scholarly journals First Report of Root Rot Caused by the Fusarium oxysporum Species Complex on Codonopsis pilosula in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Xia Zhao ◽  
Yue Liang ◽  
UWAREMWE CONSTANTINE ◽  
Liu Yang ◽  
Tian Yuan ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Root Rot ◽  
Species Complex ◽  
Tween 20 ◽  
Group Method ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Codonopsis Pilosula

Codonopsis pilosula Franch., also known as Dangshen, is an important medicinal plant in China. It is widely cultivated for a major income of local farmers in Dingxi, Gansu Province. Its dried roots have the effects of supplementing vital energy, nourishing spleen and lung, enhancing organic immunity, helping depressurization, and improving microcirculation, etc., for humans. In June to October, 2018-2020, root rot disease was observed on C. pilosula with incidences up to 20% in the Dingxi region. We collected ten diseased and healthy plants from Dingxi (35°06′N, 104°29′E, 2206 m a.s.l.) in October 2019. The rotting root tissues were sterilized with 70% ethanol for 30 s and 3% NaOCl for 5 min and placed on potato dextrose agar (PDA) plates incubated at 25℃to isolate the pathogen (Shang et al. 2014). From the similar fungal cultures isolated after 7 days on PGA, isolate B17 was purified for morphological and molecular characterization. Its colony appeared light purple and produced long aerial hyphae. Slightly curved macroconidia (12.3 to 31.7 × 3.1 to 5.1 μm, n=40) and oval-ellipsoid and cylindrical microconidia (6.1 to 9.9 × 2.8 to 4.5 μm, n=30) were observed. The internal transcribed spacer region (ITS) and the translation elongation factor-1 alpha (TEF-1α) gene were amplified using primers ITS1/ITS4 and EF-1/EF-2 (Uwaremwe et al. 2020), respectively. The 489 bp (ITS) and 631 bp (TEF-1α) sequences were deposited in GenBank (Accession No. MN744360 and MN786974, respectively). The ITS sequence had 100% homology to isolate JJF2 (No. MN626452, ITS) (Ma et al. 2020), and the TEF-1α sequence had 100% homology to isolate Fo353 (No. KM065860) (Koyyappurath et al. 2016) of Fusarium oxysporum Schlecht. emend. Snyder & Hansen, which caused root rot of Panax ginseng and Vanilla planifolia, respectively. A phylogenetic tree was generated using the unweighted pair-group method with arithmetic average in the MycoBank database (O’Donnell et al. 2015), which clustered isolate B17 in the F. oxysporum species complex. Twenty 1-year-old plants of C. pilosula were inoculated with were inoculated by dipping the washed roots in a conidial suspension (2 ×106 conidia/ml added with 0.2% Tween 20) for 20 min before transplanted into pots (16 × 16 × 23 cm) with four plants per pot filled with sterilized peat and soil mixture (2:1 v/v) and grown in a greenhouse at 26oC with >70% humidity and 16 h light. Sterilized water added with 0.2% Tween 20 was used as a control. One week after inoculation, the leaves of pathogen-inoculated plants became yellow, and wilting occurred at the leaf tips 18 days later. Some of the inoculated plants died 45 days after inoculation, and the low part of roots had dark brown to black lesions and became rotting. The control plants did not show symptoms. The pathogenicity test was repeated three times with the same fungus isolated from the infected root tissue. To the best of our knowledge, this is the first report that F. oxysporum causes root rot on C. pilosula in China. F. oxysporum is a serious threat to C. pilosula cultivation, and the finding of this pathogen provides a clear target for root rot control.

scholarly journals First report of Fusarium falciforme (FSSC 3+4) causing root rot on chickpea in Mexico

Plant Disease ◽  
2021 ◽  
Author(s):  
Sixto Velarde Felix ◽  
Victor Valenzuela ◽  
Pedro Ortega ◽  
Gustavo Fierros ◽  
Pedro Rojas ◽  
...  
Keyword(s):  
Fusarium Solani ◽  
Root Rot ◽  
Species Complex ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Aerial Mycelium ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Single Spore ◽  
First Report

Chickpea (Cicer aretinium L.) is a legume crop of great importance worldwide. In January 2019, wilting symptoms on chickpea (stunted grow, withered leaves, root rot and wilted plants) were observed in three fields of Culiacan Sinaloa Mexico, with an incidence of 3 to 5%. To identify the cause, eighty symptomatic chickpea plants were sampled. Tissue from roots was plated on potato dextrose agar (PDA) medium. Typical Fusarium spp. colonies were obtained from all root samples. Ten pure cultures were obtained by single-spore culturing (Ff01 to Ff10). On PDA the colonies were abundant with white aerial mycelium, hyphae were branched and septae and light purple pigmentation was observed in the center of old cultures (Leslie and Summerell 2006). From 10-day-old cultures grown on carnation leaf agar medium, macroconidias were falciform, hyaline, with slightly curved apexes, three to five septate, with well-developed foot cells and blunt apical cells, and measured 26.6 to 45.8 × 2.2 to 7.0 μm (n = 40). The microconidia (n = 40) were hyaline, one to two celled, produced in false heads that measured 7.4 to 20.1 (average 13.7) μm × 2.4 to 8.9 (average 5.3) μm (n = 40) at the tips of long monophialides, and were oval or reniform, with apexes rounded, 8.3 to 12.1 × 1.6 to 4.7 μm; chlamydospores were not evident. These characteristics fit those of the Fusarium solani (Mart.) Sacc. species complex, FSSC (Summerell et al. 2003). The internal transcribed spacer and the translation elongation factor 1 alpha (EF1-α) genes (O’Donnell et al. 1998) were amplified by polymerase chain reaction and sequenced from the isolate Ff02 and Ff08 (GenBank accession nos. KJ501093 and MN082369). Maximum likelihood analysis was carried out using the EF1-α sequences (KJ501093 and MN082369) from the Ff02 and Ff08 isolates and other species from the Fusarium solani species complex (FSSC). Phylogenetic analysis revealed the isolate most closely related with F. falciforme (100% bootstrap). For pathogenicity testing, a conidial suspension (1x106 conidia/ml) was prepared by harvesting spores from 10-days-old cultures on PDA. Twenty 2-week-old chickpea seedlings from two cultivars (P-2245 and WR-315) were inoculated by dipping roots into the conidial suspension for 20 min. The inoculated plants were transplanted into a 50-hole plastic tray containing sterilized soil and maintained in a growth chamber at 25°C, with a relative humidity of >80% and a 12-h/12-h light/dark cycle. After 8 days, the first root rot symptoms were observed on inoculating seedlings and the infected plants eventually died within 3 to 4 weeks after inoculation. No symptoms were observed plants inoculated with sterilized distilled water. The fungus was reisolated from symptomatic tissues of inoculated plants and was identified by sequencing the partial EF1-α gene again and was identified as F. falciforme (FSSC 3 + 4) (O’Donnell et al. 2008) based on its morphological characteristics, genetic analysis, and pathogenicity test, fulfilling Koch’s postulates. The molecular identification was confirmed via BLAST on the FusariumID and Fusarium MLST databases. Although FSSC has been previously reported causing root rot in chickpea in USA, Chile, Spain, Cuba, Iran, Poland, Israel, Pakistan and Brazil, to our knowledge this is the first report of root rot in chickpea caused by F. falciforme in Mexico. This is important for chickpea producers and chickpea breeding programs.

scholarly journals First Report of Stem Wilt and Root Rot of Schlumbergera truncata Caused by Fusarium oxysporum f. sp. Opuntiarum in Southern Italy

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 846-846 ◽  
Author(s):  
F. Lops ◽  
F. Cibelli ◽  
M. L. Raimondo ◽  
A. Carlucci
Keyword(s):  
Fusarium Oxysporum ◽  
Root Rot ◽  
Southern Italy ◽  
Nucleotide Sequences ◽  
Control Treatment ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
Fungal Isolation ◽  
First Report ◽  
Fusarium Sp

Schlumbergera truncata (Haw.) Moran, belonging to the Cactaceae, is a very common ornamental cactus in southern Italy. In November 2011, sudden stem wilt and root rot was observed in about 45% of vegetatively propagated plants cultivated as potted ornamental plants in a commercial greenhouse in Cerignola (Foggia Province, Apulia, Italy). The roots and collars of the plants showed brown rot. Yellow sunken lesions that were similar to cortical cankers were detected at basal level of the stem. Ten plants with these symptoms were analyzed by fungal isolation techniques. Small (0.5 cm) tissue portions from root, collar, and basal stem were plated on potato dextrose agar (PDA) after disinfection with 75% ethanol for 1 to 2 min, 0.2% NaOCl for 1 to 2 min, and a wash with sterile distilled water. A fungal isolate that was morphologically similar to Fusarium sp. was isolated from 85% of these tissue samples. It had nucleotide sequences of the internal transcribed spacer region (ITS1-5.8S-ITS2) of ribosomal DNA (GenBank Accession No. KC196121) 100% identical to those of the comparable sequences of Fusarium oxysporum (HQ651161). The nucleotide sequences of its translation elongation factor 1-α (EF-1α) gene (KC196120) showed 100% identity to sequences of F. oxysporum f. sp. opuntiarum (DQ837689, AF246881) retrieved from GenBank. Pathogenicity tests were performed at 22 ± 3°C on 18 45-day-old plants of S. truncate by adding of a 5-ml aliquot of conidial suspension adjusted to 5 × 106 conidia/ml to soil of each plant. Six non-inoculated plants were used for a control treatment and sprayed with 5 ml of sterilized water. Plants were maintained in greenhouse at 22 ± 3°C. After 10 days, nine of the inoculated plants showed wilting, and after 45 days, all of them were dead, with root and collar rot and lesions on the basal stem. Control plants were symptomless. Koch's postulates were fulfilled as the pathogen was reisolated from all of the symptomatic tissues and identified as Fusarium sp. On the basis of 3-septate macroconidia (mean 31.75 × 3.21 μm; range, 26 to 35 μm long, 3.0 to 4.2 μm wide), aseptate microconidia, single chlamydospores, and monophialide conidiophores on carnation leaf agar, and molecular analyses, the fungus was identified as F. oxysporum f. sp. opuntiarum (Speg) (1,2,3). In Italy, F. oxysporum f. sp. opuntiarum was reported as basal stem rot of Echinocactus grusoni (4). To our knowledge, this is the first report of stem wilt and root rot of S. truncata caused by F. oxysporum f. sp. opuntiarum in Italy. References: (1) W. Gerlach. Phytopathol. Z. 74:197, 1972. (2) W. L. Gordon. Can. J. Bot. 43:1309, 1965. (3) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, University Park, 1983. (4) G. Polizzi et al. Plant Dis. 88:85, 2004.

scholarly journals First Report of Phomopsis citri Associated with Dieback of Citrus lemon in India

Plant Disease ◽  
2014 ◽  
Vol 98 (9) ◽  
pp. 1281-1281 ◽  
Author(s):  
S. Mahadevakumar ◽  
Vandana Yadav ◽  
G. S. Tejaswini ◽  
S. N. Sandeep ◽  
G. R. Janardhana
Keyword(s):  
Fungal Pathogen ◽  
The United States ◽  
Apical Region ◽  
Post Inoculation ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
Productivity Level ◽  
First Report ◽  
Dieback Disease

Lemon (Citrus lemon (L.) Burm. f.) is an important fruit crop cultivated worldwide, and is grown practically in every state in India (3). During a survey conducted in 2013, a few small trees in a lemon orchard near Mysore city (Karnataka) (12°19.629′ N, 76°31.892′ E) were found affected by dieback disease. Approximately 10 to 20% of trees were affected as young shoots and branches showed progressive death from the apical region downward. Different samples were collected and diagnosed via morphological methods. The fungus was consistently isolated from the infected branches when they were surface sanitized with 1.5% NaOCl and plated on potato dextrose agar (PDA). Plates were incubated at 26 ± 2°C for 7 days at 12/12 h alternating light and dark period. Fungal colonies were whitish with pale brown stripes having an uneven margin and pycnidia were fully embedded in the culture plate. No sexual state was observed. Pycnidia were globose, dark, 158 to 320 μm in diameter, and scattered throughout the mycelial growth. Both alpha and beta conidia were present within pycnidia. Alpha conidia were single celled (5.3 to 8.7 × 2.28 to 3.96 μm) (n = 50), bigittulate, hyaline, with one end blunt and other truncated. Beta conidia (24.8 to 29.49 × 0.9 to 1.4 μm) (n = 50) were single celled, filiform, with one end rounded and the other acute and curved. Based on the morphological and cultural features, the fungal pathogen was identified as Phomopsis citri H.S. Fawc. Pathogenicity test was conducted on nine healthy 2-year-old lemon plants via foliar application of a conidial suspension (3 × 106); plants were covered with polythene bags for 6 days and maintained in the greenhouse. Sterile distilled water inoculated plants (in triplicate) served as controls and were symptomless. Development of dieback symptoms was observed after 25 days post inoculation and the fungal pathogen was re-isolated from the inoculated lemon trees. The internal transcribed spacer region (ITS) of the isolated fungal genomic DNA was amplified using universal-primer pair ITS1/ITS4 and sequenced to confirm the species-level diagnosis (4). The sequence data of the 558-bp amplicon was deposited in GenBank (Accession No. KJ477016.1) and nBLAST search showed 99% homology with Diaporthe citri (teleomorph) strain 199.39 (KC343051.1). P. citri is known for its association with melanose disease of citrus in India, the United States, and abroad. P. citri also causes stem end rot of citrus, which leads to yield loss and reduction in fruit quality (1,2). Dieback disease is of serious concern for lemon growers as it affects the overall productivity level of the tree. To the best of our knowledge, this is the first report of P. citri causing dieback of lemon in India. References: (1) I. H. Fischer et al. Sci. Agric. (Piracicaba). 66:210, 2009. (2) S. N. Mondal et al. Plant Dis. 91:387, 2007. (3) S. P. Raychaudhuri. Proc. Int. Soc. Citriculture 1:461, 1981. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

scholarly journals First Report of Nigrospora osmanthi Causing Leaf Spot on Tartary Buckwheat in China

Plant Disease ◽  
2020 ◽  
Author(s):  
Quan Shen ◽  
Xixu Peng ◽  
Feng He ◽  
Shaoqing Li ◽  
Zuyin Xiao ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Leaf Spot ◽  
Plant Pathogens ◽  
Hunan Province ◽  
Tartary Buckwheat ◽  
Tween 20 ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Sterile Water ◽  
First Report

Buckwheat (Fagopyrum tataricum) is a traditional short-season pseudocereal crop originating in southwest China and is cultivated around the world. Antioxidative substances in buckwheat have been shown to provide many potential cardiovascular health benefits. Between August and November in 2019, a leaf spot was found in several Tartary buckwheat cv. Pinku1 fields in Xiangxiang County, Hunan Province, China. The disease occurred throughout the growth cycle of buckwheat after leaves emerged, and disease incidence was approximately 50 to 60%. Initially infected leaves developed a few round lesions, light yellow to light brown spots. Several days later, lesions began to enlarge with reddish brown borders, and eventually withered and fell off. Thirty lesions (2×2 mm) collected from three locations with ten leaves in each location were sterilized in 70% ethanol for 10 sec, in 2% sodium hypochlorite for 30 sec, rinsed in sterile water for three times, dried on sterilized filter paper, and placed on a potato dextrose PDA with lactic acid (3 ml/L), and incubated at 28°C in the dark for 3 to 5 days. Fungal colonies were initially white and later turned black with the onset ofsporulation. Conidia were single-celled, black, smooth, spherical to subspherical, and measured 9.2 to 15.6 µm long, and 7.1 to 11.6 µm wide (n=30). Each conidium was terminal and borne on a hyaline vesicle at the tip of conidiophores. Morphologically, the fungus was identified as Nigrospora osmanthi (Wang et al. 2017). Identification was confirmed by amplifying and sequencing the ITS region, and translation elongation factor 1-alpha (TEF1-α) and partial beta-tublin (TUB2) genes using primers ITS1/ITS4 (Mills et al. 1992), EF1-728F/EF-2 (Carbone and Kohn 1999; O’Donnell et al. 1998) and Bt-2a/Bt-2b (Glass et al. 1995), respectively. BLAST searches in GenBank indicated the ITS (MT860338), TUB2 (MT882054) and TEF1-α (MT882055) sequences had 99.80%, 99% and 100% similarity to sequences KX986010.1, KY019461.1 and KY019421.1 of Nigrospora osmanthi ex-type strain CGMCC 3.18126, respectively. A neighbor-joining phylogenetic tree constructed using MEGA7.0 with 1,000 bootstraps based on the concatenated nucleotide sequences of the three genes indicated that our isolate was closely related to N. osmanthi. Pathogenicity test was performed using leaves of healthy F. tataricum plants. The conidial suspension (1 × 106 conidia/ml) collected from PDA cultures with 0.05% Tween 20 buffer was used for inoculation by spraying leaves of potted 20-day-old Tartary buckwheat cv. Pinku1. Five leaves of each plant were inoculated with spore suspensions (1 ml per leaf). An equal number of control leaves were sprayed with sterile water to serve as a control. The treated plants were kept in a greenhouse at 28°C and 80% relative humidity for 24 h, and then transferred to natural conditions with temperature ranging from 22 to 30°C and relative humidity ranging from 50 to 60%. Five days later, all N. osmanthi-inoculated leaves developed leaf spot symptoms similar to those observed in the field, whereas control leaves remained healthy. N. osmanthi was re-isolated from twelve infected leaves with frequency of 100%, fulfilling Koch’s postulates. The genus Nigrospora has been regarded by many scholars as plant pathogens (Fukushima et al. 1998) and N. osmanthi is a known leaf blight pathogen for Stenotaphrum secundatum (Mei et al. 2019) and Ficus pandurata (Liu et al. 2019) but has not been reported on F. tataricum. Nigrospora sphaerica was also detected in vegetative buds of healthy Fagopyrum esculentum Moench (Jain et al. 2012). To our knowledge, this is the first report of N. osmanthi causing leaf spot on F. tataricum in China and worldwide. Appropriate strategies should be developed to manage this disease.

scholarly journals First Report on Ovate-leaf Atractylodes Damping-off Caused by Fusarium oxysporum species Complex in South Korea

Plant Disease ◽  
2021 ◽  
Author(s):  
Oliul Hassan ◽  
Taehyun Chang
Keyword(s):  
South Korea ◽  
Fusarium Oxysporum ◽  
Species Complex ◽  
Disease Incidence ◽  
Fusarium Species ◽  
Morphological Characteristics ◽  
Conidial Suspension ◽  
Sterile Water ◽  
Damping Off ◽  
First Report

In South Korea, ovate-leaf atractylodes (OLA) (Atractylodes ovata) is cultivated for herbal medicine. During May to June 2019, a disease with damping off symptoms on OLA seedlings were observed at three farmer fields in Mungyeong, South Korea. Disease incidence was estimated as approximately 20% based on calculating the proportion of symptomatic seedlings in three randomly selected fields. Six randomly selected seedlings (two from each field) showing damping off symptoms were collected. Small pieces (1 cm2) were cut from infected roots, surface-sterilized (1 minute in 0.5% sodium hypochlorite), rinsed twice with sterile water, air-dried and then plated on potato dextrose agar (PDA, Difco, and Becton Dickinson). Hyphal tips were excised and transferred to fresh PDA. Six morphologically similar isolates were obtained from six samples. Seven-day-old colonies, incubated at 25 °C in the dark on PDA, were whitish with light purple mycelia on the upper side and white with light purple at the center on the reverse side. Macroconidia were 3–5 septate, curved, both ends were pointed, and were 19.8–36.62 × 3.3–4.7 µm (n= 30). Microconidia were cylindrical or ellipsoid and 5.5–11.6 × 2.5–3.8 µm (n=30). Chlamydospores were globose and 9.6 –16.3 × 9.4 – 15.0 µm (n=30). The morphological characteristics of present isolates were comparable with that of Fusarium species (Maryani et al. 2019). Genomic DNA was extracted from 4 days old cultures of each isolate of SRRM 4.2, SRRH3, and SRRH5, EF-1α and rpb2 region were amplified using EF792 + EF829, and RPB2-5f2 + RPB2-7cr primer sets, respectively (Carbone and Kohn, 1999; O'Donnell et al. 2010) and sequenced (GenBank accession number: LC569791- LC569793 and LC600806- LC600808). BLAST query against Fusarium loci sampled and multilocus sequence typing database revealed that 99–100% identity to corresponding sequences of the F. oxysporum species complex (strain NRRL 28395 and 26379). Maximum likelihood phylogenetic analysis with MEGA v. 6.0 using the concatenated sequencing data for EF-1α and rpb2 showed that the isolates belonged to F. oxysporum species complex. Each three healthy seedlings with similar sized (big flower sabju) were grown for 20 days in a plastic pot containing autoclaved peat soil was used for pathogenicity tests. Conidial suspensions (106 conidia mL−1) of 20 days old colonies per isolate (two isolates) were prepared in sterile water. Three pots per strain were inoculated either by pouring 50 ml of the conidial suspension or by the same quantity of sterile distilled water as control. After inoculation, all pots were incubated at 25 °C with a 16-hour light/8-hour dark cycle in a growth chamber. This experiment repeated twice. Inoculated seedlings were watered twice a week. Approximately 60% of the inoculated seedlings per strain wilted after 15 days of inoculation and control seedlings remained asymptomatic. Fusarium oxysporum was successfully isolated from infected seedling and identified based on morphology and EF-1α sequences data to confirm Koch’s postulates. Fusarium oxysporum is responsible for damping-off of many plant species, including larch, tomato, melon, bean, banana, cotton, chickpea, and Arabidopsis thaliana (Fourie et al. 2011; Hassan et al.2019). To the best of our knowledge, this is the first report on damping-off of ovate-leaf atractylodes caused by F. oxysporum in South Korea. This finding provides a basis for studying the epidemic and management of the disease.

scholarly journals First Report of Fusarium Wilt of Lavandula pubescens Caused by Fusarium oxysporum in Saudi Arabia

Plant Disease ◽  
2010 ◽  
Vol 94 (9) ◽  
pp. 1163-1163 ◽  
Author(s):  
K. Perveen ◽  
N. Bokhari
Keyword(s):  
Saudi Arabia ◽  
Fusarium Oxysporum ◽  
Vascular Tissue ◽  
Agricultural Research ◽  
Indian Agricultural Research Institute ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Potential Threat ◽  
King Saud University ◽  
First Report

In November 2008, a wilt of lavender (Lavandula pubescens) seedlings was observed in the greenhouse at King Saud University, Riyadh, Saudi Arabia. Affected seedlings were wilted and the root system was poorly developed. Diseased stems developed a dark coloration that extended down to the roots. Vascular tissue of the affected seedlings appeared red or brown. Isolations consistently yielded a fungus growing from the discolored stem tissue when placed on potato dextrose agar. The macroscopic characteristics of the colony, as well as microscopic structures, were used to identify the fungus as Fusarium oxysporum (2). Oval to elliptical microconidia without septa and originating from short phialides were used to distinguish the species from F. solani (1). The fungus was authenticated by the ITCC (Indian Type Collection Centre), Indian Agricultural Research Institute, New Delhi, India, and given I.D. No. 7532.09. For conducting further experiments, healthy seedlings of L. pubescens were obtained from the botanical garden of the King Saud University and grown in steam-sterilized soil. Healthy seedlings of lavender were inoculated using a root-dip method with a conidial suspension (1 × 107 CFU/ml) of one strain of F. oxysporum obtained from infected plants. Inoculated seedlings were then transplanted into steam-sterilized soil. Plants inoculated with sterilized water (1 ml per plant) served as control treatments. Wilt symptoms and vascular discoloration in the roots and crown developed within 20 days on all plants inoculated with the pathogen, while control plants remained asymptomatic. F. oxysporum was consistently reisolated from symptomatic plants. The pathogenicity test was conducted twice. To our knowledge, this is the first report of F. oxysporum on L. pubescens in Saudi Arabia or elsewhere in the world, and this newly identified disease may be a potential threat to commercial production of lavender. References: (1) J. F. Leslie and B. A. Summerell. Page 212 in: The Fusarium Laboratory Manual. Blackwell Publishing Professional, Hoboken, NJ, 2006. (2) P. C. Nelson et al. Clin. Microbiol. Rev. 7:479, 1994.

scholarly journals First Report of Fusarium Wilt in Blueberry (Vaccinium corymbosum) Caused by Fusarium oxysporum in China

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1158-1158 ◽  
Author(s):  
Y. H. Liu ◽  
T. Lin ◽  
C. S. Ye ◽  
C. Q. Zhang
Keyword(s):  
Fusarium Oxysporum ◽  
Infected Plant ◽  
Morphological Characteristics ◽  
Vaccinium Corymbosum ◽  
Morphological Characterization ◽  
Internal Transcribed Spacers ◽  
Fluorescent Light ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
First Report

Blueberry (Vaccinium corymbosum) production is developing quickly in China with about 20,000 ha presently cultivated. In 2010 in Lin'an, Zhejiang Province, plants developed an apparently new disease of blueberry (cv. Duke) with symptoms consisting of wilting of foliage, stunting of plants, and reduced fruit yields. Internal vascular and cortical tissues of plant crowns showed a brown to orange discoloration. Approximately 3% of the plants in the commercial plantings were affected and eventually died after 50 to 60 days. Infected plant samples (stems and roots) collected from different fields were surface sterilized with 1.5% sodium hypochlorite for 2 min, rinsed in water, plated on 2% potato dextrose agar (PDA), and incubated at 25°C in the dark for 1 week. Single conidium cultures were consistently isolated and cultured on acidified PDA (APDA) for morphological characterization (1,2). Colonies were light with purple mycelia, and beige or orange reverse colony colors developed after 7 days incubation at 25°C. Colonies producing abundant microconidia and macroconidia. Microconidia were hyaline and oval-ellipsoid to cylindrical (3.9 to 9.6 × 1.1 to 3.4 μm). Macroconidia were 3 to 5 septate and fusoid-subulate with a pedicellate base (28.6 to 37.5 × 3.3 to 4.2 μm). Morphology and development of macroconidia and microconida were consistent with a description of Fusarium oxysporum Schltdl (1,2). The ribosomal internal transcribed spacers ITS1 and ITS2 of eight isolates were amplified using primers ITS1/ITS4 on DNA extracted from mycelium and nucleotide sequences showed 100% similarity to that of F. oxysporum. To confirm pathogenicity, 20 blueberry plants (cv. Duke) were inoculated by dipping the roots into a conidial suspension (107 conidia per ml) for 30 min. The inoculated plants were transplanted into pots containing sterilized peat and maintained at 25°C and 100% relative humidity in a growth chamber with a daily 12-h photoperiod of fluorescent light. The pathogenicity test was conducted twice. Within 40 days, all inoculated plants developed wilt symptoms similar to that observed in the field. No symptoms were observed on plants dipped into distilled water. The fungus was successfully re-isolated from crowns and roots cultured on APDA, exhibiting morphological characteristics identical to F. oxysporum (1,2), confirming Koch's postulates. To our knowledge, this is the first report of blueberry wilt caused by Fusarium. References: (1) P. M. Kirk et al. The Dictionary of the Fungi, 10th edition, page 159. CABI Bioscience, Wallingford, UK, 2008. (2) W. C. Snyder and H. N. Hansen. Am. J. Bot. 27:64, 1940.

scholarly journals First Report of Fusarium Wilt Caused by Fusarium oxysporum on Strawberry in Spain

Plant Disease ◽  
2009 ◽  
Vol 93 (3) ◽  
pp. 323-323 ◽  
Author(s):  
F. T. Arroyo ◽  
Y. Llergo ◽  
A. Aguado ◽  
F. Romero
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Potato Dextrose Agar ◽  
Fluorescent Light ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Soilless Culture ◽  
Fragaria Ananassa ◽  
Pcr Assay ◽  
First Report

In the spring of 2007, wilted and dead strawberry plants (Fragaria × ananassa Duch. cvs. Camarosa and Ventana) were observed in a soilless culture system in Huelva, southwestern Spain. Approximately 8% of the plants in the field died. Isolations from necrotic crowns and roots and necrotic flowers were made on potato dextrose agar after disinfestation in 0.6% NaOCl for 30 s. Colonies with light purple mycelia and beige or orange reverse colony colors developed after 9 days of incubation at 25°C. Colonies produced abundant microconidia, macroconidia, and chlamydospores. Microconidia were hyaline and oval-ellipsoid to cylindrical (5.9 to 9.2 × 2.1 to 3.4 μm). Macroconidia were 3 to 5 septate and fusoid-subulate with a pedicellate base (28.8 to 37.3 × 3.2 to 4.3 μm). Morphology and growth matched descriptions of Fusarium oxysporum Schlechtend emend. Snyder & Hansen (2). A PCR assay for amplification of r-DNA using primers PFO2 and PFO3 established the identity of the isolate as F. oxysporum (1). To confirm the pathogenicity of the fungus, roots of 30-day-old strawberry cvs. Camarosa and Ventana (20 plants each) were inoculated by dipping the roots into a conidial suspension (107 conidia per ml) for 15 min. The inoculated plants were transplanted into plastic pots containing sterilized peat and maintained at 25°C and 100% relative humidity in a growth chamber with a daily 12-h photoperiod of fluorescent light. The pathogenicity test was conducted twice. Within 30 days, all inoculated plants developed wilt symptoms similar to that observed in the field and eventually 75% of the plants died. No symptoms were observed on plants dipped in distilled water. The fungus was successfully reisolated from crowns, roots, and necrotic flowers, fulfilling Koch's postulates. To our knowledge, this is the first report of the occurrence of Fusarium wilt caused by F. oxysporum on strawberry plants in Spain. References: (1) V. Edel et al. Mycol. Res. 104:518, 2000. (2) W. C. Snyder and H. N. Hansen. Am. J. Bot. 27:64, 1940.

scholarly journals First Report of Colletotrichum chrysophilum Causing Apple Bitter Rot in Spain

Plant Disease ◽  
2021 ◽  
Author(s):  
Jordi Cabrefiga ◽  
Daniel Pizà ◽  
Pere Vilardell ◽  
Jordi Luque
Keyword(s):  
Species Complex ◽  
Intergenic Spacer ◽  
Width Ratio ◽  
Conidial Suspension ◽  
Water Control ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Intergenic Spacer Region ◽  
Bitter Rot ◽  
Apple Bitter Rot

Bitter rot of apple (Malus × domestica Borkh.) is a cosmopolitan disease affecting fruit and causes considerable losses worldwide. In September 2020, symptoms of bitter rot were observed on ‘Pink Lady’ apples in two orchards (~2.5 ha each) in Gualta, Catalonia, Spain (42.03803 N, 3.09831 E, and 42.03942 N, 3.10931 E). Early symptoms consisted of light brown and sunken circular lesions (1-4 mm) that enlarged over time, later becoming dark brown and water soaked, and extending cone-shaped toward the core. Sporulation was mostly noticed in larger lesions. Estimated incidence was 2% and 20% of 150 trees surveyed in each orchard, respectively. Twenty-one fungal isolates were obtained from diseased fruit by culturing small pieces of necrotic tissue on potato dextrose agar (PDA) amended with rifampicin at 50 mg/liter. Colonies on PDA looked identical. They were cottony, initially light-gray colored on top and darkening with age; colony reverse initially cream colored and darkening with age. Conidia were produced in orange acervular masses on Spezieller Nährstoffarmer Agar, and were aseptate, hyaline, cylindrical with obtuse ends, and measuring 10.1 to 14.7 × 4.5 to 7.1 μm (average 13.1 ± 1.04 × 5.3 ± 0.67 μm [mean ± SD], n = 50), with a mean length/width ratio 2.6 ± 0.39 (n = 16 isolates). Perithecia were not observed. Based on the conidial morphology, the isolates were tentatively identified as belonging to the Colletotrichum gloeosporioides species complex (Weir et al. 2012). Total genomic DNA was extracted from all isolates and six nuclear regions were amplified and partially sequenced: the internal transcribed spacer region of rDNA (ITS), the mating type protein 1-2-1 gene and the Mat1-2-1-Apn2 intergenic spacer region (ApMAT), actin (ACT), calmodulin (CAL), glyceraldehyde 3-P dehydrogenase (GAPDH), and tubulin (TUB2). The sequences for each region were 100% identical across all isolates. BLAST searches in GenBank showed 99-100% identity with sequences of various C. chrysophilum W.A.S. Vieira, W.G. Lima, M.P.S. Câmara & V.P. Doyle strains including the ex-type CMM4268 (Vieira et al. 2017). Sequences of the representative isolate CJL1080 were deposited in GenBank (ACT, MZ488944; ApMAT, MZ442299; CAL, MZ488945; GAPDH, MZ488946; ITS, MZ443972; TUB2, MZ442300). A multilocus phylogenetic analysis through Bayesian inference conducted with the obtained sequences and reference ones (Khodadadi et al. 2020) revealed that our isolates clustered well within C. chrysophilum, as suggested by BLAST results. To confirm Koch’s postulates, isolates CJL1080 and CJL1095 were inoculated on ‘Pink Lady’ apples. Six surface-sterilized fruits per isolate were wound-inoculated four times each with either 20 μl of a conidial suspension (105 conidia/ml) or sterile distilled water (control). After 7 days of incubation in a moist chamber at 22°C, symptoms compatible with Colletotrichum infection were observed around the wounds, whereas control inoculations remained symptomless. The fungus was reisolated from all the lesions and identified through its morphological traits and DNA sequencing (ApMat, CAL, and GAPDH). No fungus was isolated from the controls. Taxa of the C. gloeosporioides species complex causing bitter rot have been recently reported in Europe (Grammen et al. 2019; Nodet et al. 2019). This is the first report of C. chrysophilum causing apple bitter rot in Spain, which expands the knowledge on the geographic distribution of this important pathogen of apple in Europe.

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