scholarly journals First Report of Alfalfa Root Rot Caused by Plectosphaerella cucumerina in Inner Mongolia Autonomous Region of China

Plant Disease ◽  
2021 ◽  
Author(s):  
Yan-qin Zhao ◽  
Kai Shi ◽  
Xiuying Yu ◽  
Li-juan Zhang
Keyword(s):  
Root Rot ◽  
Inner Mongolia ◽  
Its Sequences ◽  
Economic Losses ◽  
Conidial Suspension ◽  
Autonomous Region ◽  
First Report ◽  
Alfalfa Field ◽  
Inner Mongolia Autonomous Region ◽  
Brown Root Rot

Alfalfa (Medicago sativa L.) is an important forage crop with high nutrition for animal feed. In May 2016, a disease showing brown root rot was observed on alfalfa collected from several farms in Tongliao City (44°17′ N; 121°29′ E), Inner Mongolia Autonomous Region of China. The incidence of brown root rot was approximately 50 to 70% in the 2-year-old alfalfa field. Infected alfalfa exhibited varying degrees of decay in the tap root. Symptomatic roots were cut into 0.5-cm pieces, surface disinfected with 70% ethanol for 5 s and 0.1% HgCl2 for 35 s, then rinsed with sterilize distilled water three times, and placed onto potato dextrose agar (PDA) at 26°C in the dark. After 5 days, hyphal tips of the growing colonies were transferred onto PDA plates for purification. Forty-four isolates belonging to five fungal species were obtained from 20 diseased root samples. Six of the isolates resembled the genus Plectosphaerella. Colonies of these isolates were white to cream in color with sparse aerial mycelium, and then gradually became salmon pink with slimy or moist mycelium. The hyphae were transparent and branched. Colonies produced numerous hyphal coils with conidiophores. Conidiogenous cells and conidia were both hyaline, solitary, and smooth. Conidia were 4 to 8.5 ×1.2 to 4.8 µm (n= 100), 0 to 1 septum, elliptical and ovoid, and aggregating to form a head (Palm et al. 1995). According to these morphological characteristics, the fungus was identified as P. cucumerina (Lindf.) (Carlucci et al. 2012). To confirm the identification, the genomic DNA of two representative isolates was extracted and their internal transcribed spacer (ITS) region was amplified and sequenced with the primer pair ITS1/ITS4 (White et al. 1990). The ITS sequences of the two isolates were deposited in GenBank (acc. nos. MN915126 and MN915127). The two ITS sequences showed 99 to 100% identical to known P. cucumerina strains CBS 131739 (acc. no. KY662258.1) (Su et al. 2017) and MP313 (acc. no. KC756835.1) from alfalfa in China (Wen et al. 2015). To test for pathogenicity, a set of 15 alfalfa seedlings (cv. Aohan) were root-dipped in the conidial suspension of one of the isolates (1×105 conidia /ml) prepared from 7-day-old cultures on PDA. Inoculated seedlings were transplanted in three pots (10×15 cm) with sterilized nursery soil. Another set of five alfalfa seedlings inoculated with sterile water only served as the controls. Treated alfalfa seedlings were maintained in a greenhouse at 25°C to 28°C under a 12-h photoperiod. After 25 days, the roots of all inoculated plants showed brown lesions. P. cucumerina was reisolated from symptomatic tissue. No symptoms were observed on the control plants. P. cucumerina was previously reported on alfalfa in the fields of Huanxi Country (36°20′ N; 107°21′), Gansu Province, China (Wen et al. 2015). To our knowledge, this is the first report of P. cucumerina causing root rot of alfalfa in Inner Mongolia Autonomous Region, China. This disease may cause serious economic losses in the region. It is needed to develop effective management strategies for control of this disease.

scholarly journals First report of root rot on Dendrobium officinale caused by Fusarium incarnatum-equiseti species complex in Zhejiang Province, China

Plant Disease ◽  
2021 ◽  
Author(s):  
Yihua Yang ◽  
Zhenyan Cao ◽  
Jintian Tang ◽  
Yang Song ◽  
Xuping Shentu ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Root Rot ◽  
Species Complex ◽  
Zhejiang Province ◽  
Dendrobium Officinale ◽  
Economic Losses ◽  
Conidial Suspension ◽  
Sterile Water ◽  
Complex Span ◽  
First Report

Dendrobium officinale Kimura et Migo is a rare and valuable Chinese herb cultivated in Zhejiang and Yunnan Provinces, China, which is known for its functions as an anti-neoplastic and for lowering the blood sugar (Cheng et al., 2019). In September and October of 2018 and 2019, symptoms of root rot on D. officinale were observed with an incidence of 15–20% in Wuyi County, Zhejiang Province, China. The pathogen mainly infected roots causing severe root rot, which resulted in significant economic losses. At the early stage of this disease, the stalk turned brown, then the whole plant rotted from bottom to top within a few days. Symptomatic roots were cut into small pieces (1.0 cm × 1.0 cm) and disinfected successively by submersion in 75% ethanol for 30 s and 1% NaClO for 30 s under aseptic conditions. After rinsing with sterile water three times and air drying, segments were placed on potato dextrose agar (PDA). After incubation at 25 °C for 5 d in the dark, white to pale cream colored colonies were produced. The average mycelial growth rate was 15.2–18.5 mm day-1 at 25 ℃. Macroconidia were falciform with three to five septa and (18.0−32.0)×(3.0−5.0) μm in size. Microconidia were fusiform with two to three septa (7.0–10.0)×(2.1–3.0) μm. Based on morphological characteristics of macroconidia, and microconidia, isolates were identified as Fusarium incarnatum-equiseti species complex (span style="font-family:'Times New Roman'; font-size:12pt">FIESC) (Avila et al., 2019). The internal transcribed spacer (ITS) region, translation elongation factor (EF-1α), RNA polymerase largest subunit (RPB1), and RNA polymerase second largest subunit (RPB2) gene were amplified and sequenced respectively using ITS1/ITS4, EF1/EF2, Fa/G2R and 5f2/7cr primers (O’Donnell et al., 2010). BLASTN analysis of FUSARIUM-ID using ITS (Accession NO. MW172977), EF-1α (Accession NO. MW172978, RPB1(Accession NO. MW172979), and RPB2(Accession NO. MW172980) showed 99.8%, 100%, 99.74%, and 98.63% identity to FIESC isolates NRRL43619, NRRL34059, NRRL32864, and NRRL32175, respectively. To verify pathogenicity, ten 1-year-old healthy D. officinale plants were used for inoculation tests. One milliliter of a conidial suspension (106 conidia ml-1) was pipetted onto the soil around the base of D. officinale plants per pot. Ten plants, which were treated with sterile water, were used as the control. All plants were maintained in a climatic chamber (26 ± 1 ℃, 70–80% relative humidity and a photoperiod of 16:8 [L: D] h). Seven days later, all inoculated plants showed typical symptoms of root rot identical to those observed in the fields. Control plants remained symptomless and healthy. The pathogenicity analysis was repeated three times. Pathogens re-isolated from symptomatic plants were identified as FIESC species by morphology observation and sequence analysis. To our knowledge, this is the first report of root rot caused by FIESC species on D. officinale in Zhejiang, China.

scholarly journals Salinadaptatus halalkaliphilus gen. nov., sp. nov., a haloalkaliphilic archaeon isolated from salt pond in Inner Mongolia Autonomous Region, China

2020 ◽  
Author(s):  
Qiong Xue ◽  
Zhenqiang Zuo ◽  
Heng Zhou ◽  
Jian Zhou ◽  
Shengjie Zhang ◽  
...  
Keyword(s):  
Inner Mongolia ◽  
Type Strain ◽  
Amino Acid Sequences ◽  
Rrna Gene ◽  
Strictly Aerobic ◽  
Autonomous Region ◽  
Salt Pond ◽  
A Genome ◽  
The Family ◽  
Inner Mongolia Autonomous Region

A haloalkaliphilic strain XQ-INN 246T was isolated from the sediment of a salt pond in Inner Mongolia Autonomous Region, China. Cells of the strain were rods, motile and strictly aerobic. The strain was able to grow in the presence of 2.6–5.3 M NaCl (optimum concentration is 4.4 M) at 30–50 °C (optimum temperature is 42 °C) and pH 7.0–10.0 (optimum pH is 8.0–8.5). The whole genome sequencing of strain XQ-INN 246T revealed a genome size of 4.52 Mbp and a DNA G+C content of 62.06 mol%. Phylogenetic tree based on 16S rRNA gene sequences and concatenated amino acid sequences of 122 single-copy conserved proteins revealed a robust lineage of the strain XQ-INN 246T with members of related genera of the family Natrialbaceae . The strain possessed the polar lipids of phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. No glycolipids were detected. Based on phylogenetic analysis, phenotypic characteristics, chemotaxonomic properties and genome relatedness, the isolate was proposed as the type strain of a novel species of a new genus within the family Natrialbaceae, for which the name Salinadaptatus halalkaliphilus gen. nov., sp. nov. is proposed. The type strain is XQ-INN 246T (=CGMCC 1.16692T=JCM 33751T).

scholarly journals First Report of Fusarium stem and root rot of Gerbera jamesonii caused by Fusarium incarnatum in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Shuning Chen ◽  
Wei Sun ◽  
Huizhu Yuan ◽  
Xiaojing Yan
Keyword(s):  
Root Rot ◽  
Vascular System ◽  
Elongation Factor ◽  
Morphological Observation ◽  
Conidial Suspension ◽  
Gerbera Jamesonii ◽  
Gene Sequences ◽  
Plastic Container ◽  
First Report ◽  
Brown Discoloration

Gerbera (Gerbera jamesonii Bolus) is an important cut flower grown globally. In 2020, gerbera plants (Redaicaoyuan, Baimawangzi, and Hongditan cultivars) with roots, crowns, and stems rot were found in a greenhouse in Nanping, Fujian, China. Approximately 30% of the 60,000 plants showed symptoms. Diseased plants were stunted with chlorotic leaves. The leaves and flower heads were wilted and withered. Brown discoloration with red to black streaks occurred in the vascular system of the crown and stem. The stem pieces (3×3 mm) showing the symptom were surface-disinfected with 1% NaClO for 1 min and washed three times with sterilized water. The stem pieces were then dried and placed on potato dextrose agar (PDA) at 25℃ inside a dark chamber. Ten single-spored isolates were identified as Fusarium incarnatum based on morphological features. White to light brown mycelia were observed among the isolates on PDA medium. Falculate, multicelluar, straight to slightly curved macroconidia produced in monophialide sporodochia without distinctive foot shaped basal cell; and chlamydospores produced in some isolates (Leslie and Summerell). The size of macroconidia was 36.4 ± 5.20 × 4.6 ± 1.3 μm (n = 100) with 3 to 5 septates. Microconidia were mostly 0 to 1 septate measured 14.6 ± 1.9 × 2.6 ± 0.5 μm (n=100). Based on the morphological observation, isolates were further identified by molecular method. The ITS1/4 region combined with partial gene fragments of translation elongation factor (EF-1α, primer EF1/EF2, Geiser et al.) and calmodulin (CAM, primer CL1/CL2A, O’Donnell.) from the isolates were amplified and sequenced. All of the three tested isolates showed identical gene sequences. Sequences amplified from one represented isolate FIN-1 were submitted to Genbank. BLAST searches revealed that ITS1/4 (MW527088), EF-1α (MW556488), and CAM (MW556487) had 99.22%, 99.53%, 99.42% identity compared to F. incarnatum (MN480497, MN233577, and LN901596, respectively) in GenBank. FUSARIUM-ID (Geiser et al. 2004) analysis also showed 99 to 100% similarity with sequences of the F. incarnatum-equiseti species complex (FIESC) (FD_01636 for CAM, FD_01643 for EF-1α). The phylogenetic analysis was conducted using neighbor-joining algorithm based on the ITS, EF-1α, and CAM gene sequences. The isolate was clustered with F. incarnatum clade. Then, the pathogenicity of the fungus was confirmed by performing Koch’s postulates. Pure single-spored cultures were grown on carboxymethyl-cellulose (CMC) medium for sporulation. G. jamesonii plants used for pathogenicity tests were grown on sterilized potting soil in a plastic container to the ten-leaf stage prior to inoculation. Spores harvested from the CMC medium were adjusted to a concentration of 1×105 conidial/ml. Twelve healthy rooted gerbera seedlings were inoculated by drenching 10 ml of the conidial suspension onto roots. Twelve gerbera seedlings treated with 10 ml sterile water served as control treatments. Plants were grown in the glasshouse at temperatures of 23°C, relative humidity >70%, and 16 h light per day. After 10 days, blackening stems and withered leaf edges began to appear on inoculated seedlings, whereas control seedlings remained healthy. F. incarnatum was consistently re-isolated from the symptomatic stems, whereas no isolates were obtained from the control seedlings. The assay was conducted twice. To the best of our knowledge, this is the first report of F. incarnatum causing stem and root rot on G. jamesonii.

scholarly journals First Report of Fusarium solani Causing Root Rot on Coptis chinensis in Southwestern China

Plant Disease ◽  
2014 ◽  
Vol 98 (9) ◽  
pp. 1273-1273 ◽  
Author(s):  
X.-M. Luo ◽  
J.-L. Li ◽  
J.-Y. Dong ◽  
A.-P. Sui ◽  
M.-L. Sheng ◽  
...  
Keyword(s):  
Fusarium Solani ◽  
Root Rot ◽  
Southwestern China ◽  
Molecular Characteristics ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Storage Roots ◽  
Coptis Chinensis ◽  
Causal Organism ◽  
First Report

China is the world's largest producer country of coptis (Coptis chinensis), the rhizomes of which are used in traditional Chinese medicine. Since 2008, however, root rot symptoms, including severe necrosis and wilting, have been observed on coptis plants in Chongqing, southwestern China. Of the plants examined from March 2011 to May 2013 in 27 fields, 15 to 30% were covered with black necrotic lesions. The leaves of infected plants showed wilt, necrotic lesions, drying, and death. The fibrous roots, storage roots, and rhizomes exhibited brown discoloration and progressive necrosis that caused mortality of the infected plants. Infected plants were analyzed to identify the causal organism. Discoloration of the internal vascular and cortical tissues of the rhizomes and taproots was also evident. Symptomatic taproots of the diseased coptis were surface sterilized in 1% sodium hypochlorite for 2 min, rinsed in sterile distilled water for 2 min, and then air-dried in sterilized atmosphere/laminar flow. Small pieces of disinfested tissue (0.3 cm in length) were transferred to petri dishes containing potato dextrose agar (PDA) supplemented with 125 μg ml–1 streptomycin sulfate and 100 μg ml–1 ampicillin, and incubated for 5 days at 25°C with a 12-h photoperiod. Four distinct species of fungal isolates (HL1 to 4) derived from single spores were isolated from 30 plants with root rot symptoms collected from the study sites. To verify the pathogenicity of individual isolates, healthy coptis plants were inoculated by dipping roots into a conidial suspension (106 conidia/ml) for 30 min (15 plants per isolate), as described previously (1). Inoculated plants were potted in a mixture of sterilized quartz sand-vermiculite-perlite (4:2:1, v/v) and incubated at 25/18°C and 85 to 90% relative humidity (day/night) in a growth chamber with a daily 16-h photoperiod of fluorescent light. Plants dipped in sterile distilled water were used as controls. After 15 days, symptoms similar to those observed in the field were observed on all plants (n = 15) that were inoculated with HL1, but symptoms were not observed on plants inoculated with HL2, HL3, and HL4, nor on control plants. HL1 was re-isolated from symptomatic plants but not from any other plants. Morphological characterization of HL1 was performed by microscopic examination. The septate hyphae, blunt microconidia (2 to 3 septa) in the foot cell and slightly curved microconidia in the apical cell, and chlamydospores were consistent with descriptions of Fusarium solani (2). The pathogen was confirmed to be F. solani by amplification and sequencing of the ribosomal DNA internal transcribed spacer (rDNA-ITS) using the universal primer pair ITS4 and ITS5. Sequencing of the PCR product revealed a 99 to 100% similarity with the ITS sequences of F. solani in GenBank (JQ724444.1 and EU273504.1). Phylogenetic analysis (MEGA 5.1) using the neighbor-joining algorithm placed the HL1 isolate in a well-supported cluster (97% bootstrap value based on 1,000 replicates) with JQ724444.1 and EU273504.1. The pathogen was thus identified as F. solani based on its morphological and molecular characteristics. To our knowledge, this is the first report of root rot of coptis caused by F. solani in the world. References: (1) K. Dobinson et al. Can. J. Plant Pathol. 18:55, 1996. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Oxford, 2006.

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