing (75% ethanol for 30 s, 5% NaOCl for 60 s, followed by rinsing in sterilized water three times), diseased tissues were cultured on acidified potato dextrose agar (PDA) plates at 20°C for 7 days. Twelve fungal isolates were obtained. All fungal isolates produced typical tan pigment on PDA medium, and produced pycnidia after two weeks (Fig. 1B). Colony morphological characteristics indicated that these isolates might belong to Leptosphaeria biglobosa. To confirm identification, multiple PCR was conducted using the species-specific primers LmacF, LbigF, LmacR (Liu et al. 2006). Genomic DNA of each isolate was extracted using the cetyltrimethylammonium bromide (CTAB) method. DNA samples of L. maculans isolate UK-1 and L. biglobosa isolate W10 (Cai et al. 2015) were used as references. Only a 444-bp DNA band was detected in all 12 isolates and W10, whereas a 333-bp DNA band was detected only in the UK-1 isolate (Fig. 1C). PCR results suggested that these 12 isolates all belong to L. biglobosa. In addition, the internal transcribed spacer (ITS) region of these 12 isolates was analyzed for subspecies identification (Vincenot et al. 2008). Phylogenetic analysis based on ITS sequence showed that five isolates (Lb1134, Lb1136, Lb1138, Lb1139 and Lb1143) belonged to L. biglobosa ‘brassicae’ (Lbb) with 78% bootstrap support, and the other seven isolates (Lb1135, Lb1137, Lb1140, Lb1141, Lb1142, Lb1144 and Lb1145) belonged to L. biglobosa ‘canadensis’ (Lbc) with 95% bootstrap support (Fig. 1D). Two Lbb isolates (Lb1134 and Lb1136) and two Lbc isolates (Lb1142 and Lb1144) were randomly selected for pathogenicity testing on B. napus cultivar Zhongshuang No. 9 (Wang et al. 2002). Conidial suspensions (10 μL, 1 × 107 conidia mL-1) of these four isolates were inoculated on needle-wounded cotyledons (14-day-old seedling), with 10 cotyledons (20 wounded sites) per isolate. A further 10 wounded cotyledons were inoculated with water and served as controls. Seedlings were maintained in a growth chamber at 20°C with 100% relative humidity and a 12-h photoperiod. After 7 days, cotyledons inoculated with the four isolates showed necrotic lesions in the inoculated wounds. Control cotyledons had no symptoms (Fig. 2). Fungi re-isolated from the infected cotyledons showed similar colony morphology as the original isolates. Therefore, L. biglobosa ‘brassicae’ and L. biglobosa ‘canadensis’ appear to be the pathogens causing the observed blackleg symptoms on spring oilseed rape in Gansu, China. In previous studies, L. biglobosa ‘brassicae’ has been found in many crops in China, including oilseed rape (Liu et al. 2014; Cai et al. 2015), Chinese radish (Raphanus sativus) (Cai et al. 2014a), B. campestris ssp. chinensis var. purpurea (Cai et al. 2014b), broccoli (B. oleracea var. italica) (Luo et al. 2018), ornamental kale (B. oleracea var. acephala) (Zhou et al. 2019a), B. juncea var. multiceps (Zhou et al. 2019b), B. juncea var. tumida (Deng et al. 2020) and Chinese cabbage (B. rapa subsp. pekinensis) (Yu et al. 2021 accepted). To the best of our knowledge, this is the first report of L. biglobosa ‘canadensis’ causing blackleg on B. napus in China.

Download Full-text

First Report of Carrot Cyst Nematode Heterodera carotae in Mexico: Morphological, Molecular Characterization, and Host Range Study

Journal of Nematology ◽

10.21307/jofnem-2018-021 ◽

2018 ◽

Vol 50 (2) ◽

pp. 229-242 ◽

Cited By ~ 4

Author(s):

Ilia Mariana Escobar-Avila ◽

Edgar Óliver López-Villegas ◽

Sergei A. Subbotin ◽

Alejandro Tovar-Soto

Keyword(s):

Host Range ◽

Molecular Characterization ◽

Cyst Nematode ◽

First Report ◽

Range Study

Download Full-text

Molecular and morphological exploration of a mixed population of two potato-parasiting nematode species, Globodera rostochiensis and G. pallida

Helminthologia ◽

10.2478/s11687-014-0201-3 ◽

2014 ◽

Vol 51 (1) ◽

pp. 3-6 ◽

Cited By ~ 3

Author(s):

O. Douda ◽

M. Zouhar ◽

M. Renčo ◽

M. Marek

Keyword(s):

Central Europe ◽

Nematode Species ◽

Globodera Rostochiensis ◽

Cyst Nematode ◽

Mixed Population ◽

Potato Field ◽

Cross Hybridization ◽

First Report ◽

Parasitic Species ◽

Plant Parasitic

Abstract In this work, we report results of molecular and morphological analyses of a potato field population of Globodera (Nematoda: Heteroderidae) species, in Slovakia. Unexpectedly, our data show a mixed occurrence of two potato cyst nematode species, Globodera rostochiensis and G. pallida, in this locality. To our knowledge, this is the first report of mixed occurrence of these economically important plant-parasitic species in the same locality in the Central Europe. In addition, this finding reinforces the possibility of the cross-hybridization between these two nematode species that might result in a generation of new genotypes.

Download Full-text

First Report of Potato Cyst Nematode Globodera pallida Infecting Potato (Solanum tuberosum) in Kenya

Plant Disease ◽

10.1094/pdis-11-17-1777-pdn ◽

2018 ◽

Vol 102 (8) ◽

pp. 1671-1671 ◽

Cited By ~ 7

Author(s):

H. Mburu ◽

L. Cortada ◽

G. Mwangi ◽

K. Gitau ◽

A. Kiriga ◽

...

Keyword(s):

Solanum Tuberosum ◽

Cyst Nematode ◽

Potato Cyst Nematode ◽

Globodera Pallida ◽

First Report

Download Full-text

First Report of Corn Cyst Nematode (Heterodera zeae) in Virginia

Plant Disease ◽

10.1094/pd-77-0647e ◽

1993 ◽

Vol 77 (6) ◽

pp. 647E ◽

Cited By ~ 4

Author(s):

J. D. Eisenback

Keyword(s):

Cyst Nematode ◽

First Report

Download Full-text

First Report of Erwinia persicinus Causing Wilting of Medicago sativa Sprouts in China

Plant Disease ◽

10.1094/pdis-10-11-0909 ◽

2012 ◽

Vol 96 (3) ◽

pp. 454-454 ◽

Cited By ~ 7

Author(s):

Z. F. Zhang ◽

Z. B. Nan

Keyword(s):

Medicago Sativa ◽

16S Rdna ◽

Acid Production ◽

Northwest China ◽

Gansu Province ◽

Microbiological Analysis ◽

Forage Crops ◽

First Report ◽

Production Of Hydrogen ◽

Hydrolysis Of

Medicago sativa L. is one of the most important perennial forage crops and has been cultivated for more than 2,000 years in China. A previously unreported sprout wilt disease of M. sativa, affecting as much as 25% of the seedlings, was observed in northwest China (Gansu Province) in March 2011. First symptoms on the sprouts were dehydration and yellowing. Within 24 to 48 h, the sprouts stopped growing, wilted, turned brown, and bacteria began oozing from the material. Three symptomatic sprout samples collected from a grower with the wilt problem were processed for microbiological analysis. Bacteria isolated from symptomatic samples produced a pink, diffusible pigment in King's medium B and nutrient agar supplemented with glucose, sucrose, and maltose. The three isolates were negative for gram stain reaction, oxidase, production of hydrogen sulfide and indole, growth in KCN broth, arginine dihydrolase activity, hydrolysis of casein, hydrolysis of gelatin, and acid production from L-arabinose, dulcitol, glycerol, lyxose, and starch. In contrast, they were positive for catalase, nitrate reduction, Voges-Proskauer, hydrolysis of aesculin, acid production from D-ribose, maltose and sucrose, assimilation of adonitol, L-lactate, mannitol, Myo-inositol, erythritol, sorbitol, and sucrose, and growth in 5% NaCl at 36°C. The 16S rDNA of three isolates (Cp1, Cp2, and Cp3) was amplified using the 7F (5′-CAGAGTTTGATCCTGGCT-3′) and 1540R (5′-AGGAGGTGATCCAGCCGCA-3′) primers. The sequences for the 1,428-bp amplicon from the isolates were identical (GenBank Accession No. JN900058) and had 99% sequence identity with 16S rDNA of Erwinia persicinus strains (including the type strain LMG 11254 [GenBank Accession No. Z96086.1], GS 04 [GenBank Accession No. DQ365580.1], LPPA 373 [GenBank Accession No. AJ937837.1], LPPA 408 [GenBank Accession No. AM294946.1], LMG 2691 [GenBank Accession No. AJ001190.1], and HK 204 [GenBank Accession No. NR_026049.1]). The three isolates were also evaluated in pathogenicity tests. Bacterial suspensions (108 CFU/ml) were spray inoculated on 7-day-old M. sativa sprouts of cv. Algonquin. The inoculated sprouts were placed onto 2% water agar in petri dishes (five sprouts per 9-cm dish) with four dishes for each bacterial isolate and control. The dishes were sealed with Parafilm for 2 days and held in an incubator at 25°C with a 12-h photoperiod. Assays were repeated twice. Symptoms that developed within 7 days were similar to those originally observed, whereas symptoms did not occur on control sprouts sprayed with sterile distilled water. Bacteria sharing the characteristics of the inoculated isolates were recovered from symptomatic sprouts, hence fulfilling Koch's postulates. E. persicinus has been isolated previously from Phaseolus vulgaris (1), Pisum sativum (2), tomato, banana, and cucumber (3). To our knowledge, this is the first report of E. persicinus from M. sativa. References: (1) A. J. González et al. Plant Dis. 89:109, 2005. (2) A. J. González et al. Plant Dis. 91:460, 2007. (3) M. V. Hao et al. Int. J. Syst. Bacteriol. 40:379, 1990.

Download Full-text

First report of a potato cyst nematode,Globodera rostochiensis, on potato, in Iran

Plant Pathology ◽

10.1111/j.1365-3059.2009.02135.x ◽

2010 ◽

Vol 59 (2) ◽

pp. 412-412 ◽

Cited By ~ 3

Author(s):

M. Gitty ◽

Z. Tanha Maafi

Keyword(s):

Globodera Rostochiensis ◽

Cyst Nematode ◽

Potato Cyst Nematode ◽

First Report

Download Full-text

First report of Fusarium avenaceum causing Leaf Spot on Angelica sinensis in China

Plant Disease ◽

10.1094/pdis-08-21-1753-pdn ◽

2021 ◽

Author(s):

Zikun Zhang ◽

Jianqiang Zhang ◽

Wanxia Zhang ◽

Zhian Kou ◽

Xinfang Wang ◽

...

Keyword(s):

Leaf Spot ◽

Chinese Herb ◽

Gansu Province ◽

Fusarium Avenaceum ◽

Angelica Sinensis ◽

Conidial Suspension ◽

Data Set ◽

First Report ◽

Initial Symptoms ◽

Β Tubulin

Angelica sinensis (Oliv) Diels (Umbelliferae) is a popular Chinese herb that is mainly distributed in Gansu Province, China, accounting for more than 90% of the national output and sales. A survey for diseases of A. sinensis in Gansu Province in August 2019 found foliar disease with an incidence of 60 to100%, and severities ranging from 5 to 15%. The disease mainly occurred in late July and August. The initial symptoms included many light brown, small lesions, round or irregular in shape, which gradually increased in size. White mycelia was visible in the lesions. Severely affected leaves became chlorotic, withered and died. In the Angelica planting area in Weiyuan County (33°26′N, 104°02′E) diseased leaves from 20 plants were collected by the five-point sampling method (Zheng et al. 2018), and small samples (4 × 4 mm2) wee cut from the border between diseased and healthy tissue, successively sterilized with 75% ethanol for 30 sec, washed three times with sterilized water and dried on sterilized filter paper, and placed on potato dextrose agar plates. After 5 days at 25°C, five morphologically similar colonies were obtained. Colonies were somewhat round with pink overall and formed abundant fluffy white mycelium in the center. Conidia were solitary, macrospores slender, straight to slightly falcate with 2 to 6 septa, and ranged from 20.0 to 77.6 µm × 2.5 to 3.6 µm (n=50). The microspores were elliptical and ranged from 3.0 to 8.0 µm × 2.5 to 3.0 µm (n=5). The strong pink pigment was observed on the reverse side of the PDA culture. The morphological characteristics were consistent with the description of Fusarium avenaceum (Parikh et al. 2018; Jahedi et al. 2019). To further identify the strains, the internal transcribed spacer (ITS), β-tubulin, translation elongation factor 1α (EF1-α), and RNA polymerase second largest subunit (RPB2) gene regions were amplified with ITS1/ITS4, Bt2a/Bt2b, EF1/EF2, and 5f2/7cr (Glass and Donaldson 1995; O’Donnell et al. 2010; White et al. 1990), respectively. The sequences of the five strains were identical, and that of representative strain K0721 were deposited in GenBank (ITS, MZ389899; TUB2, MZ398139; EF1-α, MZ388462; RPB2, MZ394004). BLAST analysis revealed that the ITS, β-tubulin, EF1-α, and RPB2 sequences were 100% (563/563), 100% (423/423), 99% (643/649), and 99% (930/935) homology, with those of F. avenaceum (KP295511.1, KY475586.1, KU999088.1, and MH582082.1), respectively. A multigene phylogenetic tree was inferred by Maximum likelihood phylogenetic analyses based on the combined data set with ITS, EF1-α and RPB2. The strain K0721 was clustered with F. avenaceum. Pathogenicity tests were performed on five 1-month-old healthy plants in plastic pots (20 cm. diam.) with sterilized soil. Each was sprayed with 50 μl of a conidial suspension (1×104 conidia/mL), and 5 healthy plants were sprayed with sterile water as controls. Small lesions were observed after 5 days at 25℃ in a greenhouse. Symptoms were similar to those observed under field conditions. Control plants remained symptomless. Six isolates were reisolated from infected leaves and all confirmed to be F. avenaceum based on morphological observations and molecular identification. To our knowledge, only Septoria anthrisci has been previously reported as a pathogen of A. sinensis leaf spot (Wang et al. 2018), and this is the first report of F. avenaceum causing this disease. This discovery needs to be considered in developing and implementing disease management programs in A. sinensis production.

Download Full-text