scholarly journals Characterization of Pathogenic and Nonpathogenic Fusarium oxysporum Isolates Associated with Commercial Tomato Crops in the Andean Region of Colombia

Pathogens ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 70 ◽  
Author(s):  
Sandra L. Carmona ◽  
Diana Burbano-David ◽  
Magda R. Gómez ◽  
Walter Lopez ◽  
Nelson Ceballos ◽  
...  

In Colombia, tomato production under protected conditions represents an important economic contribution to the agricultural sector. Fusarium wilt diseases, caused by pathogenic formae speciales of the soil-borne fungus Fusarium oxysporum Schltdl., cause significant yield losses in tomatoes throughout the world. Investigation of the F. oxysporum–tomato pathosystem in Colombia is required to develop appropriate alternative disease management. In this study, 120 fungal isolates were obtained from four different departments in the Central Andean Region in Colombia from tomato crops with symptoms of wilt disease. A molecular characterization of the fungal isolates was performed using the SIX1, SIX3, and SIX4 effector genes of Fusarium oxysporum f. sp. lycopersici W.C. Snyder & H.N. Hansen (Fol). Additionally, we developed a new specific marker to distinguish between Fusarium oxysporum f. sp. radicis-lycopersici Jarvis & Shoemaker (Forl) and Fol isolates. Furthermore, a phylogenetic analysis using the Translation Elongation Factor 1-alpha (EF1a) gene was performed with the collected isolates. Two isolates (named Fol59 and Fol-UDC10) were identified as Fol race 2, four isolates were identified as Forl, six isolates were identified as F. solani, and most of the isolates were grouped within the F. oxysporum species complex. The phylogenetic tree of EF1a showed that most of the isolates could potentially correspond to nonpathogenic strains of F. oxysporum. Additional pathogenicity assays carried out with Fol59 and Fol-UDC10 confirmed that both isolates were highly virulent strains. This study represents a contribution to the understanding of the local interaction between tomatoes and F. oxysporum in Colombia.

2007 ◽  
Vol 97 (4) ◽  
pp. 461-469 ◽  
Author(s):  
X. G. Zhou ◽  
K. L. Everts

Eighty-eight isolates of Fusarium oxysporum f. sp. niveum, collected from wilted watermelon plants and infested soil in Maryland and Dela-ware, were characterized by cross pathogenicity to muskmelon, race, and vegetative compatibility. Four isolates (4.5%) were moderately pathogenic to ≥2 of 18 muskmelon cultivars in a greenhouse test, and one representative isolate also was slightly pathogenic in field microplots. The four isolates all were designated as race 2, and were in vegetative compatibility group (VCG) 0082. Of the 74 isolates to which a VCG could be assigned, 41 were in VCG 0080, the VCG distributed most widely; 27 were in VCG 0082, and were distributed in half of the 20 watermelon fields surveyed; and 6 were in the newly described VCG 0083, and were restricted to three fields. Among the isolates in VCG 0080, 8 were designated as race 0, 21 as race 1, and 12 as race 2. Of the isolates in VCG 0082, 6 were designated as race 0, 11 as race 1, and 10 as race 2. All isolates in VCG 0083 were designated as race 2. Isolates from more than one race within the same VCG or isolates from more than one VCG were recovered from single plants and fields. No differences in aggressiveness on differential watermelon cultivars were observed among isolates from different VCGs of the same race. A diverse association between virulence and VCG throughout the Mid-Atlantic region suggests that the pathotypes of F. oxysporum f. sp. niveum may be of local origin or at least long existent in the region.


Plant Disease ◽  
2021 ◽  
Author(s):  
Maria Luz Herrero ◽  
Nina Elisabeth Nagy ◽  
Halvor Solheim

Lettuce (Lactuca sativa L.) is produced in Norway both in field and greenhouses. In Norway, greenhouse lettuce is one of the most important vegetables grown year-round. In winter 2018, wilting symptoms were observed on soil-grown lettuce of the cultivar Frillice in a greenhouse in south east Norway (Buskerud county). Affected plants showed stunted growth, wilting of outer leaves, and brownish discoloration of vascular tissues of taproots and crowns. According to the producer, the disease led to an estimated 10% of yield losses. Fungal isolates were obtained from crowns and roots of diseased plants collected from the greenhouse in 2018 and 2019. Two single spore isolates, 231274 from 2018 and 231725 from 2019, were used in further studies. The isolates were incubated on synthetic nutrient-poor agar (SNA) at 18-20 ⁰C, and a 12 hours dark, 12 hours UV light cycle. Isolate 231274 produced abundant macro- and microconidia characteristics of Fusarium oxysporum while macroconidia were never observed in isolate 231725. On potato dextrose agar (PDA), colonies of isolate 231274 were purple in color and colonies of isolate 231725 were pinkish with abundant aerial mycelium. For PCR-assay, DNA from mycelia was extracted using Easy-DNA kit (Invitrogen). A portion of the translation elongation factor 1-α (EF1-α) gene was amplified using primers F-728F (Carbone and Kohn. 1999) and EF2 (O'Donnell et al. 1998) as described by Aas et al. 2018. Blast analysis of both sequences (accession no. MW316853 for 231274 and MW316854 for 231275) obtained a 99% homology with the sequence of Fusarium oxysporum f.sp. lactucae (FOL) race 1 strain S1 (accession no. DQ837657)(Mbofung et al. 2007). Both isolates were identified as race 1 by using specific primers Hani3’ and Hanilatt3rev (Pasquali et al. 2007) as described by Cabral et al. 2014. To complete Koch’s postulate, lettuce plants of the cultivar Frillice were used. Race identity was confirmed using the differential lettuce cultivars Costa Rica No.4 (resistant to FOL race 1), Banchu Red Fire (resistant to FOL races 2 and 4) and Romana Romabella (resistant to FOL races 1 and 2) (Gilardi et al. 2017) provided by the breeding company Rijk Zwaan (De Lier, The Netherlands). For inoculation, roots of six 2-weeks old seedlings per cultivar were dipped in a spore suspension (1 x 106 CFU/ml) for 1 min, while controls were dipped in distilled water. Seedlings were planted in 250 ml pots containing fertilized potting substrate, and were placed in a greenhouse with temperature ranging from 15 to 35 ⁰C and an average of 23 ⁰C. After 10 days reduced growth was observed in cultivars Frillice and Banchu Red Fire for both fungal isolates. After 25 days wilting was observed in both cultivars. Affected plants presented discoloration of vascular tissue. No difference in growth was observed between cultivars Romana Romabella and Costa Rica No. 4 and their respective controls. FOL was re-isolated from all inoculated cultivars but not from controls. The colony patterns of the recovered isolates were the same than those of the isolates used for inoculation. These results confirm that the isolate belongs to race 1. Greenhouse lettuce in Norway is mainly produced in hydroponics. FOL is here reported to cause damages in soil- grown lettuce. Nevertheless FOL in hydroponic systems has been reported in Japan (Fujinaga et al. 2003) and Thailand (Thongkamngam and Jaenaksorn 2017). Thus, the possibility of infections in hydroponics remain a big concern for lettuce production in Norway.


2007 ◽  
Vol 73 (1) ◽  
pp. 29-34
Author(s):  
Norihito Yamauchi ◽  
Mamoru Satou ◽  
Jyuichi Shimazu ◽  
Takashi Shirakawa ◽  
Seizo Horiuchi

Plant Disease ◽  
2005 ◽  
Vol 89 (4) ◽  
pp. 366-372 ◽  
Author(s):  
Y. Kim ◽  
R. B. Hutmacher ◽  
R. M. Davis

Thirty isolates of Fusarium oxysporum f. sp. vasinfectum from California, Australia, China, and the American Type Culture Collection were characterized by partial sequences of translational elongation factor (EF-1α), phosphate permase (PHO), and beta-tubulin (BT) genes, restriction digests of the intergenic spacer (IGS) region of nuclear rDNA, and pathogenicity tests. Based on phylogenetic analysis of combined sequences of EF-1α, PHO, and BT genes, California isolates represented four lineages. Lineage I contained race 3, lineage II contained races 1, 2, and 6, lineage III contained race 8, and lineage IV contained race 4. The Australian isolates formed a strongly supported independent clade. There were nine haplotypes based on restriction digests of the IGS region. In greenhouse pathogenicity tests with California isolates, those from the race 4 lineage were highly aggressive on certain Pima cotton (Gossypium barbadense) cultivars and less aggressive on Upland cotton (Gossypium hirsutum) cultivars. All isolates belonging to the other lineages caused relatively mild symptoms on both Pima and Upland cultivars. This is the first report of the occurrence of races 3, 4, and 8 in California.


Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1118-1118 ◽  
Author(s):  
J.-H. Kwon ◽  
O. Choi ◽  
J. Kim

The hardy garden mum Chrysanthemum, or “mum” (Chrysanthemum × morifolium Ram.), is a popular flowering herbaceous perennial that is commonly grown for fall sales. In October 2011, suspected wilt disease was observed in potted hardy garden mums (cv. Guiin) grown in greenhouses in Jinju, South Korea. Symptoms included unilateral chlorosis of leaves at the stem apex. Wilted leaves occurred initially on the most severely affected side of the plant, but as the disease progressed, the entire plant wilted and died. Black necrosis and vascular discoloration at the base of stems always developed. Five fungal isolates, successfully isolated from 10 infected stems on potato dextrose agar (PDA), yielded rapidly growing floccose to felt-like colonies, initially white, but turning peach colored. The microconidia were ellipsoid, ovoid, and cylindrical, and measured 3 to 12 × 1 to 3 μm. The macroconidia were falcate, lunate, and measured 8 to 30 × 2 to 4 μm, and had 1 to 5 septa. Pathogenicity was studied in inoculated, potted plants in a greenhouse. A representative isolate of the fungus was grown on PDA at 20°C for about 10 days before inoculation. To obtain conidial suspensions, 10 ml of sterile distilled water (SDW) was added to the culture plates and scraped with a paintbrush to dislodge conidia. The suspension from the culture plates was filtered through cheesecloth and diluted to 2 × 104 micro- and macroconidia/ml with SDW. Nine 3-month-old hardy garden mums were planted in 20-cm-diameter plastic pots containing fine sand. After 10 days, the roots were cut to a depth of 5 cm on two sides of each plant at a distance of 2 cm from the stems. Then, 10 ml of conidial suspension were poured into each pot above the cuts roots, followed by 20 ml 12 days later. Three mums treated with SDW served as controls. Plants were fertilized twice weekly with 100 ml/pot of a nutrient solution (1) that lowered the soil pH and enhanced wilt development. Thirty days after inoculation, all of the artificially inoculated plants had wilted. The control mums remained healthy. The fungus was successfully reisolated to complete Koch's postulates. On the basis of the morphological characters, the fungus was identified as Fusarium oxysporum (3). To identify the isolated fungus, the complete internal transcribe spacer (ITS) rDNA and translation elongation factor 1-alpha (EF1-α) sequences were amplified using the primers ITS1/ITS4 and EF1/EF2, respectively, and sequenced. The resulting sequences were deposited in GenBank (Accession Nos. KC491873 and KC491875). A BLAST search of ITS rDNA (544 bp) and EF1-α (712 bp) sequences against a database of fungal isolates found 100% and 99% similarity to those of F. oxysporum, respectively. Fusarium wilt caused by F. oxysporim on C. morifolium has been previously recorded in North America and India but, to our knowledge, this is the first report of F. oxysporum causing wilt in hardy garden mum in Korea (2). F. oxysporum isolates causing wilts are specific to certain hosts and even to host varieties or cultivars. Further work is required to determine to which forma specialis and race the pathogen belongs. References: (1) A. W. Engelhard and S. S. Woltz. Proc. Fla. State Hort. Soc. 84:351, 1971. (2) H. C. Huang et al. Plant Pathol. Bull. 1:57, 1992. (3) C. V. Subramanian. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 217, 1970.


Plant Disease ◽  
1999 ◽  
Vol 83 (10) ◽  
pp. 967-967 ◽  
Author(s):  
V. M. Stravato ◽  
R. Buonaurio ◽  
C. Cappelli

During the summer of 1997, symptoms of Fusarium wilt were observed on tomato (Lycopersicon esculentum Mill.) cvs. Monica F1 and PS 110, which bear the I gene for resistance to race 1 of Fusarium oxysporum Schlechtend.:Fr. f. sp. lycopersici (Sacc.) W.C. Snyder & H.N. Hans., in two commercial production greenhouses in Latium (Fondi) and one greenhouse in Sardinia (Oristano). Infected plants showed yellowing, stunting, vascular discoloration, and premature death. A fungus from tomato stems with discolored vascular tissue was consistently isolated on potato dextrose agar (PDA) and, based on morphological features, was identified as F. oxysporum. To verify the pathogenicity of four fungal isolates, cv. Bonny Best tomato plants, which do not carry genes for Fusarium wilt resistance, were inoculated by dipping roots of 2-week-old seedlings in a suspension of 105 microconidia per ml for 30 s. Inocula were obtained from 1-week-old fungal cultures grown on PDA. Roots of control plants were dipped in water. Seedlings were transplanted to pots containing peat and river sand (1:1, vol/vol) and placed in a greenhouse at 20 to 25°C. One month after inoculation, all fungal isolates provoked wilting of inoculated plants. No symptoms were observed on control plants. The morphological features of the fungus reisolated from diseased plants were similar to those of the original isolates. Based on the pathogenicity test, we concluded that the fungal isolates belong to F. oxysporum f. sp. lycopersici. To determine the races of the fungal isolates, differential tomato lines VFN8 (I gene for resistance to race 1), Florida MH-1 (I and I2 genes for resistance to races 1 and 2), and I3R (I, I2, and I3 genes for resistance to races 1, 2, and 3) were inoculated with the four fungal isolates, using the same procedure described for the pathogenicity test. Because disease symptoms were detected on VFN8 but not on Florida MH-1 and I3R, we deduced that the fungal isolates belong to F. oxysporum race 2. This is the first report of F. oxysporum f. sp. lycopersici race 2 in Italy. Previous research indicated that race 1 is present in Italy (1). Currently, many commercially acceptable cultivars resistant to races 1 and 2 are available to Italian greenhouse growers. Reference: (1) M. Cirulli. Phytopathol. Mediterr. 4:63, 1965.


2002 ◽  
Vol 51 (5) ◽  
pp. 605-611 ◽  
Author(s):  
F. M. Alves-Santos ◽  
L. Cordeiro-Rodrigues ◽  
J. M. Sayagués ◽  
R. Martín-Domínguez ◽  
P. García-Benavides ◽  
...  
Keyword(s):  

2021 ◽  
Vol 7 (3) ◽  
pp. 194
Author(s):  
Carmen Gómez-Lama Cabanás ◽  
Antonio J. Fernández-González ◽  
Martina Cardoni ◽  
Antonio Valverde-Corredor ◽  
Javier López-Cepero ◽  
...  

This study aimed to disentangle the structure, composition, and co-occurrence relationships of the banana (cv. Dwarf Cavendish) root endophytome comparing two phenological plant stages: mother plants and suckers. Moreover, a collection of culturable root endophytes (>1000) was also generated from Canary Islands. In vitro antagonism assays against Fusarium oxysporum f.sp. cubense (Foc) races STR4 and TR4 enabled the identification and characterization of potential biocontrol agents (BCA). Eventually, three of them were selected and evaluated against Fusarium wilt of banana (FWB) together with the well-known BCA Pseudomonas simiae PICF7 under controlled conditions. Culturable and non-culturable (high-throughput sequencing) approaches provided concordant information and showed low microbial diversity within the banana root endosphere. Pseudomonas appeared as the dominant genus and seemed to play an important role in the banana root endophytic microbiome according to co-occurrence networks. Fungal communities were dominated by the genera Ophioceras, Cyphellophora, Plecosphaerella, and Fusarium. Overall, significant differences were found between mother plants and suckers, suggesting that the phenological stage determines the recruitment and organization of the endophytic microbiome. While selected native banana endophytes showed clear antagonism against Foc strains, their biocontrol performance against FWB did not improve the outcome observed for a non-indigenous reference BCA (strain PICF7).


Author(s):  
Piero Sciavilla ◽  
Francesco Strati ◽  
Monica Di Paola ◽  
Monica Modesto ◽  
Francesco Vitali ◽  
...  

Abstract Studies so far conducted on irritable bowel syndrome (IBS) have been focused mainly on the role of gut bacterial dysbiosis in modulating the intestinal permeability, inflammation, and motility, with consequences on the quality of life. Limited evidences showed a potential involvement of gut fungal communities. Here, the gut bacterial and fungal microbiota of a cohort of IBS patients have been characterized and compared with that of healthy subjects (HS). The IBS microbial community structure differed significantly compared to HS. In particular, we observed an enrichment of bacterial taxa involved in gut inflammation, such as Enterobacteriaceae, Streptococcus, Fusobacteria, Gemella, and Rothia, as well as depletion of health-promoting bacterial genera, such as Roseburia and Faecalibacterium. Gut microbial profiles in IBS patients differed also in accordance with constipation. Sequence analysis of the gut mycobiota showed enrichment of Saccharomycetes in IBS. Culturomics analysis of fungal isolates from feces showed enrichment of Candida spp. displaying from IBS a clonal expansion and a distinct genotypic profiles and different phenotypical features when compared to HS of Candida albicans isolates. Alongside the well-characterized gut bacterial dysbiosis in IBS, this study shed light on a yet poorly explored fungal component of the intestinal ecosystem, the gut mycobiota. Our results showed a differential fungal community in IBS compared to HS, suggesting potential for new insights on the involvement of the gut mycobiota in IBS. Key points • Comparison of gut microbiota and mycobiota between IBS and healthy subjects • Investigation of cultivable fungi in IBS and healthy subjects • Candida albicans isolates result more virulent in IBS subjects compared to healthy subjects


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