scholarly journals Genetic Diversity, Virulence, and Meloidogyne incognita Interactions of Fusarium oxysporum Isolates Causing Cotton Wilt in Georgia

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 948-956 ◽  
Author(s):  
Alois A. Bell ◽  
Robert C. Kemerait ◽  
Carlos S. Ortiz ◽  
Sandria Prom ◽  
Jose Quintana ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Fusarium Oxysporum ◽  
Meloidogyne Incognita ◽  
Root Knot Nematode ◽  
Soil Infestation ◽  
Causal Pathogen ◽  
Complementation Groups ◽  
Shoot Weight ◽  
Cotton Wilt ◽  
Significant Disease

Locally severe outbreaks of Fusarium wilt of cotton (Gossypium spp.) in South Georgia raised concerns about the genotypes of the causal pathogen, Fusarium oxysporum f. sp. vasinfectum. Vegetative complementation tests and DNA sequence analysis were used to determine genetic diversity among 492 F. oxysporum f. sp. vasinfectum isolates obtained from 107 wilted plants collected from seven fields in five counties. Eight vegetative complementation groups (VCG) were found, with VCG 01117B and VCG 01121 occurring in 66% of the infected plants. The newly recognized VCG 01121 was the major VCG in Berrien County, the center of the outbreaks. All eight VCG resulted in significant increases in the percentages of wilted leaves (27 to 53%) and significant reductions in leaf weight (40 to 67%) and shoot weight (33 to 60%) after being stem punctured into Gossypium hirsutum ‘Rowden’. They caused little or no significant reductions in shoot weight and height or increases in foliar symptoms and vascular browning in a soil-infestation assay. Soil infestation with Meloidogyne incognita race 3 (root-knot nematode) alone also failed to cause significant disease. When coinoculated with M. incognita race 3, all VCG caused moderate to severe wilt. Therefore, the VCG identified in this study belong to the vascular-competent pathotype, and should pose similar threats to cotton cultivars in the presence of the root-knot nematode. Use of nematode-resistant cultivars, therefore, is probably the best approach to control the disease in Georgia.

scholarly journals Detection and Characterization of Fusarium oxysporum f. sp. vasinfectum VCG0114 (Race 4) Isolates of Diverse Geographic Origins

Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 1998-2009 ◽  
Author(s):  
Alois A. Bell ◽  
Aixing Gu ◽  
Jim Olvey ◽  
Tanya A. Wagner ◽  
Javlon J. Tashpulatov ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Historical Collections ◽  
Specific Pcr ◽  
Reference Isolate ◽  
Compatibility Analysis ◽  
Geographic Origins ◽  
Soil Infestation ◽  
Pcr Method ◽  
Cotton Wilt ◽  
Race 4

A highly virulent cotton wilt pathogen, Fusarium oxysporum f. sp. vasinfectum VCG0114 (race 4) was found in West Texas in 2017, after being known in California since 2001. Isolates obtained from wilted plants collected in 2017 from Texas, in 2015 from China, and during 2001 to 2014 from California and isolates from historical collections including the race 4 reference isolate were characterized by soil-infestation pathogenicity assays, DNA sequence analysis, and vegetative compatibility analysis. All obtained F. oxysporum f. sp. vasinfectum isolates belonged to VCG0114. All of these isolates, except one isolate from China, caused disease in a soil-infestation assay without nematodes. Thus, they belong to the nematode-independent pathotype. Texas isolates were significantly more virulent than were isolates from China or California on Gossypium barbadense ‘Pima S-7’. Four different genotypes (N, T, MT, and MiT) were identified based on the transposable element Tfo1 insertion into the PHO gene and independent MULE or MITE insertions into the Tfo1 transposon. Some significant differences in virulence were detected among the genotypes in some locations. No differences in pathogenicity were observed between the California and China collection isolates on Pima S-7, and the virulence of the major genotypes was similar on the Gossypium hirsutum cultivar ‘Stoneville 474’ or the Barbren 713 germplasm line. Simple polymerase chain reaction (PCR) methods were developed to specifically determine and detect the four genotypes within VCG0114. A specific PCR method to detect all VCG0114 isolates was also developed. These methods will facilitate the timely identification of infested fields and seed lots and the elucidation of evolutionary relationships among the isolates. This should help to closely monitor the movement of the pathogen and reduce dissemination of these devastating pathogens.

scholarly journals Interaction of Meloidogyne incognita and fungi: a potential threat to cotton crop in Punjab

2021 ◽  
Vol 58 (04) ◽  
pp. 1277-1290
Author(s):  
Mehwish Naz
Keyword(s):  
Fusarium Oxysporum ◽  
Root System ◽  
Meloidogyne Incognita ◽  
Disease Incidence ◽  
Wilt Disease ◽  
Economic Losses ◽  
Root Knot Nematodes ◽  
Nematode Reproduction ◽  
Colletotrichum Spp ◽  
Cotton Wilt

Cotton is an important cash crop of Pakistan and is severely affected with wilt in cotton-growing areas of Punjab province. Research was carried out on two major pathogens of cotton Fusarium oxysporum f. sp. vasinfectum and Meloidogyne incognita and their possible role in wilt disease complex. During 2017-19, a survey of cotton growing areas of Punjab (Jhang, Multan, Vehari, Mianwali, Rahim Yar Khan, Bahawalpur, Kabir Wala, Dakota, Basti Dharik, Tibba Sultan Pur, Rajan Pur, Chak 27 (Layyah), Chak 99B (Layyah), Lodhran, Fateh Pur and Dagar Rohtass) was conducted to collect a sample on symptomology basis of yellowing of leaves, discoloured bark of lower part of the stem, blackened xylem vessel and wilting. Data were recorded on wilt disease incidence, prevalence, associated pathogens and root-knot nematodes. Prevalence of cotton wilt was recorded the maximum 85% in areas of Vehari, Kabir Wala and Rajan Pur while the maximum incidence in both Multan and Tibba Sultan Pur was 15%. Percentage association of wilting fungi was recorded from the soil, roots, stem and leaves on placing them in artificial media and soil dilution techniques were used to determine fungi in rhizosphere such as Fusarium oxysporum, Verticillium spp., Penicillium spp., Aspergillus spp., Rhizoctonia spp., Colletotrichum spp., Rhizopus spp., Mucor and Pythium. Root associated fungi were isolated by Hyphal tip method and isolated F. oxysporum, Rhizoctonia spp. and Pythium spp. From stem and leaf sample, F. oxysporum, Verticillium spp., Colletotrichum spp., Alternaria spp. and Botryodiplodia spp. were recorded. Relative density nematode was recorded from different locations and highest occurrence was observed in Bahawalpur (85%) by using different extraction methods. Eggs masses of root knot nematodes were staining by using Phloxin B and nematodes inside root system was done by using acid fuchsin. Nematode reproduction parameters like No. of J2/roots system, J2 in 100ml of soils, eggs masses/root system, females/ roots system, galls/ root system were recorded. Cotton wilt caused by the interaction of Fusarium and Root knot nematode is threat to cotton industry in Pakistan and it should be treated to avoid economic losses.

THE INTERACTION OF PLANT, PATHOGEN, AND SCAPTOCORIS TALPA CHAMP

1961 ◽  
Vol 39 (3) ◽  
pp. 695-703 ◽  
Author(s):  
M. I. Timonin
Keyword(s):  
Fusarium Oxysporum ◽  
Plant Pathogen ◽  
Meloidogyne Incognita ◽  
Microbial Population ◽  
Volatile Matter ◽  
Soil Samples ◽  
Root Knot Nematode ◽  
Selective Toxicity ◽  
Tomato Seedling ◽  
Tomato Seedlings

The effects of the odoriferous volatile matter produced by Scaptocoris talpa Champ on the activity of Fusarium oxysporum f. cubense (E.F.S.) Sny. and Hans., F. oxysporum f. lycopersici (Sacc.) Sny. and Hans., and Meloidogyne incognita in soil, and its phytotoxicity to tomato seedlings, were investigated.The results obtained indicated that 50–75 insects per pot protected tomato seedlings (Bonny Best) and banana plants (Gros Michel) from attack by their respective fungus pathogens and one insect per 2 grams of soil protected tomato seedlings from attack by root-knot nematode.The apparatus especially constructed to study the phytotoxicity of odoriferous volatile matter to tomato seedlings and its effect on microbial population of the soil was described. By means of this apparatus it was found that 6 days of a weak flow of a mixture of air and volatile matter produced by 350–400 insects was not phytotoxic to six tomato seedlings. Furthermore, it was also found that volatile matter produced by 800 insects, under the same conditions, was not toxic to one tomato seedling. Under similar conditions the non-phytotoxic concentration of volatile matter produced by 350–400 insects reduced the density of F. oxysporum f. cubense population in soil samples containing 25 and 15% (w/w) of moisture by 61.20 and 45.78% respectively.It was also demonstrated that one insect per 2 grams of soil infested with the root-knot nematode during 16 hours' incubation produced a nematocidal concentration of volatile matter.The possibility of selective toxicity of volatile odoriferous matter to various bacteria is also discussed.

scholarly journals Retention of Resistance to Fusarium oxysporum f. sp. niveum in Cucurbit Rootstocks Infected by Meloidogyne incognita

Plant Disease ◽  
2018 ◽  
Vol 102 (9) ◽  
pp. 1820-1827 ◽  
Author(s):  
Anthony P. Keinath ◽  
Paula A. Agudelo
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Meloidogyne Incognita ◽  
Interspecific Hybrid ◽  
Bottle Gourd ◽  
Root Knot Nematode ◽  
Summer Squash ◽  
Race 1 ◽  
Race 2 ◽  
Southern Root Knot Nematode

Interspecific hybrid squash (Cucurbita maxima × C. moschata ‘Strong Tosa’) and bottle gourd (Lagenaria siceraria ‘Macis’) rootstocks are resistant to Fusarium oxysporum f. sp. niveum but susceptible to Meloidogyne incognita (Southern root-knot nematode). Coinfection of Early Prolific Straightneck summer squash (C. pepo) with root-knot nematode and F. oxysporum f. sp. niveum has been reported to increase susceptibility to Fusarium wilt. The objectives of this study were to determine whether such an interaction occurred between M. incognita and F. oxysporum f. sp. niveum races 1 and 2 on Strong Tosa, Macis, and watermelon cultivars Fascination (resistant to race 1) and Tri-X 313 (susceptible to both races). Hosts were inoculated in a greenhouse with one of four pathogen treatments: F. oxysporum f. sp. niveum, M. incognita, both pathogens, or neither pathogen. Galling was present on ≥10% of the root systems of 90% of the plants inoculated with M. incognita. Bottle gourd had less galling than interspecific hybrid squash. Plants not inoculated with F. oxysporum f. sp. niveum did not wilt. Four weeks after inoculation, incidence and severity of Fusarium wilt and recovery of F. oxysporum did not differ for any hosts inoculated with F. oxysporum f. sp. niveum alone and F. oxysporum f. sp. niveum plus M. incognita (host–treatment interactions not significant). In general, Early Prolific Straightneck grouped with the F. oxysporum f. sp. niveum-resistant rootstocks when inoculated with F. oxysporum f. sp. niveum race 2 and with the susceptible watermelon when inoculated with race 1, regardless of inoculation with M. incognita. Recovery of F. oxysporum from stems of inoculated watermelon was greater than recovery from the other three hosts, regardless of nematode inoculation. In conclusion, our experiments do not support the hypothesis that resistance to F. oxysporum f. sp. niveum in cucurbit rootstocks or resistant watermelon cultivars would be compromised when M. incognita infects the roots.

Influence of the mutualistic endophyte Fusarium oxysporum 162 on Meloidogyne incognita attraction and invasion

Nematology ◽  
2007 ◽  
Vol 9 (6) ◽  
pp. 771-776 ◽  
Author(s):  
Richard Sikora ◽  
Abd El-Fattah Dababat
Keyword(s):  
Fusarium Oxysporum ◽  
Root Exudates ◽  
Meloidogyne Incognita ◽  
Repellent Activity ◽  
Choice Test ◽  
Root Knot Nematode ◽  
Tomato Root ◽  
Tomato Roots

AbstractThe non-pathogenic endophytic Fusarium oxysporum strain 162 (FO162) has been selected for its capacity to reduce root-knot nematode galling on tomato. The objectives of this study were to investigate the influence of this fungus on invasion of tomato roots by Meloidogyne incognita. The number of M. incognita that invaded roots of plants treated with FO162 was significantly lower (reductions of 36.0-55.9%) than in the non-treated controls in linked twin-pot chambers. The results demonstrated that colonisation of the roots by FO162 affects the number of M. incognita that penetrate the roots. The results of a choice test in the absence of a plant indicated that the tomato root exudates collected from plants colonised by FO162 are either less attractive or they exude substances that have repellent activity toward M. incognita juveniles.

scholarly journals Cucurbit Rootstocks Resistant to Fusarium oxysporum f. sp. niveum Remain Resistant When Coinfected by Meloidogyne incognita in the Field

Plant Disease ◽  
2019 ◽  
Vol 103 (6) ◽  
pp. 1383-1390 ◽  
Author(s):  
Anthony P. Keinath ◽  
W. Patrick Wechter ◽  
William B. Rutter ◽  
Paula A. Agudelo
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Meloidogyne Incognita ◽  
Interspecific Hybrid ◽  
Citrullus Lanatus ◽  
Root Knot Nematode ◽  
Progress Curve ◽  
Triploid Watermelon ◽  
Race 2 ◽  
Southern Root Knot Nematode

Interspecific hybrid squash (Cucurbita maxima × Cucurbita moschata) rootstocks used to graft watermelon (Citrullus lanatus var. lanatus) are resistant to Fusarium oxysporum f. sp. niveum, the fungus that causes Fusarium wilt of watermelon, but they are susceptible to Meloidogyne incognita, the southern root knot nematode. A new citron (Citrullus amarus) rootstock cultivar Carolina Strongback is resistant to F. oxysporum f. sp. niveum and M. incognita. The objective of this study was to determine if an interaction between M. incognita and F. oxysporum f. sp. niveum race 2 occurred on grafted or nongrafted triploid watermelon susceptible to F. oxysporum f. sp. niveum race 2. In 2016 and 2018, plants of nongrafted cultivar Fascination and Fascination grafted onto Carolina Strongback and interspecific hybrid squash cultivar Carnivor were inoculated or not inoculated with M. incognita before transplanting into field plots infested or not infested with F. oxysporum f. sp. niveum race 2. Incidence of Fusarium wilt and area under the disease progress curve did not differ when hosts were inoculated with F. oxysporum f. sp. niveum alone or F. oxysporum f. sp. niveum and M. incognita together. Fusarium wilt was greater on nongrafted watermelon (78% mean incidence) than on both grafted rootstocks and lower on Carnivor (1% incidence) than on Carolina Strongback (12% incidence; P ≤ 0.01). Plants not inoculated with F. oxysporum f. sp. niveum did not wilt. At the end of the season, Carnivor had a greater percentage of the root system galled than the other two hosts, whereas galling did not differ on Fascination and Carolina Strongback. F. oxysporum f. sp. niveum reduced marketable weight of nongrafted Fascination with and without coinoculation with M. incognita. M. incognita reduced marketable weight of Fascination grafted onto Carnivor compared with noninoculated, nongrafted Fascination. In conclusion, cucurbit rootstocks that are susceptible and resistant to M. incognita retain resistance to F. oxysporum f. sp. niveum when they are coinfected with M. incognita.

scholarly journals Histopathology of Interrelations between Fusarium oxysporum f. sp. dioscoreae and two nematode species on yam

1969 ◽  
Vol 70 (4) ◽  
pp. 245-254
Author(s):  
Ana E. Montalvo ◽  
Pedro L. Meléndez
Keyword(s):  
Fusarium Oxysporum ◽  
Meloidogyne Incognita ◽  
Vascular System ◽  
Nematode Species ◽  
Root Knot Nematode ◽  
Dioscorea Rotundata ◽  
Pratylenchus Coffeae ◽  
Lesion Nematode ◽  
Root Tissues ◽  
Histopathological Effects

Experiments were conducted in the greenhouse to elucidate the histopathological effects of a possible interrelationship between the nematodes Meloidogyne incognita and Pratylenchus coffeae and the fungus Fusarium oxysporum f. sp. dioscoreae on yam (Dioscorea rotundata cv Habanero). Separate and combined inoculations were made with the fungus and the nematodes. Longitudinal and transverse sections of root tissues collected at 14, 42 and 72 days after inoculation showed that colonization by the fungus occurred indiscriminately, either inter- or intracellularly. Colonization in the stem was restricted to the vascular system, where abundant proliferation of hyphae was observed, mainly in the nodal tissues. Apparently, the root-knot nematode (M. incognita), as well as the fungus, colonized different sectors of the tissues invaded. However, abundant and vigorous hyphae were present in sections of tissues modified by M. incognita. It may be concluded from these studies that a positive Meloidogyne-Fusarium interaction occurs in yam. The lesion nematode (P. coffeae) was sometimes observed together with the fungus within the same tissues. However, this association did not appear to considerably accelerate the severity and/or the incidence of wilt caused by Fusarium.

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